McANDREW'S FLOATING 
 SCHOOL 
 
 A STORY FOR MARINE ENGINEERS 
 
 BY 
 
 CAPTAIN C. A. MCALLISTER 
 
 Engineer-in-Chief United States Eevenue Cutter Service, 
 Washington, D. C. 
 
 Author of "The Professor on Shipboard" 
 
 and many other Engineering 
 
 stories- 
 
 38 ILLUSTRATIONS 
 
 NEW YORK AND LONDON 
 
 INTEKNATIONAL MAKINE ENGINEERING 
 1914 
 

 REPRINTED FROM 
 INTERNATIONAL MARINE ENGINEERING 
 
 COPYRIGHT 1914 
 BY ALDRICH PUBLISHING CO. 
 
Introduction 
 
 In presenting these lectures of "McAndrew" in 
 book form, the author does so in the hope that they 
 may be of benefit to some of that great class of hard 
 workers whose life "below the grating" is but little 
 understood by the public at large. These men are the 
 backbone of modern seafarers, as they bear the heat 
 and burden of the work of sea transportation. Inured 
 from early youth to the hardest physical toil known to 
 man, it is scarcely to be presumed that their early edu- 
 cation is such as to fit them for the higher positions in 
 engineering; for example, those held by the licensed 
 engineer officers under whom they serve. 
 
 Yet all who come in contact with them know that 
 there is not another class of workers in any branch of 
 industry containing so large a number of young men 
 ambitious to reach higher positions. Such ambition, 
 of course, requires considerable study of the elements 
 of engineering. It must be admitted that even the sim- 
 plest of text-books on engineering subjects are couched 
 in such language, or so hampered by mathematical 
 formulae, plain as they may be to those whose rudi- 
 mentary education permits them to grasp their mean- 
 ing, as to defeat their very purpose. 
 
It has therefore been the aim in this course of lec- 
 tures to present abstruse engineering facts in a simple 
 and, it is hoped, as interesting a manner as possible. 
 Should it succeed in helping some of that type for 
 whom it has been written, the writer will feel much 
 encouraged. Certainly these men, the oilers, coal- 
 passers, watertenders and firemen. of the world's mer- 
 chant marine are deserving of the efforts of all who 
 can be of any assistance to them. The transformation 
 from sail to steam on the great oceans of the world has 
 been so rapid that poets and writers generally are still 
 sounding the praises in song and story of the old-time 
 manner and have not awakened to the fact that the 
 sailor has been replaced by the man in the fireroom or 
 engine-room. Some of the romance of the sea has dis- 
 appeared with the sailorman, but heroism is as much, 
 and more, in evidence with his begrimed successor. 
 Where in the annals of seafarers was ever shown 
 greater heroism than that displayed by the engineer's 
 force of the ill-fated Titanic, who, almost to the man, 
 sank with their ship and at their posts of duty? All 
 the world knows that these hundreds of brawny ar- 
 tisans of the deep could have seized the boats and es- 
 caped with their lives ; but they were men, and it is for 
 the thousands of men like them that this book i? 
 written. 
 
 G. A. MCALLISTER. 
 
CONTENTS. 
 
 PAGE 
 CHAPTER T. 
 
 Introducing James Donald McAndrew . 9 
 
 CHAPTER II. 
 
 School Opens -. ... 14 
 
 CHAPTER III. 
 
 Force, Work and Power, 
 
 
 CHAPTER IV. 
 
 
 Heat, Combustion 
 
 and the Generation of Steam. . . . 
 
 21 
 
 
 CHAPTER V. 
 
 
 Engineering Materials 
 
 30 
 
 
 CHAPTER VI. 
 
 
 Boilers 
 
 
 39 
 
 
 CHAPTER VII. 
 
 
 Boiler Fittings. . . 
 
 
 49 
 
 
 CHAPTER VIII. 
 
 
 Forced Draft .... 
 
 
 57 
 
 
 CHAPTER IX. 
 
 
 Engines 
 
 
 62 
 
 
 CHAPTER X. 
 
 
 Valves and Valve 
 
 Gear 
 
 77 
 
 
 CHAPTER XI. 
 
 
 Engine Fittings. . 
 
 
 87 
 
CHAPTER XII. 
 
 Condensers, Air and Circulating Pumps .......... 100 
 
 CHAPTER XIII. 
 
 Feed Water Filters, Pumps and Injectors ......... 112 
 
 CHAPTER XIV. 
 
 Evaporators and Distillers. ... ................. 123 
 
 CHAPTER XV. 
 
 Electricity .............................. ^7 
 
 CHAPTER XVI. 
 
 Pipes and Valves ............................. 
 
 CHAPTER XVII. 
 
 Indicators and Horse Power ................... 149 
 
 CHAPTER XVIII. 
 
 Care and Management of Boilers ................ 162 
 
 CHAPTER XIX. 
 
 Care and Management of Engines and Auxiliaries. . 178 
 
 CHAPTER XX. 
 
 Examination Questions and Answers ......... 195 
 
McAndrew's Floating School 
 
 CHAPTER I 
 
 Introducing James Donald McAndrew 
 
 "I'm tired of shoveling coal and being bossed around," re- 
 marked Tom O'Rourke, one of a party of four husky young 
 fellows who, at the end of a voyage, were just banking the 
 fires in the stokehold on board the coasting steamer Tusca- 
 rora, then lying at her pier on the East River. This remark 
 brought about a general laugh from the other members of 
 the party. "Well," replied Jim Pierce, after the laugh had 
 subsided, "what are you going to do about it? That's just 
 what I've been thinking prttty strongly about ; here I've been 
 three years on this packet, working like a dog, and I don't 
 see any chance of my ever getting anything better to do ; of 
 course, after a while, I may get a chance to squirt oil on that 
 old mill of ours, but what I want to do is to get a 'ticket' and 
 boss the job myself." 
 
 "Well, why don't you," rejoined Henry Nelson, another 
 member of the party. "The Chief told me the other day that 
 he had worked himself up from the bunkers, and he's pretty 
 good at figures, too. If we only had the head on us that he 
 has, we needn't wait long before the steamboat inspectors 
 would pass us out the right kind of a paper." 
 
 Gus Schmidt, the fourth member of the party, had, during 
 all this conversation, stood by quietly, drawing great puffs 
 of smoke out of his five-cent meerschaum, and taking in 
 everything that was said. As became his German ancestry, 
 
10 MC ANDREW'S FLOATING SCHOOL 
 
 he was stolid of disposition and not given to saying much un- 
 less he had something to say. Finally, after he thought it was 
 his turn to get into the conversation, he said: "You fellows 
 make me tired with all your- pipe- dreams ; why don't you get 
 down to business; now I'll tell you what let's do. I just 
 heard the 'Super' on the dock say, to-day that the bunch of 
 kettles in this ship are to come out, that we are going around 
 to Philadelphia to get some new ones, and the ship is to be 
 given a general overhauling at the same time/ so- as to put 
 her in good shape for the next season's work. The Chief is 
 going to boss the repairs, and the four of us are going to be 
 kept by to chip and paint the coal bunkers and do some other 
 high-class stunts like that. The whole job will last about six 
 months, and as we won't have anything particular to do at 
 night, let's buy some books and get the 'old man' to play 
 school teacher for us." 
 
 "Fine business, Dutchy," said O'Rourke ; "you've got a head 
 on you like a clock. We'll go to it." The idea also met the 
 approval of the other two, and it was decided to brace the 
 genial Chief with the proposition. 
 
 James Donald McAndrew was a young man, not of French 
 descent, as you no doubt may have surmised by this time, who 
 was born on the great East Side in New York some thirty- 
 eight years ago. Educated in the public schools until he was 
 fourteen, he had successfully served an apprenticeship in a 
 big general repair shop on the waterfront, and at the same 
 time had gone to night school at Cooper Union, where, being 
 naturally bright, he had become thoroughly grounded in the 
 rudiments of an engineering education. Being fond of the 
 water, he had shipped on board a twenty-five hundred ton 
 steamer as a fireman, and in a very short time had taken out 
 his license as a Third Assistant. Being naturally a hustler 
 and capable of making friends among his superior officers, 
 he found himself at the age of thirty-eight the Chief Engi- 
 
JAMES DONALD MC ANDREW H 
 
 neer on the Tuscarora, the biggest ship of the line. It was 
 therefore quite in keeping that the Superintendent should 
 have selected him as inspector of the extensive repairs the 
 ship was about to undergo. Unlike many young men of his 
 age who lead a seafaring existence, he took life somewhat 
 seriously and had gone through the trying years of his devel-^ 
 opment without falling into any bad habits. His father had 
 died when the young man had just started in as a Third 
 Assistant, which left upon him the responsibility of looking 
 after his widowed mother and two young sisters. Conse- 
 quently he was not given to wasting his money and could be 
 found generally attending strictly to his business instead of 
 roaming around town at nights when the ship was in port. 
 His kindly disposition, ready wit and general all-around abil- 
 ity had won for him the respect of the crew, so he was not 
 at all surprised this particular evening upon opening his state- 
 -room door in response to a knock to find four members of 
 the fireroom gang, hats in their hands, Banding on the out- 
 side. "Well, boys, what can I do for you?" was his cheerful 
 salutation. 
 
 O'Rourke, the self-constituted spokesman of the party, 
 blurted out: "You see, Chief, it's this way; us four young- 
 sters have an idea that we would like to get ahead in the 
 world, and there don't seem to be much of a show for us if 
 we don't get something in our heads. Dutchy Schmidt here 
 thinks that if we will get some books, you might help us out 
 when we get around to Philadelphia this winter putting in 
 the new boilers. We'll have every night in, and as we will all 
 live on the ship, we thought as how you might teach us 
 something for an hour or so every night. We'll make it all 
 right with you for the time you give us. What we want rs 
 to be able to get out our 'tickets' from the steamboat inspec- 
 tors, and we know that you can give us the right steer." 
 
 "So you want to make me a school teacher, eh?" laughingly 
 
12 MC ANDREW'S FLOATING SCHOOL 
 
 rejoined Me Andrew. "That isn't a bad idea, though, and if 
 you fellows mean business and will get right down to brass 
 tacks I might consider it. I want to tell you one thing right 
 now, and that is if I do undertake such a job I don't want any 
 monkey business. You'll have to study hard or you'll find 
 me worse than any old Yankee schoolmaster you ever dreamed 
 of. Before I sign up on this proposition I want to know 
 something about each of you. Of course I know you are all 
 pretty good firemen and 'tend to business, but what I must 
 find out from each of you is something about how much of an 
 education you have. I know you are not graduates of a high 
 school or you wouldn't be here flirting with a slice-bar and 
 wrestling with clinkers for a living. O'Rourke, let's hear your 
 spiel first." 
 
 "Well, sir," replied that worthy, "I ain't much on book 
 learning, but I can write pretty well, understand arithmetic, 
 have studied geography and know a little something about his- 
 tory. When I was a boy I used to know the Catechism from 
 one end to the other, but I'm a little shy on that now." 
 
 "Never mind," said McAndrew, "this will be no Sunday 
 school you are going to tackle. How about you, Nelson ?" 
 
 That descendant of some Norse king gave an outline of 
 his educational career which closely corresponded with 
 O'Rourke's, excepting the Sunday school part. Schmidt and 
 Pierce followed in about the same strain, so that the upshot 
 of it all was that Mr. McAndrew considered his contemplated 
 class was about on a par so far as their proposition was con- 
 cerned. 
 
 "I can see right now that I am up against a hard proposition 
 to train you fellows up so as to enable you to take out your 
 papers, but as long as you mean business I am willing to try 
 out your scheme," said the Chief. 
 
 "Thank you, sir," was the chorused reply from all four, as 
 light-heartedly they took their departure. Had they been col- 
 
JAMES DONALD MC ANDREW 13 
 
 lege boys one of them would probably have yelled out, 
 "What's the matter with McAndrew?" to be self-answered in 
 a raucous yell, "He's aH right," etc., but they had not yet 
 reached that high degree: if culture. 
 
CHAPTER II 
 
 School Opens 
 
 About two weeks later the Tuscarora steamed up the Dela- 
 ware River to the shipyard where the repairs were to be made, 
 fires were hauled, most of the crew discharged and prepara- 
 tions made to begin the work. The four young firemen and 
 Mr. McAndrew were kept very busy for a time after the 
 arrival of the ship, but it was finally decided that the school 
 should begin on what happened to be the first Monday night of 
 the month. The youngsters in the meantime had rigged up 
 a pretty fair school room in the engineer's storeroom, and 
 had hung up a good-sized blackboard on one of the bulkheads. 
 No testimony was given as to just where they obtained this 
 blackboard, but it is safe to say that the shipyard people must 
 have contributed involuntarily from their pattern and paint 
 shops toward the cause of education. 
 
 Monday night, shortly after supper, the first session of the 
 McAndrew School commenced without any frills or formali- 
 ties. There was no necessity for a roll-call, as a full attend- 
 ance was in evidence. O'Rourke, Pierce, Nelson and Schmidt 
 had each indulged in a clean shave for the momentous occa- 
 sion, and McAndrew himself appeared a little more perked 
 up than usual in honor of his debut as a teacher. 
 
 Assuming a demeanor somewhat in keeping with his new 
 responsibilities, McAndrew addressed his class as follows: 
 "Young men, we are about to start in oui course of training. 
 
SCHOOL OPENS 15 
 
 I don't propose to turn out a lot of high-brows from this 
 floating school, but what I do intend, if possible, is to drive 
 enough theory, or whatever you call it, into you to enable you 
 with practical experience to pass your examinations for a 
 license as assistant engineer before any board you happen to 
 go against. I have been making inquiries to find out just 
 what branches you ought to be drilled on to pass the exami- 
 nation, and I find that the law actually requires only two sub- 
 jects, and that is how to make calculations concerning a lever 
 safety-valve and how to figure out the staying of the flat 
 surfaces of a boiler. Of course, no man can be an engineer 
 who understands only those problems, and you will find that 
 before you ever get your 'ticket' you will have to get a good 
 general idea of the whole subject, as these local boards are 
 very thorough. These examinations won't be like the old 
 stories they tell about the examinations held in the early days 
 of the civil service, for example, of how a candidate for a 
 job in the Custom House was asked, 'How many Hessians 
 came over here during the Revolutionary War?' Not know- 
 ing definitely, he answered, 'A d n sight more than went 
 
 back,' and, as the story goes, he got the job. Another one was 
 the candidate for the position of letter carrier, who, when 
 asked, 'How many miles from the earth to thetmoon ?' replied, 
 'If I have to deliver letters there I don't want the job.' " 
 
 "You will find that the questions which the steamboat in- 
 spectors ask you to answer will be only such as you must 
 know to make successful marine engineers." 
 
 "I therefore propose to post you in a general way on the 
 principal things a seagoing engineer ought to know. I take 
 it for granted that all of you know enough about arithmetic 
 to make ordinary calculations, so we will not waste any time 
 in going over that subject, as you will get enough practice in 
 it as we go along on the other subjects." 
 
 "At the start, I will insist on each of you getting a thorough 
 
MC ANDREWS FLOATING SCHOOL 
 
 understanding of a few of the elementary definitions in what 
 is known as mechanics, as no one connected in any way with 
 engineering in any of its branches can make a success of it 
 unless he does understand these underlying facts." 
 
CHAPTER III 
 Force, Work and Power 
 
 "Come on, boys, let's turn to and get right at this business," 
 said McAndrew to his class, as they assembled on the follow- 
 ing night. "The first part of this course is going to be what 
 you all need the most a little instruction in elementary princi- 
 ples. - There is no good of a man trying to put a roof on his 
 house until he has at least a pretty fair foundation under it. 
 As I have already told you, I don't want to go into any 'high- 
 brow' theories with you, as both of us would be losing some- 
 thing valuable I'd lose my time and you would lose your 
 interest. 
 
 "In all branches of engineering the principal output is 
 power in one form or another. Now, it is a safe bet that none 
 of you knows exactly what power is. I want to get the right 
 idea of it firmly impressed on your memory, so that you will 
 not be like a certain Irishman I know of who, through politi- 
 cal influence, got a job to run a small steam engine in the 
 Capitol. A sightseer stopped to look at his engine one day, 
 and asked the son of Erin what horsepower it was. 'Horse- 
 power!' he ejaculated, 'horsepower be ; don't you see that 
 
 it runs be stame/ 
 
 "Now to understand what constitutes power you must con- 
 sider three elements force, distance and time. For instance, 
 here is a block of iron which weighs 5 pounds. I lift it -up 
 I foot from the deck by using force to overcome its weight, 
 
i8 MC ANDREW'S FLOATING SCHOOL 
 
 and in so doing I have performed work, which is measured 
 in what is known as foot-pounds; that is, I have performed 
 5 foot-pounds of work by overcoming the weight of this 
 5-pound block through a distance of i foot. Now get that 
 fixed in your mind, force is overcoming weight, and work 
 is overcoming weight through distance or space. Now it 
 wouldn't make any difference whether I lifted that 5-pound 
 weight a foot high in a second or ten minutes so far as the 
 term 'work' is concerned, but when you come to 'power' then 
 there is another thing to be considered, and that is the time it 
 takes to perform the work. In measuring anything you must 
 have a standard upon which to base your measurements; 
 thus you buy waste by the pound, oil by the gallon, etc., so 
 the early engineers in looking for a standard on which to 
 measure power quite naturally selected the horse, that faith- 
 ful beast which carries or pulls all manner of burdens for 
 mankind. As a result of experiments on a large number of 
 horses in England many years ago, it was decided that at an 
 average a horse could perform 33,000 foot-pounds of work 
 in one minute; hence this was fixed as the now almost uni- 
 versally adopted standard 'horsepower' for all engines. Al- 
 ways keep in mind, therefore, that power consists of three 
 things force, distance and time. Later on I'll show you how 
 to calculate the horsepower of an engine. 
 
 "The next foundation stone I want you to lay is to get the 
 right idea of the so-called mechanical powers. Only the other 
 day I heard Nelson say when he was working that small jack- 
 screw, 'Gee ! but this is a powerful little beggar.' Don't forget 
 one thing right at the start ; there never has been any kind of 
 a machine invented where you can get more power out of it 
 than you put in it. In fact, it is always a little less on ac- 
 count of the loss by friction. If that jack-screw appeared to 
 lift a weight of several tons with comparative ease, you must 
 remember that it only lifted it a few inches, while your 
 
FORCE, WORK AND POWER IQ 
 
 hand traveled a good many feet in working the bar. The 
 fundamental principle of all the mechanical powers is that the 
 weight, multiplied by the distance it moves through, is always 
 equal to the force multiplied by the distance it moves through. 
 Suppose we take this foot-rule and put it over a knife-edge on 
 the 4-inch mark. On the short end we will put these two 
 i-inch nuts and on the long end we will put one such nut, and 
 you see that they balance exactly. Why? Simply because 
 2X4=1X8 = 8. That is the principle of the lever, and 
 later on you will find that it is the principle of the lever safety 
 valve about which you will have to know before you can ever 
 get your 'ticket' from the steamboat inspector. 
 
 "The next thing you want to understand is the inclined 
 plane. Suppose you want to put a barrel of oil on a truck. 
 You can't lift it off the deck, so you go and get a plank, and, 
 single-handed, you can roll it up and put it in the truck. How 
 could you do it? Simply because you couldn't lift it bodily a 
 distance of perhaps 3 feet you rolled it up a plank 10 feet long. 
 In that manner, while the barrel was lifted vertically 3 feet, 
 you were shoving it for a distance of 10 feet. 
 
 "A wedge is simply a double inclined plane; to open up a 
 space Y 2 inch wide in a plank you often have to drive the 
 wedge lengthwise eight or ten times that distance. 
 
 "The screw, such as' that jack I was speaking of, is a com- 
 bination of the lever and the inclined plane. When you take 
 hold of the end of the bar and pull, it acts as a lever on the 
 head of the jack-screw. The thread is simply an inclined 
 plane wrapped around the bolt Between the two you can 
 exert a tremendous pressure to lift anything, but always 
 remember the great number of times you have to pull that bar 
 around, and compare the distance your hand travels with the 
 short distance the weight is lifted, then the 'tremendous pres- 
 sure' exerted won't seem to be so mysterious. 
 
 'There are several other so-called mechanical powers, but 
 
2O MC ANDREW S FLOATING SCHOOL 
 
 they are all practically based on the principles of the lever 
 and the inclined plane. 
 
 "No matter what tool or mechanical contrivance you are 
 using, just try to reason out on the principles I have given you 
 to-night how you are accomplishing the work. To-day, 
 O'Rourke, when you were lifting that main-bearing cap, you 
 know that you couldn't budge it alone, but you had no trouble 
 in hoisting it up with the chain tackle. How do you account 
 for that?" 
 
 O'Rourke scratched his head a bit and said, "Come to think 
 of it I guess I did pull that chain about a mile before I got 
 the cap up a foot ; the next time I'll let the Dutchman 'hist' 
 her up, while I take observations on how far he has to pull it." 
 
 "I see," said McAndrew, "that you'll make good as a scien- 
 tist, as the first thing any of them learn is to let some other 
 fellow do the manual labor." 
 
CHAPTER IV 
 
 Heat, Combustion and the Generation 
 of Steam 
 
 "Having told you something about mechanical powers, I 
 now propose to continue still further my remarks on ele- 
 mentary principles, and will take up the subjects of heat, 
 steam,, combustion, etc. In starting off I will ask you what 
 is steam?" As no one else seemed to volunteer an answer, 
 O'Rourke blurted out, "It's a white gas that kills you if you 
 breathe it." 
 
 "It will kill you all right, but please remember that steam 
 is not white until it is condensed into small particles of water 
 when it is formed in a boiler it is as colorless and invisible 
 as the air. I am afraid, however, that your idea of steam is 
 somewhat cloudy. Of course, you all know that when you 
 shovel coal in a furnace, and boil the water in the boiler, 
 steam is formed ; but how ? is the question. 
 
 "Heat, scientific men inform us, is a mode of motion. All 
 substances are composed of infinitesimal small particles called 
 molecules. Heat is the violent motion of these molecules, and 
 may be occasioned in two fundamental ways. The first is what 
 may be termed chemical action or combustion, and that is what 
 interests us most. The element known as carbon, of which 
 coal is largely composed, unites with another element known 
 as oxygen, and heat is generated. Thus we put coal contain- 
 ing carbon in a furnace and admit air containing oxygen 
 
22 MC ANDREWS FLOATING SCHOOL 
 
 through the grate bars, and heat results from the chemical 
 union of the two elements. They must unite in certain pro- 
 portions, so that is the reason you have to regulate the 
 dampers and ash-pit doors. The right proportion is one part 
 of carbon and two parts of oxygen. Always remember that 
 the air is just as essential in forming heat as is the coal." 
 
 "The air is much easier shoveling," broke in O'Rourke. Not 
 paying any attention to the interruption, McAndrew contin- 
 ued : "The right kind of a fireman is the one who pays 
 attention to his fires and allows the proper mixture of air to 
 reach the fires. If you put in too much coal, such as the 
 'crown-sheeters,' which O'Rourke likes to carry, the air does 
 not have sufficient chance to circulate through the hot coals 
 to make good combustion. If the clinkers and ashes are 
 allowed to collect on the grates, they also shut off the proper 
 amount of air and your fires get dead. Hence the best way to 
 make steam is to carry a fire of uniform thickness, not more 
 than 6 to 8 inches deep, and by means of the slice-bars keep 
 the ashes off the grates as much as possible. Another thing 
 is to keep your doors shut as much as you can ; too much air 
 is as bad as too little. When you have to throw in coal do it 
 quickly, and spread it evenly over the fires. If the conditions 
 are such that there is one part of the oxygen to one of carbon, 
 you will not make much steam, as such a mixture does not 
 burn simply smells bad. 
 
 "As I told you before, there is a method of measuring every- 
 thing by comparing it with some standard. This applies to 
 heat as much as it does to coal itself, only you do not meas- 
 ure 'heat by its weight, as it has none; therefore we must 
 measure it by its effect. One of the effects of applying heat to 
 metals is to cause them to expand or grow larger. Taking 
 advantage of this quality the thermometer was invented, which 
 records the expansion and contraction of mercury in a glass 
 tube as heat is applied. While the thermometer measures the 
 
HEAT, COMBUSTION AND THE GENERATION OF STEAM ,2J 
 
 degree of the heat in a relative manner it does not measure 
 the amount. Hence a unit amount of heat was decided to be 
 the amount necessary to raise i pound of water I degree on 
 the thermometer. They call that amount a British thermal 
 unit." 
 
 Schmidt was very much interested in this term and re- 
 marked, "I suppose O'Rourke would rather have it called an 
 Irish unit." 
 
 "Now it may interest you to know that a pound of good coal 
 ought to produce something more than 13,000 of these British 
 thermal units. Remember that, for by the time you boys get 
 to be chief engineers everybody will be buying coal by the 
 number of British thermal units it contains instead of specify- 
 ing some particular brand of coal, as is done now. If you are 
 not buying coal you will be buying fuel oil ; but even so you 
 will \vant to know the thermal units it contains. 
 
 "In order not to give you any wrong impressions as to the 
 amount of air necessary for combustion, I want to tell you 
 that for every pound of average coal there are needed about 
 two and two-thirds pounds of oxygen. As the air contains 
 only about one-quarter of its weight in oxygen, it is usual in 
 order to obtain a good draft to admit about 20 pounds of air 
 to the pound of coal. That means that approximately 250 
 cubic feet of air must be admitted to the furnaces for every 
 pound of coal that is burned. Fortunately, the air costs 
 nothing, or the process of making steam would be very ex~ 
 pensive. Although I have advised you to keep the furnace 
 doors open just as briefly as possible, do not forget that some 
 air must be admitted above the fire in order to attain proper 
 combustion. In all well-designed furnace fronts you will find 
 a number of holes for the admission of air, so you must see 
 that they are kept open. 
 
 "Now as to the other method of generating heat. All of 
 you have noticed that if you rub your hand briskly over a 
 
24 MC ANDREWS FLOATING SCHOOL 
 
 smooth piece of wood, for example, there is a sensation of 
 warmth. That is due to the energy you exert in the rubbing 
 process. If you do not keep a crank-pin well oiled you know 
 that it will soon become heated up, and if it is allowed to go 
 far enough it is quite possible that sparks would fly or the 
 metal become so heated as to show color. This is but 
 another example of energy being transformed into heat. You 
 all know that the heat from the steam is quite readily turned 
 into power or energy in the engine, so there must be some 
 standard system of comparing one with the other. I have 
 already told you that work is measured in foot-pounds, and 
 that heat is measured in British thermal units. A scientific 
 man named Joule therefore determined that 772 foot-pounds 
 of work was equivalent to a British thermal unit, and that is 
 the way that comparisons are made. O'Rourke, you are quite 
 a strong young man, but you can see that if you hustled as 
 fast as possible, you would not be able to turn out as much 
 work as even I pound of coal. That shows you the difference 
 between using your muscles and your brains. Coal is a very 
 cheap and able competitor of the man who only uses his 
 physical strength, but fortunately for mankind brains can- 
 not be bought so cheaply. 
 
 "We have seen how heat is generated from coal, and you 
 must keep in mind that heat is the source of all power for 
 marine propulsion. Water is found to be the ideal means of 
 conveyance for transforming the heat into power ; it is easily 
 converted into steam and it exists in great abundance. Hence 
 the large majority of marine engines are designed to work by 
 steam generated from water. You know that the result of 
 starting fires hi a boiler containing water is the generation of 
 steam. If you put a thermometer in the boiler water you 
 would see that some time after the fires are started the tem- 
 perature would gradually rise until it reached the boiling point, 
 usually taken at 212 degrees above zero. The heat thus ap 7 
 
HEAT, COMBUSTION AND THE GENERATION OF STEAM 2$ 
 
 plied is known as sensible heat, from the fact that it is ap- 
 parent to the senses. After having reached that temperature 
 it takes considerable time until steam is finally formed. This 
 is due to the fact that for water to be turned into steam a 
 great amount of heat is necessary to break up the liquid water 
 and transform it into the vapor steam. The heat thus ab- 
 sorbed by the water in the transformation is known as the 
 'latent' heat. To bring about this change there are required 
 966 British thermal units per pound of water, while it only 
 took 152 British thermal units per pound of water to raise it 
 from the temperature it was put into the boiler, say at 60 
 degrees, to the boiling point." 
 
 "Does this latent heat burn you as much as the other kind 
 of heat?" said Pierce. 
 
 'Try it and see," replied McAndrew. "If you stick your 
 hand in water at the boiling temperature I don't believe you 
 will care whether the heat is 'sensible' or 'latent.' " 
 
 "If he's sensible I think he will keep his hand out of it," 
 broke in the irrepressible O'Rourke. 
 
 "Now," continued the instructor, "you have sometimes 
 heard the expression 'saturated' steam, and I suppose you 
 think that something must have been mixed with it; but that 
 is not the meaning at all. It really means steam in its natural 
 condition; that is, for every pound pressure on the boiler 
 there is a certain temperature corresponding." 
 
 O'Rourke whispered to Schmidt, "I'm on ; now I know why 
 they say a man is 'saturated,' like that drunken oiler we had 
 last trip; it was his natural condition all right." 
 
 "If more heat is added to the steam than is due to that 
 of its pressure then we have what is known as 'superheated' 
 steam ; and people are waking up to the fact nowadays, after 
 discarding the use of superheated steam years ago, that there 
 is real economy in it. I think that before long you will see 
 nearly all marine engines using superheated steam. 
 
26 MC ANDREW'S FLOATING SCHOOL 
 
 "If the steam was generated under an atmospheric pressure 
 only, a cubic inch of water would form 1,663 cubic inches of 
 steam. To memorize that fact keep in mind that a cubic inch 
 of water will make nearly i cubic foot of steam. Don't follow 
 that rule too strictly, or some time you may be as badly off 
 as the old lady who, when asked for a pound of shot and not 
 having any scales, remembered the old rule, 'A pint's a pound 
 the world around/ and gave the purchaser a pint of shot. 
 Right here let me warn you about using these old approximate 
 rules too freely unless you really understand why they are 
 used and know the correct ones. Engineering is an exact 
 science, and it does not pay to guess at anything. 
 
 "Steam, however, is not generated in boilers under atmos- 
 pheric pressure; therefore I want you to know that while 
 water, will begin to boil at a sensible heat of 212 degrees when 
 the steam is unconfined, as the pressure rises, the boiling point 
 is raised correspondingly. Thus at 20 pounds pressure it will 
 not boil until the temperature is 228 degrees, at 50 pounds 
 pressure at 281 degrees, at 160 pounds at 363.6 degrees, and so 
 on. Perhaps I should tell you here that the pressures I have 
 given are what are known as absolute pressures, and I sur- 
 mise that you do not know what that term means. It prob- 
 ably has never occurred to you that air weighs something; 
 you breathe it and move through it as if it did not cause any 
 particular resistance, but the pressure is there just the same. 
 Now to understand it you must consider that the atmosphere 
 we move around in is similar to water ; the deeper you go in 
 it the greater is the pressure, but as we are generally at the 
 bottom of the air, which is at the level of the sea, we 
 usually have the greatest pressure attainable, and it amounts 
 to 14.7 pounds per square inch. In some foreign countries 
 they speak of the pressure on the boiler not as so many pounds 
 per square inch but as so many 'atmospheres.' Thus a pressure 
 of 10 atmospheres, you can quite readily understand, is ten 
 
HEAT, COMBUSTION AND THE GENERATION OF STEAM 27 
 
 times 14.7 pounds, or 147 pounds gage pressure. If you were 
 at the top of a high mountain, the air pressure would not be 
 so great and water would boil at a less temperature than 212 
 degrees. The steam gages on a boiler always record the 
 pressure above the atmosphere; hence to find the absolute 
 pressure of steam you must add to the apparent pressure 
 shown on the steam gage the constant 14.7. This is important 
 for you to remember, for later on when we get to talking 
 about pressures in triple-expansion engines and turbines you 
 must forget about steam-gage pressures and deal in absolute 
 pressures." 
 
 "How is it," asked Schmidt, "that this atmospheric pressure 
 don't crush in our ribs?" 
 
 "That's a good question," replied the Chief, "and I'll answer 
 you by asking you one. How is it that a thin box without a 
 lid on, sunk at the bottom in 25 feet of water, is not crushed 
 by the water pressure? I'll also tell you the answer, and that 
 is because the water is on both sides of the walls of the box, 
 and it is consequently balanced. So with the human system, 
 we breathe air and get it inside of us and there is a balance. 
 Now if that thin box had a lid on it and was watertight the 
 sides would be crushed by the water pressure." 
 
 "Gee!" interrupted O'Rourke, "I'll keep my lid off after 
 this ! I don't want my sides crushed in !" 
 
 "No danger of that," retorted Schmidt. "You are not 
 watertight you've got a leak in -your throat." 
 
 "Following this discussion on the pressure of air, we might 
 as well take up the question of Vacuum' and get a good idea 
 of that. O'Rourke, what do you understand is meant by 
 a 'vacuum'?" 
 
 "Why er let me see," replied the talkative one. "Why 
 er it's something in the condenser that sucks in your hand if 
 you put it over the air cock." 
 
 McAndrew smiled and said, "No; it is something that is 
 
28 MC ANDREW'S FLOATING SCHOOL 
 
 not in the condenser, and your hand is not 'sucked in' but 
 forced in by the pressure outside ; otherwise, O'Rourke, your 
 answer is excellent. You made two guesses and got them 
 both wrong. You might have gone further in your lucid 
 description and said that it was something which smelled bad. 
 The term vacuum really means the absence of air, or the 
 absolute zero of pressure. I have just told you that the air 
 under normal conditions, at the level of the sea, weighs 14.7 
 pounds per square inch. Now if you pump out all the air from 
 a box or other receptacle there is no pressure in it because 
 there is no air. If a small amount of air is allowed to rush 
 in there will be, naturally, a small pressure, but how much? 
 That is what we want to know, as there must be some means 
 of measuring it. You all have learned undoubtedly that this 
 ship carries 26 inches of vacuum when we are running. That 
 comes from the fact that some early scientific fellow learned 
 by experiment that the pressure of the atmosphere (14.7 
 pounds per square inch) was the same as the weight of a 
 column of mercury, or quicksilver, as you may know it, 29.74 
 inches in height. In other words, a perfect vacuum, or the 
 absence of all air in a condenser, would be shown on the 
 vacuum gage as 29.74 inches. If a small amount of air be 
 admitted the needle on the gage would show a vacuum of 
 less than that, as the balance between the air and the mercury 
 would be disturbed. Finally, if the condenser was opened so 
 that air could rush in freely, the needle would go back to the 
 zero mark. It is customary, therefore, to speak of carrying a 
 vacuum of so many inches, but don't ever speak of having a 
 vacuum of over 30 inches, or people will think you are foolish. 
 As a matter of fact, it is quite difficult on ordinary ships to 
 get a vacuum much over 28 or 28;^ inches. As 2 inches of 
 vacuum is equivalent to I pound of pressure you can see how 
 valuable it is for the working of the engine to have as great a 
 vacuum as possible. 
 
HEAT, COMBUSTION AND THE GENERATION OF STEAM 2Q 
 
 "While on the subject of vacuum, it will be well for us to 
 take up the subject of how far a pump will lift water. After 
 all this is very simple, as the pump does not lift the water at 
 all; it simply pumps out the air, and the air pressure from 
 without forces the water up the suction pipe. On the same 
 principle as the column of mercury, it has been determined 
 that the unit weight of air (the atmospheric pressure) will 
 sustain the weight of a column of water about 33.5 feet in 
 height, and that is the maximum height that water can be 
 lifted by a pump, so never try to pump water through a suction 
 pipe any higher than that. You can force it to almost any 
 height necessary, but you can't lift it any higher than 33.5 feet. 
 There is an old saying that 'Nature abhors a vacuum." It is 
 not sp much an abhorrence as it is the universal tendency of 
 Nature to maintain things in an equilibrium or balance. If 
 you disturb this balance by removing the air from anything, 
 the outside air, water or whatever medium it is, will rush in to 
 restore the equilibrium." 
 
 Just then, Pierce, who had been leaning back in his chair, 
 intensely interested in what was being said, fell over back- 
 wards, much to the amusement of O'Rourke, who remarked, 
 'There she goes again ; Nature is restoring his balance !" 
 
CHAPTER V 
 
 Engineering Materials 
 
 McAndrew, feeling somewhat encouraged at the interest 
 which his class had shown during his remarks on elementary 
 principles, decided that the next step in order would be to 
 give them an idea of engineering materials, so he opened his 
 remarks by saying: "Boys, what material is a cold chisel made 
 from ?" Three of them answered promptly, "Steel, sir/' 
 O'Rourke dissented somewhat by saying that he thought the 
 one he had been using that day must have been made of lead, 
 as he had to grind it so often. Paying no attention to the 
 sally, the engineer pedagogue said : "Well, what is the differ- 
 ence between steel and iron?" As a deep silence followed the 
 question, he remarked : "I thought you didn't know, and that's 
 the reason I asked you. Since you have, I hope, absorbed a 
 few ideas about elementary principles in engineering, I want 
 to drill into you some idea of the materials used in building 
 marine machinery. 
 
 "The first and most important of them is iron, man's most 
 valuable metal." "What about gold, sir?" interjected 
 O'Rourke. "I'm glad you spoke about that, as it shows that 
 you think what most other people do. As a matter of fact, 
 we could get along very well without gold, but we would have 
 hard sledding to get along without iron. Gold is only valuable 
 because of its scarcity, while iron is valuable on account of 
 its usefulness. Luckily, it is found in great quantities in 
 
ENGINEERING MATERIALS 3! 
 
 almost all parts of the world, and as it would be practically 
 impossible to build marine machinery without it, we will 
 try and see what cast iron really is. 
 
 "Since the days of old Tubal Cain, iron has been mined and 
 utilized by mankind for all kinds of implements. It exists 
 in a number of different combinations known as ores, some 
 containing as high as 75 percent of pure iron. The first 
 process after it is taken from the ground is to separate the 
 iron from the other substances, and this is done in what 
 are known as blast furnaces. The scheme is to mix the iron 
 ore with coal or other fuel and melt the whole mass down by 
 means of forced combustion of the coal, hence the term 'blast 
 furnace.' The molten iron being heavier than the other sub- 
 stances, is drawn off at the bottom of the furnace, and being 
 liquid is run along channels in a bed of sand, known as the 
 pig bed, into depressions or molds in the sand about 3^2 feet 
 long, 6 inches wide and 4 or 5 inches deep. When these are 
 cold they are known as 'pigs,' and thus we have the raw mate- 
 rial known as pig iron. 
 
 "Pig iron, of course, varies in quality, as it is affected 
 largely by the impurities of the coal, such as sulphur, silicon, 
 etc., which get mixed with it during the melting process. 
 In olden days, before wood became so scarce, and there were 
 no Pinchots to say 'Woodman, spare that tree,' iron ore was 
 melted down with charcoal, and consequently not so many 
 impurities entered into the pig iron. That metal was then 
 known as charcoal iron, and you can yet hear old timers 
 bemoan the fact that they get so little of it these days. 
 And it is a fact that genuine charcoal iron is now very scarce 
 indeed. However, we get along quite well without it by hav- 
 ing learned to make steel better and cheaper than the pioneers 
 could. 
 
 "Now that you know something about cast iron, we will 
 see for what purposes it is used on board ship. You all 
 
32 MC ANDREW S FLOATING SCHOOL 
 
 probably know that the cylinders are made of cast iron, 
 always have been and always will be, as it cannot be improved 
 upon for the purpose. It has sufficient strength to withstand 
 the strain, will not melt or change under the heat, is readily 
 machined, can be made into almost any form, becomes very 
 smooth on wearing surfaces, and, above all, is very reason- 
 able in price. That combination of qualities can never be 
 excelled by any known metal." 
 
 "How strong is cast iron?" said Pierce. 
 
 "That's a good question," was the reply. "As I told you 
 before, everything to be measured must have some standard 
 of comparison. In the case of cast iron, the usual standard 
 is what is known as its tensile strength per square inch. That 
 means the number of pounds it would take to pull a bar 
 one inch square, or one square inch in section, until it breaks. 
 It is placed in a testing machine, which works very much on 
 the principle of a beam weighing machine, and the weight 
 or strain is gradually applied until the test piece breaks in 
 two. The strength of the metal varies according to its quality 
 and treatment, and its quality usually depends on the amount 
 of impurities contained in the metal. 
 
 "First-class iron, such as used in cylinders, frequently has 
 a tensile strength between 25,000 and 30,000 pounds per square 
 inch. Other and poorer grades, such as are used in grate 
 bars, furnace fittings, etc., have a strength of only 10,000 to 
 15,000 pounds to the square inch. 
 
 "Rigidity is the main feature of cast iron, and other tests, 
 such as crushing and bending, are given to it, yet for all prac- 
 tical purposes the marine engineer is satisfied to know that it 
 has the required tensile strength, as that is generally a guar- 
 antee that it will withstand any crushing or bending strains 
 that will be placed upon it. 
 
 "Bedplates and condenser shells or walls are made of cast 
 iron of fairly good quality, but need not be of such good 
 
ENGINEERING MATERIALS 33 
 
 material as that used for the cylinders. Guides, pistons, etc., 
 are usually made of the best quality of iron. 
 
 "What is wrought iron, did you say ? That's something you 
 hear about, but very seldom see these days. Strictly speaking, 
 wrought iron is literally pure iron, or iron with all other 
 ingredients removed. Before we knew so much about steel 
 making there were large quantities of wrought iron used about 
 a ship; in fact, the ship's hull itself was built of it. The 
 process of making it was to melt cast iron in what was known 
 as a reverberatory furnace that is, a furnace where the iron 
 came in contact with the flame but not the fuel. By this 
 means the carbon, etc., was burned out of the molten mass as 
 well as could be, and men called puddlers stuck a bar into 
 the boiling iron, rolled up a ball of it, like you would taffy, 
 put it under a squeezer or hammer to squeeze out the dro.ss, 
 then either hammered or rolled it out into bars or sheets. 
 This material could be forged, welded or rolled into almost 
 any shape desired. The process of its manufacture was slow 
 and expensive, and it has now been practically abandoned. 
 
 "Before I go any further I want to impress upon you the 
 main distinction between cast iron, wrought iron and steel. 
 Remember these fundamental facts and you will have the 
 general idea: 
 
 "i. Wrought iron is pure iron with very little or no carbon 
 in it. 
 
 "2. Steel is pure iron mixed with from one-tenth of one per- 
 cent to sometimes one and two-tenths percent of carbon, ac- 
 cording to the grade of steel required. 
 
 "3. Cast iron is iron mixed with about 3 1 A percent of carbon, 
 and with certain combinations even a higher percentage than 
 that. 
 
 "You will thus see that the main distinction between these 
 different grades of material is the amount of carbon they con- 
 tain. To be sure, there are other ingredients in the mixture, 
 
34 MC ANDREW'S FLOATING SCHOOL 
 
 such as sulphur, manganese and silicon in varying quantities. 
 Sulphur is always bad, but certain small amounts of man- 
 ganese and silicon are beneficial." 
 
 "What is this malleable iron we hear about?" inquired 
 Pierce of the instructor. 
 
 "Malleable," replied McAndrew, "means capable of being 
 hammered or rolled into shape, and although it sounds very 
 good when applied to cast iron, you don't want to hammer it 
 too vigorously or you will find that it will take the shape of 
 two or three separate pieces, such as that two-inch elbow I 
 saw O'Rourke wrestling with this afternoon." 
 
 "I didn't think you was looking when I busted that elbow," 
 replied the guilty one. 
 
 "I saw it all right, and let that be a lesson to you that all 
 malleable iron is not as 'malleable' as you might imagine. 
 
 "In making iron castings malleable, they are packed in 
 some substance, such as mill scale or sand which will not 
 melt, heated to red heat and allowed to stand for a number 
 of days, during which time some of the carbon is withdrawn 
 from the surface of the castings, which to a certain extent 
 makes them tougher and more ductile. This process is used 
 principally for small castings, such as pipe fittings. Some 
 people claim that malleable iron can be welded ; so, to demon- 
 strate whether that claim is true or not, I'll have O'Rourke 
 weld up that elbow he broke." 
 
 "Gee! I wish you would let me buy a new one instead," 
 pleaded the Irish lad. "I'm not much on this scientific dope." 
 
 "To return to the subject," said McAndrew, "we will next 
 take up the subject of steel, as used for shipbuilding. 
 
 "There are two principal processes used in the manufacture 
 of structural steel, the Bessemer and open-hearth. As Bes- 
 semer steel is not used in any part of a ship, it will suffice to 
 discuss the open-hearth process. 
 
 "This consists essentially of melting pig iron, scrap steel and 
 
ENGINEERING MATERIALS 35 
 
 wrought iron in a large circular furnace, sometimes as large 
 as 20 feet in diameter, the heat being furnished by the com- 
 bustion of gas over the top of the metal, so that, unlike a 
 blast furnace, the fuel does not come in contact with the 
 metal. This results in burning out the carbon in the mixture 
 to a degree slightly less than that required in the steel to be 
 made. In order to get the exact proportion of carbon re- 
 quired in the mixture, a certain amount of 'spiegel-eisen' is 
 added." 
 
 "What's that, sir?" inquired O'Rourke. 
 
 "Ask your German friend," replied McAndrew. 
 
 "I don't know just what 'spiegel-eisen' is," replied Schmidt, 
 "but in German it means looking-glass iron." 
 
 "That's right," said the instructor. "It gets its name from 
 its bright surface, and it is really an iron ore containing a 
 large proportion of manganese. This manganese unites with 
 the oxygen and sulphur in the mixture and removes them. 
 Spiegel-eisen also adds the requisite amount of carbon to the 
 mixture. After it is determined by the man in charge of 
 the furnace that the desired mixture is reached, the molten 
 steel is run into ladles, from which it is poured into large 
 molds which shape the metal into huge blocks of steel known 
 as ingots. These ingots are, when needed, heated in a fiery 
 retort to almost a white heat, and run back and forth through 
 rolls until they are shaped into what are known technically as 
 slabs and billets. In that shape they are selected to fill orders 
 for boiler or ship plates and engine forgings, such as shafting, 
 piston and connecting rods, columns, valve stems, etc." 
 
 "How can you tell this open-hearth steel from wrought 
 iron?" inquired Nelson. 
 
 "Easy enough," interjected O'Rourke, "ask the man you buy 
 it from!" 
 
 "That would be all right," said McAndrew, "if he knew the 
 difference himself. As a matter of fact, it is very difficult 
 
36 MC ANDREW'S FLOATING SCHOOL 
 
 to tell from appearances. Some people claim that they can 
 tell by looking at it, but I have my doubts as to that. Others 
 who are expert in working iron and steel can be reasonably 
 sure by the way they cut. I remember once of being in doubt 
 whether a certain lot of boiler tubes were of wrought iron 
 or mild steel, and I could find no one who was absolutely 
 sure as to the material of which they were made. There is 
 one infallible way, however, of telling, and that is by cutting 
 the metal in two, polishing up the surface and pouring on a 
 little nitric acid. In wrought iron there is bound to be a 
 certain amount of slag in the mixture which strings out in 
 the rolling process and gives the metal the appearance of hav- 
 ing a grain. When nitric acid is applied, the pure iron is eaten 
 away and leaves the grain sticking above the surface. Steel 
 being practically a homogeneous metal is eaten away uni- 
 formly by the acid. 
 
 "The next most important metal for marine machinery is 
 brass, and I'll ask O'Rourke to tell you what it is." 
 
 Clearing his throat and assuming an air of importance at 
 being called upon for an expert opinion, the son of Erin 
 replied: "Brass is a metal that is mined I don't know jnst 
 where ; it costs like blazes, smells bad, is 'pisonous' to the skin, 
 gets dirty in five minutes, and is used around an engine room 
 principally for the purpose of keeping the poor firemen busy 
 shining it up when they ought to be resting themselves." 
 
 "That certainly is a very lucid description, and coming from 
 such an expert on 'brass' it will have great weight. How- 
 ever, I cannot agree with all your conclusions, and especially 
 as to its being mined. 
 
 "Brass, as it is commonly termed, is not an elementary 
 metal, as it is composed of two and sometimes three ele- 
 ments, such combinations of two or more metals being known 
 generally as alloys. An alloy composed of copper and zinc, or 
 
ENGINEERING MATERIALS 37 
 
 of copper, zinc and a very small amount of tin, is known as 
 brass. When a larger proportion of tin or other metal, such 
 as aluminum or lead, is used, the alloy is known as a bronze. 
 As a matter of fact, the terms 'gun metal,' 'composition,' and 
 'bronze' are used rather loosely, and it is hard to draw a line 
 of demarcation between them. 
 
 "The principal reasons for using brass, composition, bronze, 
 etc., in the construction of marine machinery are their de- 
 creased friction when rubbed on other metals, their freedom 
 from oxidization or corrosion, as it is commonly called, and 
 in some instances for ornamentation. The latter reason is 
 growing less every day, as there is plenty of other work on 
 board a modern vessel to keep the firemen busy without having 
 needless brasswork to polish. 
 
 ''There are about a million different compositions of cop- 
 per, tin, zinc, lead, antimony, iron, aluminum, etc., which can 
 be made, but the principal ones of interest to marine engi- 
 neers are the following, mixed in the proportions given: 
 
 "Common yellow brass: Copper, 65.3; zinc, 32.7; lead, 2. 
 
 "Babbit metal: Copper, 3.7; tin, 88.9; antimony, 7.4. 
 
 "Brazing metal: Copper, 84; zinc, 16. 
 
 "Admiralty bronze: Copper, 87; tin, 8; zinc, 5. 
 
 "Manganese bronze: Copper, 88.64; tin, 8.7; zinc, 1.57; iron, 
 .72 ; lead, .30. 
 
 "Muntz metal: Copper, 60; zinc, 40. 
 
 "Navy composition: Copper, 88; tin, 10; zinc, 2. 
 
 "White metal: Lead, 88; antimony, 12. 
 
 "Phosphor bronze: Copper, 90 to 92; phosphide of tin, 10 
 to 8. 
 
 "Tobin bronze : Copper, 59 to 61 ; tin, I to 2 ; zinc, 37 to 38 ; 
 iron, .1 to .2; antimony, .3 to .35. 
 
 "You probably will never be called upon to mix any of 
 Ihese compositions yourselves, and it is well that you will "not, 
 
38 
 
 as it takes an expert to do it. However, it will do you no 
 harm to know what goes into the various metals with which 
 you will have to deal. 
 
 "There is another alloy which is rapidly coming in use for 
 marine machinery, known as 'Monel metal.' Unlike other 
 compositions, it is mixed by Nature itself, as it is in reality 
 nickel ore just as it is mined. It is composed principally of 
 nickel and copper in about the proportion of 65 to 35. It 
 has been found to be very efficient for valve seats in steam 
 valves where superheated steam is used, for pump rods and 
 valve stems, and for propellers. The tensile strength is 
 equal to that of steel, and it is non-corrosive in salt water 
 and acids. 
 
 "I have now described to you in a general way the prin- 
 cipal materials used in an engine room " 
 
 "You have left the main ones out, Chief !" said O'Rourke. 
 
 "What are they?" 
 
 "Why, the gold and silver that are handed out once a 
 month." 
 
 "You'll have to know a good deal more about steel and 
 brass than you do now before you can connect very strongly 
 with those metals," retorted McAndrew, as he dismissed the 
 class for the evening. 
 
CHAPTER VI 
 
 Boilers 
 
 "We have now covered the most important of the funda- 
 mental subjects which all engineers should know, so we will 
 begin on the subjects relating to the parts you are most in- 
 terested in, that is, those with which you have already had 
 some practice. I will therefore ask you what, in the opinion 
 of each, is the most important thing to take up." 
 
 "Propellers," promptly replied Pierce; "they drive the 
 ships." 
 
 "No, sir," said Schmidt, "let's take up the engines, for they 
 drive the propellers." 
 
 "I think we ought to begin with boilers, sir," remarked 
 Nelson ; "they furnish the steam which drives the engines." 
 
 "Ah!" said O'Rourke, "if that's the reason, let's take up 
 'the walking of the ghost' when he comes across with the 
 money that makes 'em all go." 
 
 "Nelson," said McAndrew, "has the right idea the boilers 
 are the most important parts of marine steam machinery. If 
 you don't get the steam first, no matter how good the engines 
 and propellers may be, the ship will not move. 
 
 "I have already told you what happened when coal is put 
 in the furnaces, and now we want to know something about 
 the boilers that hold the steam after it is made. How many 
 kinds of boilers are there, O'Rourke?" 
 
 "Two, sir," replied that youngster; "tight ones and leaky 
 ones." 
 
40 MC ANDREW'S FLOATING SCHOOL 
 
 "Well, that's a good distinction, but hardly the kind that 
 we want to talk about, although I'll admit that a tight boiler 
 of any description is better than any kind that leaks. If you 
 were to study books on the subject you would have to read 
 descriptions of a dozen types of shell boilers, but as there is 
 practically only one type used on steamers nowadays, any 
 knowledge you might gain about discarded types would be as 
 useful to you as last year's bird nests. The principal type of 
 shell boiler all marine engineers in the merchant service have 
 to deal with now is the Scotch type single or double-ended. 
 By the time you boys get to be chief engineers even that 
 type will probably be put on the shelf, as the day of the use 
 of watertube boilers is fast approaching. However, as the 
 Scotch boiler is just at present the principal one to be con- 
 sidered, we will give that first attention. This boiler is named, 
 probably, from the fact that it was first developed by Scotch 
 shipbuilders, than whom," said McAndrew, .evidently taking 
 pride in his ancestry, "there are no better in the world. 
 
 "Up to the present time it has stood the test of service 
 better than any others of the class of shell boilers, and has 
 consequently lived to see the others discarded. Theoretically, 
 an ideal shell boiler, to withstand internal pressure, would be 
 one shaped like a sphere or ball, as curved surfaces need no 
 bracing; flat surfaces should be avoided in boiler work, and 
 the principal feature of a Scotch boiler, which makes it so 
 efficient, is that there are as few flat surfaces as possible. 
 The shell of the boiler is made cylindrical, the furnaces are 
 cylindrical, as also, of course, are the tubes. Consequently, 
 the only flat surfaces are the heads and portions of the com- 
 oustion chambers. 
 
 "The thickness of the boiler shell depends upon three 
 ihings: the steam pressure to be carried, the diameter of the 
 boiler and the strength of the material used. The steam 
 pressure has gradually been increased, so that now it is not 
 
BOILEF3 41 
 
 uncommon to find Scotch boilers carrying from 200 to 250 
 pounds pressure; the diameter has increased so that boilers 
 16 to 18 feet in diameter are not rare. The time is not far 
 distant when the shells will have to be so thick as to make 
 this type impracticable ; then you will see the watertube boil- 
 ers come into greater use. 
 
 "In the early days of steam machinery, boiler building was 
 a crude art. Compared with modern methods of construction 
 it was in about the same relation as early wooden shipbuilding 
 bears to modern steel shipbuilding. If a ship carpenter made 
 anything that came within a half inch of the dimensions of 
 the stick of timber he was shaping, he was supposed to be 
 quite accurate. Old-time boiler makers were just about as 
 crude;* they rarely had drawings to follow, a rough sketch on 
 a blackboard in the boiler shop sufficing; holes were always 
 punched, and the drift-pin was used almost continuously. 
 While such methods were all right for boilers using low steam 
 pressures, they would not do nowadays at all. With the 
 high steam pressures now used, and the large size of the 
 boilers, nothing but accurate design and good workmanship 
 will do. In the early days of boiler construction all rivets 
 were driven by hand ; now nearly all rivets are driven by 
 hydraulic pressure of 15 to 30 tons, and even with that it is 
 almost impossible to keep some of the seams and rivets from 
 leaking. 
 
 "Here is a drawing (Fig. i) of a typical small Scotch 
 boiler which will show the general features of this type. 
 It consists essentially of four steel plates rolled up into the 
 form of a cylinder which is known as the shell of the boiler. 
 Each portion of the shell is known as a course. The courses 
 are lapped over one another and riveted together by what 
 are known as lap joints. The. longitudinal seams come 
 together and are joined by straps or narrow plates on the 
 inside and outside, the whole when riveted together being 
 
42 MC ANDREW S FLOATING SCHOOL 
 
 known as a butt-joint. In this shell are two, three, or some- 
 times four smaller cylindrical furnaces which are riveted to 
 the combustion-chamber, a semi-cylindrical box with flat top, 
 front and back, in which the combustion takes place. 
 
 "You will notice that these furnaces are not straight, but 
 consist of a wavy contour. In this particular case they are 
 known as suspension furnaces. Some of them have a series 
 
 FIG. 1. SCOTCH BOILER. END VIEW 
 
 of corrugations rolled into them, the object of both types 
 being to give them sufficient strength to withstand the crush- 
 ing strain brought upon them by the pressure of the steam. 
 It is much easier for a cylindrical tank or figure to withstand 
 an internal or bursting pressure than it is for it to withstand 
 an external or collapsing pressure, hence all furnaces (in 
 Scotch boilers) subjected to high pressures of steam on the 
 
BOILERS 
 
 43 
 
 outside must be corrugated in order that they will not col- 
 lapse under the pressure. 
 
 "From the combustion chamber to the front head are a 
 number of small tubes, usually from 2 inches to 4 inches in 
 diameter, through which the hot gases pass from the furnaces 
 to the uptake and thence to the smoke stack. It is from these 
 tubes where the greater portion of the steam is formed, as 
 
 FJG- 2. SCOTCH ROILER, LONGITUDINAL SECTION 
 
 they are usually from 1/16 to % inch in thickness, so that 
 the heat from the gases is very readily transmitted to the 
 water which surrounds them. 
 
 "As the heads of the boiler and the larger part of the com- 
 bustion chambers are flat, they must be supported or braced at 
 intervals in order that they may withstand the pressure 
 brought upon them. Later on, I will teach you how to space 
 
44 MC ANDREW'S FLOATING SCHOOL 
 
 these braces or stays, as they are termed, as that is a question 
 which will be asked before you can get your licenses. 
 
 "In the furnaces of a Scotch boiler the grate bars are 
 arranged at about the middle at the front end and slope 
 slightly downwards toward the back end. The length of 
 the grates is generally about 6 feet, as that is about as far as 
 a good husky fireman can work his fires properly. Sometimes 
 they are $ l / 2 feet or 6 T / 2 feet long, but in general you will find 
 them averaging 6 feet in length. The capacity of the fireman 
 in this respect really regulates the length of most Scotch 
 boilers. Hence you will find that single-ended boilers very 
 seldom exceed n or 12 feet in length, while double-ended 
 boilers are generally about 20 to 22 feet in length a double- 
 ended Scotch boiler being practically two single-ended Scotch 
 boilers placed back to back and joined together. As I said 
 before, there are a number of other types of shell boilers, but 
 as most of them are obsolete, we will not waste any time on 
 them." 
 
 "What's obsleet?" inquired O'Rourke. 
 
 " 'Obsolete' means old-fashioned, not up-to-date," replied 
 the instructor. 
 
 "I see," replied O'Rourke; "it's something like that hat 
 Schmidt wears when he goes to see his girl in Fishtown." 
 
 "We will now look into the watertube boiler question a 
 little. This type of boiler is having a hard time in overcom- 
 ing the prejudice against it. At first they were used in swift 
 steam launches and torpedo boats, on account of the great 
 saving in weight as compared with shell boilers. Old-time 
 engineers viewed them as a sort of a necessary evil in that 
 respect and pitied the men who had to run them. The battle 
 for supremacy in speed between the various nations finally 
 led the more daring designers to use them in some swift 
 cruisers and gunboats. As no great harm seemed to have 
 come of this, the more progressive designers finally adopted 
 
BOILERS 4,- 
 
 this type of boiler for battleships. Old-timers shook their 
 heads at this move and predicted dire disaster for the ships 
 thus equipped. However, the results have been so satisfactory 
 that to-day every new battleship throughout the world is fitted 
 with watertube boilers, and they are giving the greatest satis- 
 faction on account of their many superior qualities. 
 
 "O'Rourke, you of course know something about watertube 
 boilers; how many classes of them do you think there are?" 
 "I don't know much about them myself," replied the young 
 man, "but I heard a fellow out in the shipyard say to-day 
 that there were two kinds, the macaroni and the spaghetti, 
 whatever they mean." 
 
 "Ha ! Ha !" laughed McAndrew. "I suppose he meant 
 'macaroni' boilers were those with large straight tubes, and 
 'spaghetti' as those having small, bent tubes. That is rather a 
 good definition for the two main divisions of this class of 
 boilers, but so far as different designs are concerned there 
 must be two or three hundred, as every designer has his own 
 ideas about getting up a watertube boiler. But these various 
 kinds of boilers remind me of what they say about the fish in 
 the waters around the Hawaiian Islands there are 298 varie- 
 ties, but they only use three of them to eat. 
 
 "In general, the main difference between Scotch and water- 
 tube boilers is that in the former the hot gases are inside the 
 tubes and the water around the outside, while with the latter 
 the water is inside the tubes and the gases around the out- 
 side. 
 
 "Watertube boilers usually consist of drums, headers and 
 tubes, all inclosed in sheet metal casings. Usually there are 
 one or two large drums on top and two or more smaller drums 
 at the bottom, the tubes connecting the drums at the top and 
 bottom. The feed water usually enters the boiler in the top 
 drum, and is carried down to the lower drums through tubes 
 or pipes known as down-flow tubes. Sometimes it flows down 
 
46 MC ANDREW'S FLOATING SCHOOL 
 
 through the tubes themselves. In any event a rapid circula- 
 lation is started up between the water in the lower and upper 
 drums or headers. As the water passes up through the tubes, 
 globules of steam are formed which, discharging into the 
 upper drum with the water, are separated by baffle plates 
 from the water and pass out through the dry pipe into the 
 main steam pipe. The tubes in which the steam is formed are 
 known as generating tubes to distinguish them from down- 
 flow tubes when such are fitted to the boiler. Watertube boil- 
 ers are usually rectangular or box-shaped, as the casing sur- 
 rounds the tubes and the furnaces. In order to prevent the 
 sheet metal casing from burning, it is usually lined with 
 asbestos board and fire brick. Large tube boilers are those 
 which have generating tubes 3, 4 or sometimes 5 inches in 
 diameter. Boilers built of tubes i to 2 inches in diameter are 
 classed as small tube or 'spaghetti' boilers, as O'Rourke's 
 friend would say. 
 
 "Some engineers prefer one type and some the other, but 
 if I had anything to say about fitting watertube boilers to a 
 merchant vessel, the tubes would be as large as practicable 
 and straight or nearly straight, so that they can be cleaned 
 and examined." 
 
 "Why don't shipowners use watertube boilers in merchant 
 vessels?" inquired Nelson. 
 
 "That's hard to answer," replied the Chief, "but I suppose 
 it is for the same reason that many people refused to ride on 
 the elevated road when it was first constructed in New York. 
 They had been brought up to ride in corse cars on the streets : 
 they knew they were safe and sure, and although they could 
 ride faster on the elevated, they preferred the safety which 
 they knew of, rather than to take a chance on the more mod- 
 ern means of transportation of which they were afraid. Such 
 a trait of mankind is known as conservatism, and it is an 
 
BOILERS 
 
 47 
 
 excellent quality until it is carried to excess, when it becomes 
 foolishness. 
 
 "The advantages watertube boilers have over Scotch boilers 
 are many. The weight of a watertube boiler, with water, is 
 just about one-half that of a Scotch boiler under the same 
 conditions, thus giving that much more cargo-carrying ca- 
 pacity. Steam can be raised in a half hour, as compared to 
 four to six hours for raising steam in a Scotch boiler. There 
 is less danger from a serious explosion, as the parts of a 
 watertube boiler liable to explode are much smaller than the 
 great bulk of a Scotch boiler, under pressure. 
 
 "A watertube boiler need never wear out entirely, as the 
 various parts can be renewed as necessity requires. When a 
 Scotch boiler wears out, it must be renewed in its entirety, 
 and generally at great expense on account of tearing away the 
 decks and joiner work above the boiler space. 
 
 "Watertube boilers can be forced much harder, with safety, 
 than Scotch boilers, as they are in a manner flexible and can 
 stand severe usage which ordinarily starts a Scotch boiler 
 leaking. 
 
 "One of the main features which would appeal most, just 
 now, to you boys, is the matter of cleaning. In watertube 
 boilers there are no back connections to sweep a task which 
 makes the life of an old-time chimney-sweep seem easy in 
 comparison no crown sheets to clean and sometimes scale, 
 no cleaning of the inside of the boiler, where a man must go 
 through contortions like a ferret to get at the heating sur- 
 faces. I doubt if any more disagreeable job could have been 
 devised in the days of the Inquisition than that which befalls 
 the lot of a marine fireman when it is boiler cleaning time on 
 board a ship fitted with Scotch boilers. Surely there is 
 nothing which more discourages men from going to sea. No 
 wonder engineers hurry and get fat as soon as possible, so that 
 it is a physical impossibility for them to get through a 12 by 
 
48 MC ANDREW'S FLOATING SCHOOL 
 
 15 inch manhole. If the stokers and coal passers could vote 
 on the type of boiler to be used, I am afraid the Scotch boiler 
 would soon get in the class with Schmidt's hat. 
 
 "The disadvantages claimed by opponents of watertube 
 boilers are that it takes more skill to tend the feed on ac- 
 count of the smaller quantity of water in the watertube type. 
 This, I am told, is more imaginary than real, although it 
 must be admitted that a water tender must be onto his job 
 at all times and keep his eyes on the glass. So, too, should 
 a water tender with any other type of boiler, as that is a 
 duty where day dreaming does not go. It is also claimed that 
 strictly fresh water must be fed into watertube boilers at 
 all times, but, as a matter of fact, that is so with a modern 
 Scotch boiler if its efficiency is to be maintained. The care 
 of marine boilers of any type is one of the most important 
 duties on board ship. Carelessness on the part of anyone 
 connected with the handling of boilers is not only dangerous 
 to all on board, but frequently results in large repair bills 
 and operating expenses. The most successful engineers are 
 those who keep the boilers in good condition and operate them 
 intelligently.'* 
 
CHAPTER VII 
 
 Boiler Fittings 
 
 "How many fittings are there on a marine boiler?" inquired 
 McAndrew. 
 
 "Four, sir," said Nelson. 
 
 "Only four, eh? Well, what are they?" 
 
 "The steam gage, gage glass, shovel and slice bar," replied 
 Nelson. 
 
 "Oh ! come off," said O'Rourke, "the shovel and slice bar 
 are what the highbrows call the 'implements of your trade' 
 they're not fittings." 
 
 "Well, O'Rourke," said the teacher, "how many do you 
 think there are?" 
 
 "Oh! at least half a dozen," replied he, "but for the life 
 of me I can't think of their names just now." 
 
 "O'Rourke, you remind me of the fellow who, when falling 
 off the water wagon, paused in the act of taking a drink and 
 said, There are a dozen good reasons why I shouldn't drink 
 this whiskey, but for the life of me I can't think of one of 
 them now' and then he took the drink. I don't think you 
 have tried very hard to think of the necessary fittings on a 
 boiler, but, at any rate, I'll remind you of some of them. 
 
 "You all know of the safety valves, which are generally 
 made in pairs and are bolted to the highest part of the boiler. 
 The old-fashioned safety valves were of the ball-and-lever 
 type, but they are not used to any great extent these days, as 
 they are poorly adapted for high pressures, or in fact for use 
 on shipboard at all. One of the most important duties about 
 
5O MC ANDREW'S FLOATING SCHOOL 
 
 the fireroom is to see that the so-called easing gear for lifting 
 the safety valves off their seats is kept well oiled and in good 
 working condition. At least every other day the valve should 
 be lifted off its seat for an instant to see if the springs are 
 working well. It might be necessary to open the safety 
 valves in a hurry some day, and if the gear is not kept in 
 good condition they would fail at the critical moment. 
 
 "The stop valves on boilers are very important fittings, as 
 they control the passage of the steam to the engines. On 
 every boiler you will find a large valve known as the main 
 stop valve, and a smaller one, the auxiliary stop valve. These 
 valves, too, should have their stems lubricated and kept in 
 such condition that they can be worked easily. In this con- 
 nection I want to warn you young men against opening a stop 
 valve on a boiler suddenly many a good man has gone to 
 Kingdom Come by not bearing that in mind. You must re- 
 member that a sudden release of steam often causes large 
 gulps of water to be carried with the steam through the valve 
 and into the steam pipe, where a water hammer is instantly 
 formed and often with the result of bursting the pipe. Even 
 if no water is carried out with the steam, the pipes are cold, 
 and the sudden condensation results also in a water hammer. 
 When you open a stop valve, just 'crack' it at the start by 
 that I mean to turn the handwheel a mere trifle until you can 
 hear the steam hissing through the slight opening. Then 
 wait until you can count at least 200 before you give it another 
 slight turn." 
 
 "It's too hot up there to be counting very much," inter- 
 jected O'Rourke. 
 
 "Yes, but it isn't nearly so hot up there as the place you 
 might go to if you opened the valve suddenly," said Mc- 
 Andrew. 
 
 "We have seen how to get the steam out of a boiler, but 
 after all it is of even greater importance to get the water into 
 
BOILER FITTINGS ej; 
 
 it, for if you fail to keep the water flowing into a boiler under 
 steam, there would soon be something doing. 
 
 "Schmidt, do you know what a check valve is?" 
 
 "No, sir," replied he, "I don't know just what it is, but I 
 know where it is, and I know that you open it to let the water 
 in the boiler after you start the feed pump." 
 
 "That's something to know," continued McAndrew, "but 
 like a certain brand of breakfast food, 'there's a reason for 
 it.' A check valve is one which allows water to pass in only 
 one direction that is, from the pump to the boiler. It is 
 made that way so that in case the feed pipe should burst, the 
 scalding hot water and steam from the boiler would not rush 
 out through the opening in the feed pipe." 
 
 "I'm on," said O'Rourke, "it's like a one-way ticket to 
 Coney Island you can get down there all right, but you can't 
 get back if you blow in all your money." 
 
 "Recently all marine boilers were required to have two 
 separate openings in the shell and two separate check valves, 
 a* main and an auxiliary, to regulate the admission of the 
 feed water, so that if one gives out the other can be used. 
 There is also a stop valve located between the check valve and 
 the boiler shell, so that in case of accident to the check valve 
 the stop valve can be closed and repairs made to the check. 
 It pays to take every possible precaution in regard to such an 
 important matter. 
 
 "After we have provided means for getting ihe water in 
 and the steam out of a boiler, the next thing in importance 
 is to have some way to ascertain the level or height of the 
 water in the boiler. Here, too, every precaution must be 
 taken, for it is a very serious matter. You all have seen the 
 gage glasses and how careful the water tenders are to watch 
 the level of the water in them. The gage glass is, therefore, 
 the most important of the means employed for determining 
 the water level. As a further precaution, there are four gage 
 
52 MC ANDREW S FLOATING SCHOOL 
 
 cocks usually fitted on the side or in the front of the boilers 
 at about the desired water level. I must confess that it i: 
 very difficult for anyone, except a locomotive engineer, tc 
 tell exactly the water level by means of these cocks. It takes 
 a trained eye and a trained ear to distinguish between the 
 steam and water when a ship is rolling. The locomotive engi- 
 neer has to depend on gage cocks almost entirely, as it is 
 impracticable to fit gage glasses on a locomotive. On board 
 ship the men rely almost entirely on the gage glass, so they 
 do not get much practice with the try cocks. I would rather 
 take my chances by having two gage glasses fitted, as it is 
 almost certain that both glasses will never be broken or out 
 of order at the same time. 
 
 "I suppose you have noticed that toy safety valve just over 
 the uptakes on our boilers. If you didn't see the main safety 
 valves, you 'might get the idea that the boiler designer had 
 put a boy to do a man's work. The object of this little valve, 
 which should always be a lever valve with a sliding weight, 
 is to give warning that the steam is almost up to the blowing- 
 off point; hence it is known as a sentinel valve. If for any 
 reason the springs in the safety valve refuse to work, this 
 little valve is sometimes very useful. 
 
 "You, of course, have heard of the blow valves on the 
 boilers. These are usually fitted to all boilers ; one is known 
 as the 'surface blow' and the other as the 'bottom blow.' In 
 boiling water the lighter impurities, such as grease and other 
 substances, which float on water, are driven to the surface of 
 the water. O'Rourke, I know, has often watched his mother 
 skirri the grease off the top of the boiling pot of soup, when 
 he was a boy and was so hungry he could hardly wait for 
 dinner time. The idea of the surface blow on a steam boiler 
 is about the same, only in a boiler there is a pipe connecting 
 the blow valve to what is known as a 'scum pan,' usually 
 located in about the center of the boiler and at about the low- 
 
BOILER FITTINGS 
 
 53 
 
 water level. At intervals it is advisable to open the surface 
 blow valve and give it a slight blow in order to remove the 
 grease and other floating impurities from the boiler water. 
 
 "The bottom blow valve is located at the lowest part of the 
 boiler, and there is usually a perforated iron pipe connected 
 to the blow valve. Mud and heavy impurities collect at the 
 
 FIG. 3. BOURDON STEAM GAGE 
 
 bottom of the boiler, and an occasional blow will remove such 
 substances. This bottom blow is sometimes used to pump out 
 the boiler when it is desired that it be emptied. 
 
 "One of the most important of the so-called 'boiler fittings' 
 is the steam gage, for it is by means of this instrument that 
 we are enabled to determine the actual pressure of the steam 
 in the boiler. 
 
 "Fig. 3 is a picture of the type of steam gage usually fitted 
 to marine boilers. By means of a circular tube having an ellip- 
 tical section as shown, when the pressure is applied to the 
 
54 MC ANDREW S FLOATING SCHOOL 
 
 inside of the tube it tends to assume a round section, and the 
 tube itself tends to straighten out owing to the greater area 
 subjected to pressure on the outside surface. The free end 
 of the tube is connected by gear wheels and pinions to the 
 needle on the face of the dial which, when properly adjusted, 
 records the steam pressure. Remember, as I have called to 
 your attention before, boiler gages only record the pressure 
 above the atmosphere and not the absolute pressure. 
 
 "Steam gages on boilers should be tested at intervals to see 
 that they are adjusted correctly, as it frequently happens that 
 gages on different boilers, all connected up, show a variance 
 of from i to 10 pounds. I once had a green fireman with me 
 who nearly broke his back trying to get the steam on his 
 boiler up to the same pressure carried by the other boiler ; 
 as a matter of fact, the gage on his boiler recorded 5 pounds 
 less pressure, due to its being out of adjustment. The older 
 firemen let him hustle for a day or so before they told him 
 the gage was wrong." 
 
 "Why do they always put that crook in the pipe to the steam 
 gage?" inquired Nelson. 
 
 "That's because most water tenders are so used to seeing 
 snakes that they want things to look natural to them when 
 they watch the steam gage," volunteered O'Rourke. 
 
 "O'Rourke is as nearly right as usual," replied McAndrew. 
 "The real reason is that if the steam acted on the Bourdon 
 tube direct, the expansion due to the varying temperatures 
 would make it record inaccurately. Hence, the crook serves 
 the purpose of a trap, as it fills with water by the condensa- 
 tion of the steam, and this water is forced into the tube by 
 the steam. 
 
 "Another important fitting is the air cock, which is usually 
 placed at the highest part of the boiler. When fires are started 
 this cock should be opened in order that, as the steam is raised, 
 
BOILER FITTINGS 
 
 55 
 
 all the air in the boiler will be driven out. It should not be 
 closed until live steam issues from the cock. 
 
 "To impress upon you the importance of paying attention to 
 even the smallest details around boilers under steam, I want 
 to call your attention to a boiler explosion on board an 
 American vessel not many years ago, when over thirty lives 
 were lost and great damage was done because a fireman who 
 
 FIG. 4. HYDROKINETER 
 
 was sent on top of the boilers to close the air cock not only 
 closed that fitting but also shut off the cock in the small steam 
 pipe which led to the steam gage. The result was that al- 
 though no steam showed on the gage the pressure in the 
 boiler rose to the bursting point and the explosion followed. 
 Always remember that if you make a mistake like that you 
 endanger not only your own life but the lives of everybody 
 else on the ship. 
 
 "Some boilers are fitted with what is known as a 'hydro- 
 kineter/ which means literally a water heater. 
 
 "One of the great faults of all Scotch boilers is that the 
 water under the furnaces and combustion chambers does not 
 circulate properly, or, in other words, it is dead. The hydro- 
 
56 MC ANDREW'S FLOATING SCHOOL 
 
 kineter is usually located in this dead water, and when live 
 steam is admitted it acts on the principle of an ejector and 
 causes the water to circulate as indicated by the arrows in the 
 sketch. I have seen boilers carrying over 100 pounds of 
 steam when you could bear your hand on the bottom of the 
 shell because of the presence of the dead water underneath 
 the furnaces. Some engineers when raising steam will con- 
 nect the auxiliary feed pump so as to draw this cold water 
 out through the bottom-blow connection and discharge it 
 through the auxiliary feed check valve, thus causing an arti- 
 ficial circulation. There are also several very good patented 
 devices for bringing about this much desired circulation. 
 
 "Another item which might be classed as a boiler fitting is 
 the so-called fusible plug which the law requires shall be fitted 
 to the tops of combustion chambers and at other important 
 parts of the boiler. This consists of a brass plug screwed 
 into a tapped hole ; the center of this plug is filled with a soft 
 metal, such a Banca tin, which, when not covered by water, 
 will melt and allow the steam to blow through the opening, 
 thus acting as a safety vent." 
 
CHAPTER VIII 
 Forced Draft 
 
 "Before leaving the subject of boilers, we will look into the 
 matter of forced draft. Although this ship is not fitted with 
 any system for that purpose, many other ships are, so it will 
 be well for you to know about the various methods adopted. 
 
 "I have told you that air is just as important for combus- 
 tion as coal itself. When fires are started in the furnaces the 
 smoke and hot gases go up through the tubes and uptakes to 
 the funnel or stack. You might wonder why they don't come 
 back through the furnace and ash pit doors. The reason why 
 they do not is due to what is known as draft, or the tendency 
 to go up instead of down. Air when heated becomes less 
 dense or lighter in weight, hence it is that at the furnace front 
 and under the grate bars there is a tendency of the air to flow 
 through and up. This tendency is due to the difference in 
 weight of a column of cold air of the height equal to the dis- 
 tance between the level of the grates and the top of the stack, 
 and the weight of a similar column of heated air of the same 
 height. This difference in pressure or weight is usually very 
 slight, but sufficient to cause enough air to flow into the fur- 
 naces to keep up a reasonable rate of combustion. In gen- 
 eral, the higher the funnel the greater the difference in pres- 
 sure, and consequently the better the draft. 
 
 "Draft is usually measured by a device such as is shown 
 in Fig. 5. One end of the U-shaped tube, which is located in 
 the fire-room, is open to the air pressure in the fire-room, the 
 other is connected by a rubber tube to the space under the 
 grates. The difference between the two pressures compels the 
 
MC ANDREW S FLOATING SCHOOL 
 
 water to lower in the free end and rise in the end connected to 
 the tube. We thus speak of draft as measured, not in pounds, 
 but in inches or fractions of an inch of water. Were the pres- 
 sure to be expressed in actual weight, such as a steam gage 
 shows, you would find that i inch of water pressure would 
 equal only two-thirds of an ounce. 
 
 "Ordinarily natural draft on a steamer of this size is about 
 Y^. to y inch of water, and such a pressure under ordinary 
 
 FIG. 5. DRAFT GAGE 
 
 conditions is sufficient to burn enough coal to produce the 
 desired speed of a vessel. There are times, however, when 
 greater speed is demanded than can be produced by natural 
 draft pressures. Fast passenger vessels, steam yachts and 
 torpedo boats must go at full speed either all of the time or 
 at intervals, and under these conditions a greater rate of com- 
 bustion must be obtained. Hence it becomes necessary to use 
 what is termed 'forced' draft, or in other words apparatus 
 for furnishing a greater quantity of air to the furnace than 
 
FORCED DRAFT 29 
 
 would naturally flow in due to the difference in weight of 
 the two columns of air. 
 
 "The most primitive system of forced draft is probably 
 illustrated by the boy who, while shooting firecrackers, blows 
 on a piece of punk in order to make the cracker fuses light 
 easier." 
 
 "Chief," interrupted Schmidt, "I think we could have a good 
 forced draft system on board this ship by making O'Rourke 
 get on his hands and knees and blow under the grate bars; he's 
 about as good a blower as I know of." 
 
 "That's all right," retorted O'Rourke, "about my forced 
 draft ; I know some one not very far off who couldn't be used 
 for that purpose he eats too much Limburger his breath 
 would put out almost any fire instead of making it burn 
 faster." 
 
 "If you young men are running a debating club, we had 
 better quit right here and let you fight it out," said McAndrew. 
 
 "Please go on with the forced draft, Chief," pleaded Pierce, 
 who was by far the most earnest of the Floating School under- 
 graduates. 
 
 "To return to the subject," continued the instructor, "forced 
 draft on board steam vessels is produced by one of four gen- 
 eral systems. 
 
 "The first and most generally used is the closed fire-room 
 type, where all parts of the fire-room and boiler compartment 
 are made as nearly air-tight as practicable, and the air is 
 forced into the space by means of centrifugal blowers, which 
 draw in the air from ventilators or sometimes from the engine 
 room and discharge directly into the fire-room. As there is no 
 other escape except through the grate bar spaces, the fires are 
 forced by means of the greatly increased amount of oxygen 
 available for the purposes of combustion. This system is 
 more comfortable for the firemen, as the cooler air from out- 
 side makes the temperature lower. It gives, however, a some- 
 
6o MC ANDREW'S FLOATING SCHOOL 
 
 what uncomfortable feeling in your ears, as the pressure is, of 
 course, greater than the ordinary pressure of the atmosphere." 
 
 "Why can't you put cotton in your ears?" inquired Nelson. 
 
 "You could if you wanted to, but the pressure would be on 
 the cotton just the same, and there would still be a feeling of 
 pressure on your ear drums. 
 
 "A steam jet in the funnel is another system of forced draft, 
 and probably the simplest that can be devised. The most 
 efficient jet seems to be one that is located right in the center 
 of the stack, and so proportioned as to blow the steam out 
 through a conical opening, causing it to spread out to the sides 
 of the stack and creating a lowering of the pressure in the 
 up-take, which causes a more rapid flow of the air through the 
 fires. Steam jets are not very economical for marine purposes, 
 as they waste too much valuable fresh water. 
 
 "On harbor boats or on vessels running in fresh water, they 
 provide a simple and inexpensive forced draft. All steam 
 locomotives use what practically amounts to steam jet forced 
 draft, as you probably know that the exhaust steam from the 
 two cylinders is turned into the stack, which with the engine 
 at full speed produces a very strong draft. 
 
 "Ash pit draft is another of the four systems used. In this 
 the air is led from blowers through sheet iron ducts, directly 
 to the ash pits, where it is discharged underneath the grate 
 bars. When it becomes necessary to charge the furnace with 
 coal the draft must be shut off, else the flames and gases will 
 be forced out of the furnace doors into the faces of the fire- 
 men. The best type of ash pit forced draft is where the air 
 from the blowers is passed through a heater arranged in the 
 up-takes, whereby some of the heat which would otherwise be 
 lost in the escaping gases is utilized in warming the air which 
 is used for combustion. 
 
 "Induced draft is used on many vessels; this is caused by 
 locating a large blower at the base of the stack, which draws 
 
FORCED DRAFT 6l 
 
 the gases from the up-takes and discharges them higher up 
 in the stack or funnel. This is much less expensive than the 
 closed fire-room system, and in case of any leaks in the 
 breeching or up-takes the air from the outside rushes in, 
 and thus prevents the escape of gases into the fire-room space, 
 as frequently occurs when natural or forced draft of the other 
 types is used, 
 
 'This will close my remarks on the subject of boilers, and 
 as O'Rourke has fallen asleep twice in the last ten minutes. I 
 think you had all better 'turn in/" 
 
CHAPTER IX 
 
 Engines 
 
 On the following evening McAndrew began his lecture by 
 saying : 
 
 "Young men, we are now about to take up a subject which 
 I know will interest you greatly, as you all hope to be engi- 
 neers ; that is, men capable of running and caring for engines. 
 
 "O'Rourke, what, in your opinion, is an engine?" 
 
 "Let me see," replied the spokesman of the class. "An 
 engine is something that makes the wheels go around." 
 
 "You're right," replied McAndrew ; "shorn of all qualifying 
 verbiage that is really what it does, and that is its principal 
 function. But how does it do it? that's the question. You 
 all know that when everything is in readiness the man on 
 watch opens the throttle and the screw begins to revolve. If 
 that was the extent of your knowledge you would be simply 
 engine starters and stoppers, but I trust you will know more 
 about it before you get your licenses. 
 
 "As I told you before, if a cubic inch of water is turned into 
 steam the latter would, under atmospheric pressure, expand 
 into almost a cubic foot of steam. When, however, it is con- 
 fined in a steam-tight vessel such as a boiler, it cannot expand 
 into such a large volume, and consequently the pressure rises. 
 When it reaches, say, a pressure of 180 pounds per square 
 inch, it has a tendency to expand into the volume which it 
 would occupy if all pressure were removed. It is this tendency 
 to expand which makes steam valuable as a source of power, 
 and the greater the pressure the greater the expansion. In 
 
ENGINES 63 
 
 this connection you should remember the fundamental rule 
 that the pressure multiplied by the volume is always equal. 
 Thus if we have one cubic foot of steam at a pressure of 100 
 pounds per square inch, it has the same expansive effect as 
 would 10 cubic feet of steam at a pressure of 10 pounds per 
 square inch. 
 
 "When steam is released from the boiler and enters an en- 
 gine, it tends to expand like a compressed spring if the weight 
 is taken from it. When it reaches the cylinder of an engine 
 through the pipe connecting the boiler to the cylinder it starts 
 to expand, and as the sides of the cylinder and the cylinder 
 head are fixed and rigid, the only way it can increase in vol- 
 ume is to force the movable piston in the cylinder up or down 
 as the case may be. This up and down motion of the piston 
 is transmitted through the piston and connecting rods of the 
 engine to the crankshaft which rotates and turns the propeller. 
 
 "There have been numerous kinds of engines invented to 
 utilize the expansive force of steam, and step by step they have 
 been improved upon, until now practically nine-tenths of all 
 the marine engines in use are of the vertical, inverted, triple 
 and quadruple expansion types and the more recent type 
 known as the turbine. Obsolete types, or those which have 
 outlived their usefulness, are of interest to show what steps 
 have had to be taken to reach the present standards, but for 
 your purposes the modern engines are those to which you 
 should devote most of your attention. 
 
 "Nelson, what is your definition of a triple-expansion 
 engine ?" 
 
 "One that has three cylinders, sir," he promptly replied. 
 
 "That is true in part," said McAndrew, "as the majority 
 of triple-expansion engines do have three cylinders; but I 
 want to disabuse your mind of the idea, which so many young- 
 sters seem to have, that the number of cylinders determines 
 the type of the engine. Some compound engines have three 
 
64 MC ANpREW's FLOATING SCHOOL 
 
 cylinders, some triple-expansion engines have four and even 
 five cylinders, so you see that your definition does not hold in 
 all cases. 
 
 "Engines derive their classification or type from what we 
 may call the different stages in which the expansive effect of 
 the steam is utilized. A simple engine is one in which all of 
 the expansive effect is utilized in one stage ; a compound 
 engine is one in which this is accomplished in two stages or 
 periods ; a triple expansion type is one in which it takes three 
 stages of expansion to get all the work from the steam. Thus 
 if we are using steam at 180 pounds gage pressure in the high- 
 pressure cylinder (or first expansive stage) it partly expands 
 during the first step to a pressure of, say, 60 pounds, when it 
 is exhausted into the second stage, or the intermediate cylin- 
 der, as it is termed; there the expansive force is reduced to, 
 say, 10 pounds gage pressure, when it again passes to another 
 stage, or the low-pressure cylinder, in which it is expanded 
 down to an absolute pressure of perhaps 2 pounds, depending 
 upon the vacuum carried in the condenser. The whole process 
 might be compared to wringing the water out of a tablecloth. 
 
 "Now, O'Rourke, I suppose when you were a boy you have 
 helped your mother with the family wash on Mondays, haven't 
 you ?" 
 
 "Sure thing," he replied, "whenever I couldn't stick my kid 
 brother on the job." 
 
 "Well, you might remember that your mother would take a 
 tablecloth out of the bluing water and give it a twist, thus 
 rinsing out considerable water ; after a while she picked it 
 up, took hold of one end of it while you took the other end, 
 and you both twisted it as hard as you could, with the result 
 that more water came out of it. Finally, she put it in the 
 wringer, for which you probably furnished the motive power, 
 and still more water ran out of it. Well, that's the idea of a 
 triple-expansion engine; it takes three processes to get the 
 
ENGINES 65 
 
 work out of the steam, just as it took three processes for you 
 to get the water out of that tablecloth." 
 
 "Gee !" said O'Rourke, "I must have been a triple-expansion 
 laundryman and didn't know it !" 
 
 "I think from the sound of the hot air which escapes from 
 him he must have been a simple one," volunteered his rival, 
 Schmidt. 
 
 "Having, I hope, fixed in your mind the idea of a triple- 
 expansion engine, we will now investigate some of its parts. 
 The cylinders, naturally, are the most important of these, as 
 in the-m the work of the steam is performed. 
 
 "I suppose you know that the name comes from the geomet- 
 rical figure known as a cylinder, as the inside or working 
 surface of the so-called cylinders is perfectly cylindrical; that 
 is, it is exactly circular in section at any point. The outside 
 of a marine engine cylinder is anything but cylindrical, owing 
 to the valve chests, flanges, etc., necessary to fit it for its work. 
 
 "All steam engine cylinders are made of cast iron, because 
 that is the ideal material for the purpose; no other material 
 would fulfill all the requirements. 
 
 "The thickness of cylinders depends upon several things, 
 the most important of which is the strain which it is required 
 to withstand. However, you will find that they are always 
 made much heavier than actually necessary, as all parts of 
 machinery are, when designed, given what is termed a 'factor 
 of safety.' That is, after you have calculated how thick any 
 part should be from a theoretical standpoint, you make it act- 
 ually three, four or even five times as thick, then you will be 
 deadsure that you are on the safe side. You might think from 
 that statement that designing engineers do not have much 
 nerve, and as a matter of fact many of them are lacking in that 
 essential. Experience has, however, taught them to be on the 
 safe side, for in marine machinery particularly emergencies 
 develop in the most unusual way at times which upset all 
 
66 MC ANDREW'S FLOATING SCHOOL 
 
 theories. After cylinders have been in use for a number of 
 years they may become badly scored or out of round, in either 
 of which cases it is necessary to have them rebored. Conse- 
 quently the designer must keep that contingency in mind when 
 determining the thickness. You can always cut off portions of 
 a casting, but you can rarely add anything to them, hence 
 they should be heavy enough at the start. 
 
 "Attached to and cast with the cylinders are the valve chests 
 which contain the valves for regulating the entrance and exit 
 of the steam to and from the cylinders. They, vary in size and 
 shape in accordance with the type and sizes of valves used. 
 
 "The cylinder heads are, of course, a necessary adjunct to 
 close up the tops of the cylinders. Relief valves are always 
 fitted at the top and bottom of each cylinder to relieve any 
 steam pressure in excess of the safe working pressure, but 
 principally to relieve the cylinders of water pressure, in case, as 
 may happen, water collects in the cylinders, either from being 
 carried over from the boilers with the steam or from being 
 condensed in the cylinders before they are properly warmed 
 up. Water is, as you may have observed, practically non- 
 compressible, so that if any collects either at the top or bottom 
 of the cylinder, and the piston moves rapidly against it, some- 
 thing must give way. The relief valves, if properly adjusted, 
 serve the purpose of allowing the water to escape and of pre- 
 venting an accident to the head or to the cylinder itself. 
 
 "To prevent too great a radiation of heat from the cylinders 
 they are lagged with blocks of a non-conductor, such as mag- 
 nesia or asbestos, i]/ 2 to 2 inches thick, held in place either by 
 wood staving or planished sheet iron. This accomplishes two 
 purposes : one of making the engine more efficient by prevent- 
 ing the loss of heat, and the other of keeping the engine room 
 from becoming too hot for comfort. 
 
 "O'Rourke, do you know what a non-conductor is ?" 
 
 "It must be a conductor that don't belong to the union," 
 replied the Irishman. 
 
ENGINES 67 
 
 "Oh ! I'm not talking about street cars," testily replied 
 McAndrew. "There are certain substances which transmit 
 heat very readily, and they are termed 'conductors' ; others 
 which transmit heat very slowly are known as 'non-con- 
 ductors.' It is often said that man cannot improve upon 
 nature, and this is verified by the fact that hair-felt, made 
 principally of cow hair or horse hair, is about the best non- 
 conductor we can use. Hair-felt will burn or scorch if placed 
 on surfaces which are too hot, such as the cylinders of an 
 engine using high-pressure steam, hence combinations of 
 asbestos and magnesia make the best non-conductors for that 
 purpose. 
 
 "The next parts of a marine engine to be considered are 
 the pistons and piston rods. The pistons are made either of 
 cast iron or cast steel ; sometimes for lightness, as in the case 
 of those used in torpedo boat engines, they are made of 
 wrought steel. If they are made flat and of box section, that 
 is, with double walls, the material used is cast iron. However, 
 the majority of pistons are cast solid of conical section to 
 provide the necessary strength, and in this shape are almost 
 invariably of cast steel. In first-class work they should be 
 machined all over, so as to reduce the clearance spaces as 
 much as possible. It is necessary, 410 matter what the type 
 of piston used, to provide some means of preventing the 
 steam from leaking past the piston. This is accomplished by 
 rings fitted in grooves in the rim of the piston, which either 
 from their natural elasticity or from being forced outward by 
 springs of various forms, keep tight against the wall of the 
 cylinder and prevent the leakage of steam. These rings are 
 always made of cast iron, as no other metal will suffice. Great 
 care is usually taken to. prevent the steel pistons from wear- 
 ing against the sides of the cylinders, as steel on iron is a bad 
 combination where the surfaces are not thoroughly lubricated. 
 
 "The piston rods, which transmit the motion of the pistons 
 
68 MC ANDREW'S FLOATING SCHOOL 
 
 to the crossheads, are simply cylindrical columns, securely 
 fastened to the pistons at the top and the crossheads at the 
 bottom, by means of fitting into tapered holes, whictt take up 
 the thrust in one direction and nuts which prevent movement 
 in the other direction. Piston rods are almost invariably made 
 of wrought steel, and to save weight are sometimes made 
 hollow. Now I think I heard one of you fellows say, some- 
 time ago, that a hollow piston rod is stronger than a solid 
 one, or was it a hollow shaft you were talking about? Any- 
 how, you want to forget that, as I find too many people get 
 that foolishness in their minds. A hollow rod or a hollow 
 shaft is stronger than a solid one of the same weight, that is 
 of the same amount of metal used, but you can see that if only 
 the same amount of metal is used the solid rod or shaft will 
 be of a smaller diameter. So hereafter you can say, for 
 example, that a 6-inch hollow rod with a 3-inch hole through 
 it is not as strong as a 6-inch solid rod, but that it is stronger 
 than a 5^-inch solid rod which contains the same amount of 
 metal. Even then it is only stronger when the rod is being 
 pressed down or in compression, as it is called ; when it is 
 being pulled, or is in tension, it would be of the same strength, 
 whether hollow or solid, as there would be the same sec- 
 tional amount of metal to transmit the pull." 
 
 "Why don't they make piston rods square instead of round?" 
 inquired the studious Nelson. 
 
 "I'm glad you spoke of that," replied the instructor. "So 
 far as actually transmitting the work is concerned I sup- 
 pose a square rod would do as well as a round rod, but the 
 rod must pass through the bottom of the cylinder so as not to 
 allow the steam to escape. It would be very difficult indeed to 
 build a stuffing-box around a square rod and keep it tight, 
 whereas with a round rod it is comparatively simple. Another 
 reason is that it is much cheaper to machine a round rod 
 than it is a square one. In passing it will be well to consider 
 
ENGINES 69 
 
 the manner in which steam is prevented from leaking out of 
 the cylinders around the piston rods and valve stems. In the 
 olden days when the steam pressures and consequent tem- 
 peratures were low, it was quite an easy matter to keep rods 
 tight by a simple stuffing-box with an adjustable gland, packed 
 with hemp or other form of soft packing. Nowadays the 
 steam pressures and temperatures are so high that they would 
 soon burn or blow out hemp packing, and the result is that 
 metallic packing has to be used. This has been a fertile field for 
 the inventor, with the result that almost every day a chief en- 
 gineer, when in port, will be met by a man with a new kind 
 of packing, guaranteed to be better than any other kind ever 
 made and capable of saving at least 10 percent in the coal 
 bills. Metallic packing usually consists of rings of cast iron, 
 white metal or composition, held against the rod by the com- 
 pression of springs of ingenious forms. The best of them is 
 the one that keeps the rod the tightest with the least amount 
 of friction." 
 
 "What kind is that?" said O'Rourke. 
 
 "You can search me," replied McAndrew. "Now, having 
 described the principal features of cylinders, we must, in 
 regular order, find what they stand on, or what it is that 
 supports them, as you all know that the cylinders must be 
 held in place as rigidly as possible. 
 
 "What name is given to these supports, O'Rourke?" 
 
 " 'Colyums,' sir !" replied the one addressed. 
 
 "Oh ! you are learning fast," said the instructor, "nearly 
 all old-timers refer to them as 'col-yums' instead of 'col-umns,' 
 as the word should properly be pronounced. 
 
 "Columns are made of numerous designs of cast iron, 
 cast steel and wrought steel. Some engines are supported on 
 cast iron box-section columns at front and, back, but I think 
 the majority of marine engines have cast iron inverted 
 Y-columns at the back and cylindrical wrought steel columns 
 
7o MC ANDREW'S FLOATING' SCHOOL 
 
 at the front, as shown in Fig. 6, where sections are shown 
 also. In nearly all merchant vessels' engines the condenser 
 is built in the engine frame and forms a part of the support 
 for the cylinders. Short columns, to which the guides are at- 
 tached, are bolted to the top of the condenser." 
 
 "I thought guides were men who show 'rubes' around the 
 
 FIG. 6. INVERTED Y AND CYLINDRICAL COLUMN 
 
 city; how do they get in on this engine game?" inquired the 
 'butter-in' of the class. 
 
 "On a marine engine," replied McAndrew, "the guides show 
 the crosshead slippers how to walk the straight and narrow 
 path ; if they permitted them to roam around very much 
 there would be trouble. In that respect they differ from the 
 average two-legged guide such as you have met on shore. 
 
 "The guides shown in the above sketch attached to the 
 Y-columns are the kind used most extensively for marine 
 
ENGINES 71 
 
 work. When the engine is backing, the pressure on the guides 
 is in the direction opposite from that when it is going ahead, 
 so this pressure is overcome by what are known as 'backing 
 guides,' which are shown in section C-D. The space back of 
 the 'go-ahead' guide is usually fitted for water circulation, 
 whereby the cold sea water flowing through removes the heat 
 caused by the friction on the rubbing surfaces. Marine 
 
 
 n 
 
 1 
 
 1 \ 
 
 
 
 
 
 l ; 
 
 [j 
 
 
 >T < 
 
 
 V 
 
 
 I / 
 
 
 
 FIG. 7. CONNECTING ROD 
 
 engines back so little of the time that it is seldom necessary 
 to fit the 'backing guides' for water circulation. 
 
 "On our way down the engine we next come to the connect- 
 ing rod, by means of which the up-and-down or reciprocating 
 motion is transformed into a circular or rotary motion by 
 means of the crank. Perhaps Schmidt can tell us the German 
 name for connecting rod." 
 
 "Sure !" said Schmidt. "In the old country they call it the 
 'verbindungstikken.' " 
 
 "Gee ! "chimed in O'Rourke, "that's about as long as the rod 
 itself!" 
 
72 MC AN DREW'S FLOATING SCHOOL 
 
 "Yes, the word is rather long, and it means, literally, a 
 binding stiek, because it binds or connects the crosshead to 
 the crankpin. These rods are almost invariably forged of 
 mild open-hearth steel. Fig. 7 illustrates the type in most 
 general use. 
 
 "The upper end, as you will see, is forked to span the 
 crosshead, each side of .the fork being fitted with a bearing 
 and the necessary connections to work on the crosshead pin. 
 Solid brass or bronze is used for the bearing metal, as the 
 pressure is too great to permit of the use of soft, anti-friction 
 metal in the bearings. The lower end of the connecting rod 
 is provided with brasses and a cap or binder, all secured by 
 bolts to the T-shaped end of the connecting rod. These 
 brasses are always fitted with 'Babbitt' or other anti-friction 
 metal to reduce the rubbing friction on the crankpin. The 
 white metal surfaces are scored with oil grooves to allow a 
 proper distribution of the lubricating oil. Bearings, such as 
 crosshead and crankpin brasses, necessarily are subject to 
 wear, and consequently must be provided with means of taking 
 up the lost motion. To that end there are spaces between the 
 top and bottom brasses in which are fitted distance pieces of 
 composition and a varying number of strips of thin sheet brass 
 or tin called 'shims,' which, when removed, take up the lost 
 motion due to the wear on the brasses. Later on I will de- 
 scribe to you the method of adjusting crosshead and con- 
 necting rod brasses, which constitutes one of the most import- 
 ant of the many duties which befall the marine engineer. 
 
 "The crankshaft is the member that actually turns the pro- 
 peller, and hence is the connection between the producer and 
 the consumer of the power, or the middleman, as they would 
 tell you in business circles." 
 
 "He's the guy that causes the high cost of living; but I 
 never heard him called a crank before," suggested O'Rourke. 
 
 "Anyhow, the crankshaft is a very important part of an 
 
ENGINES 
 
 73 
 
 engine," continued McAndrew. "Nearly all crankshafts are 
 forged of mild open-hearth steel, but some still are built-up 
 forgings of wrought iron. In some high-class marine work 
 the crank for each cylinder is forged in one solid piece, such 
 as shown in Fig. 8. 
 
 FIG. 8. SECTION OF FORGED CRANKSHAFT 
 
 FIG 9. SECTION OF BUILT-UP CRANKSHAFT 
 
 "The advantage of a crankshaft of this kind is that the sec- 
 tions are interchangeable, so that, for instance, if the low- 
 pressure crankpin should break the high-pressure crank could 
 be put in its place and the engine run compound that is, if 
 the engine was of the triple-expansion type. The built-up 
 crankshaft is, as its name indicates, composed of several 
 parts, the slabs being shrunk and keyed onto the crank pins 
 and sections of the shaft as shown in Fig. 9." 
 
74 
 
 MC ANDREW S FLOATING SCHOOL 
 
 "Why do some crankshafts have holes in them?" inquired 
 Pierce. 
 
 "That is done in high-class work for two principal reasons. 
 One is that it saves weight and the other is that in making 
 large forgings of this kind most of the imperfections, or 
 'pipes,' as they call them, are liable to be in the central part 
 
 
 FIG. 10. BEDPLATE FOR TRIPLE-EXPANSION ENGINE IN ONE CASTING 
 
 of the forging. Making the shaft hollow either removes the 
 imperfections or exposes them to the view of the inspector. 
 
 "As I told you in the case of the piston rod, a hollow shaft 
 is not stronger than a solid shaft, as many young men im- 
 agine ; it is simply stronger than a solid shaft containing the 
 same amount of metal. To transmit a twisting strain the 
 metal on the outside of the shaft counts much more than 
 metal at the center. For example, take a shaft 10 inches in 
 diameter; the outer portion of the metal only .16 inch in 
 thickness is of as much service in transmitting torsional or 
 twisting strains as the metal 5 inches in diameter at the 
 center of the shaft. Perhaps it will give you a better idea of 
 what I am getting at to state that a shaft 16 inches in diameter, 
 having a lo-inch hole through it, is equal in strength to a solid 
 shaft 15 inches in diameter made of the same kind of metal. 
 
ENGINES -5 
 
 "Further advantages of hollow crank pins are that in case of 
 a pin breaking it could be repaired temporarily by fitting a 
 large bolt through the hole, which would allow the engine to 
 foe run slowly at least; the hole through crank pins is also used 
 to advantage in some engines to permit of the fitting of cen- 
 trifugal oiling devices. 
 
 "The bed-plate is the part of the engine which supports the 
 weight of the entire structure, and also forms the seating for 
 
 FIG^-ll. DETAILS OF BEDPLATE IN FIG. 10. SECTIONS SHOWING MAIN 
 
 PILLOW BLOCK 
 
 the crankshaft or main bearings. They are usually made of 
 cast iron and sometimes of cast steel, and consist of a series 
 of athwartship girders, one under each crankshaft bearing, all 
 being joined by fore-and-aft girders, one on each side. Natur- 
 ally, they are made as heavy and substantial as possible. The 
 ibed-plate is secured to the foundation, an integral part of the 
 ship's structure, by means of holding-down bolts. Fig. 10 
 will show you an ordinary type of bed-plate and Fig. n a 
 main bearing, or 'pillow block,' as it is sometimes called. 
 
 "The main bearing shown in this sketch is such as used for 
 small engines. On larger engines the bottom brass and the 
 cap or binder, as the top bearing is called, are usually cored to 
 
76 MC ANDREW'S FLOATING SCHOOL 
 
 allow for the circulation of sea water in order to prevent the 
 bearing from becoming unduly heated when the engine is run 
 at full speed. All main bearings are lined with Babbitt or 
 other anti-friction metal to reduce the friction." 
 
CHAPTER X 
 Valves and Valve Gear 
 
 "Having gone over the principal parts of the engine, we will 
 now take up some of the miner parts, the principal one of 
 which is the valve gear. 
 
 "It is highly important to allow the steam to enter the 
 cylinder at the right time, and it is equally as important to let 
 it out at the right time. These operations must necessarily be 
 performed automatically. The story is told that in the first 
 engine built by James Watt, which was, of course, a very 
 crude affair, he had not progressed far enough in his design 
 to have the valve operated by the engine itself, and, in con- 
 sequence, a boy was employed to lift the valve and close it at 
 about as near the proper time as his limited training and 
 judgment would allow. Evidently tiring of such monotonous 
 employment, and being of an ingenious turn of mind, he 
 noticed that a certain part of the engine mechanism had about 
 the same motion which he imparted to the valve and at about 
 the same time. Consequently, as the story goes, he tied a 
 stout piece of cord to the valve lever and connected it to the 
 part of the engine which had the coincident motion, where- 
 upon the valve was actuated automatically, and the boy was 
 found by his employer out in the yard playing marbles, civil- 
 ization having not advanced sufficiently far at that remote 
 period to permit of the youngster indulging in the more scien- 
 tific game of shooting craps. 
 
 'That boy unconsciously formed the first valve gear ever 
 put on an engine, but since his time there has been consider- 
 
78 MC ANDREW S FLOATING SCHOOL 
 
 able improvement in the method of actuating valves. Before 
 describing any methods for moving the valve, you had first 
 better be given an idea of the valve itself. There are a number 
 of different kinds of valves used on stationary engines, but 
 for marine engines there is practically but one type used, and 
 that is known as the slide valve. 
 
 "There are two principal types of slide valve : the flat D and 
 the piston valve. The simplest kind of a flat D slide valve is 
 like Fig. 12. 
 
 FIG. 12. PLAIN SLIDE VALVE, MID-POSITION 
 
 'This valve, by sliding back and forth over the valve seat, 
 alternately admits and releases steam to and from the cylin- 
 der which drives the piston up and down. In Fig. 12 
 the valve is shown in what is known as its mid-position. The 
 amount which the valve overlaps the steam port in this posi- 
 tion, A B, is known as the 'lap' of the valve, and you must fix 
 that in your memory, as it is frequently referred to by all 
 marine engineers. There are two kinds of lap, as you will 
 notice that on the inside of the valve it also extends over the 
 port the distance C D. The outside lap, A B, is known as the 
 'steam lap,' and the inside lap, C D, is the 'exhaust lap.' 
 
 "In Fig. 13 the valve is shown at the end of its stroke, 
 and you will notice that the valve has opened one of 
 the steam ports on the outside a distance, A B; this is known 
 as 'lead,' and there are two kinds of lead also; the outside, or 
 
VALVES AND VALVE GEAR 79 
 
 A B, being known as the 'steam lead,' and the inside, or C D, 
 being known as the 'exhaust lead.' " 
 
 "Chief, that sounds like horse race dope, the kind I used to 
 hear down at Brighton Beach," said O'Rourke. "I suppose 
 you will be telling us next that the high-pressure valve is in 
 the^ lead one lap ahead of the low-pressure." 
 
 "No doubt, young man, you know more about horse race 
 dope than you do of anything else ; but this is no place for such 
 silly remarks," tartly rejoined Me Andrew. 
 
 "Why does a valve have this lap ?" inquired Nelson. 
 
 "There is some sense to a question like that," said the in- 
 structor. "Lap is given to a valve so that the steam can be 
 
 FIG. 13. PLAIN SLIDE VALVE. POSITION FOR END OF STROKE 
 
 cut off at a portion of the stroke and be allowed to expand 
 in the cylinder. If the valve was made the same over-all 
 length as the distance between the outer edges of the two 
 steam ports, live steam from the boiler would be allowed to 
 follow the piston nearly the entire stroke, and we would 
 gain nothing from the expansive effect of the steam. 
 
 "As the piston nears the end of its stroke, a certain amount 
 of the exhausting steam in the end of the cylinder towards 
 which the piston is traveling is retained, and as it cannot 
 escape it is compressed and forms a cushion, which overcomes 
 the momentum of the piston, rod, etc. As this is generally in- 
 sufficient to overcome so much momentum, the live steam' for 
 the return stroke is admitted prior to the time when the 
 
8o MC ANDREW'S FI/JATING SCHOOL 
 
 piston starts on its return. The amount the steam valve is 
 open at the very commencement of the return stroke is, as 
 before stated, known as 'lead,' the purpose of which is to aid 
 in quickly overcoming the momentum of the moving parts and 
 to start the piston back quickly on its return. 
 
 "Some old-fashioned simple and compound engines are 
 furnished with a cut-off valve separate, and working upon the 
 back of the regular valve in order to get a sufficient amount 
 of expansion of the steam, but in triple or quadruple-expansion 
 engines we do not need to cut off closely in the high-pressure 
 cylinder, as there are three or four cylinders in which the 
 expansion may take place. A double-ported slide valve is one 
 used when it is desired to get a very large port opening for a 
 comparatively short valve travel; it is practically one valve 
 within another, and there are two steam ports instead of one 
 in the valve seat, the steam for the outside ports entering over 
 the ends of the valve and the steam for the inner ports coming 
 through passageways in the sides of the valve. On nearly all 
 large cylinders it is found necessary to use these double-ported 
 valves, or otherwise the valve travel would be entirely too 
 great. 
 
 "The great disadvantage in using the flat slide valve is the 
 large amount of power consumed in overcoming the friction 
 between the valve and its seat. For instance, a slide valve of 
 ordinary size would be, perhaps, 30 inches long by 42 inches 
 wide, a flat surface of 1,260 square inches. At only 40 pounds 
 pressure per square inch in the steam chest there would be a 
 pressure of over 50,000 pounds pressing the valve against the 
 valve seat- You can readily imagine that the friction caused 
 by moving iron against iron with such a load as that is 
 enormous. Therefore, flat slide valves are not used to any 
 great extent nowadays except in small engines, and then only 
 for the low-pressure cylinder, where the initial pressure of the 
 steam entering the cylinder is usually not over 5 to 10 pounds. 
 
VALVES AND VALVE GEAR 
 
 81 
 
 "Some wise old-timer, to get away from using flat slide 
 valves, conceived the idea of wrapping up his slide valve into 
 
 FIG. 14. PISTON V.ALVE 
 
 the form of a cylinder, and thereby removing all unbalanced 
 pressure from the valve while retaining the advantages of .the 
 slide valve. Its essential features are two pistons or heads 
 
82 MC ANDREW'S FLOATING SCHOOL 
 
 joined by an intermediate distance piece, all being held in 
 place on the valve stem by nuts and washers, as shown 
 in Fig. 14. 
 
 "The steam is admitted and exhausted to and from the 
 cylinder by the edges of the valve in precisely the same manner 
 as the flat slide valve. The only disadvantage is the excessive 
 clearance as compared with the flat valve." 
 
 "What's clearance, Chief?" remarked Nelson. 
 
 "The clearance space in an engine is the volume of the steam 
 ports and passageways between the piston and the bottom and 
 top heads of the cylinder. It would never do to have the 
 moving piston strike the head, either at the bottom or top, for 
 if it did it would knock them off. Consequently there is 
 usually a space of about l /^ inch at the top and ^ inch at the 
 bottom, always more at the bottom to allow for the bearings 
 wearing down. These distances are known as the linear clear- 
 ances, while the entire volume of the space between the piston 
 at the end of its stroke and the cylinder head, plus the volume 
 of the steam passageways, is known as the volumetric clear- 
 ance. Naturally, as the ports have to reach clear around the 
 piston valve, there is more of this volumetric clearance for 
 this type than there is for a flat valve which lays close up 
 to the cylinder. In modern engine designs this volume is 
 considerably decreased by making the ports straight instead of 
 curved, as shown in the sketch. 
 
 "Piston valves can be kept tighter than flat slide valves, for 
 the reason that it is usual to fit the two pistons composing the 
 valve with packing rings similar to those used for the main 
 pistons. 
 
 "We have looked into the principal kinds of valves used on 
 marine engines and know what functions they perform, now 
 we want to know what kind of apparatus it is that moves the 
 valves. There are three principal types of operating gear used 
 on marine engines, known by the names of the inventors, re- 
 spectively, as 'Stephenson,' 'Joy' and 'Marshall.' 
 
VALVES AND VALVE GEAR 83 
 
 "The Stephenson gear is probably used on over 90 percent 
 of the marine engines in use. If ship's engines had to travel 
 in one direction only, the valve mechanism would be com- 
 paratively simple, but engines of this kind, as well as those on 
 locomotives, have to be reversed frequently, so it is neces- 
 sary to have the valve gear designed so that it can go either 
 ahead or back. 
 
 "This condition was quite readily solved by Stephenson, 
 one of the first engineers, when he invented his link gear. In 
 this mechanism the fundamental motion is taken from the 
 
 FIG. 15. PLAIN ECCENTRIC, SKELETON MOTION 
 
 crankshaft by means of eccentrics keyed to the shaft. Per- 
 haps O'Rourke can tell us the difference between an eccentric 
 and a crank." 
 
 "That's easy," replied the ever-ready. "If a rich man does 
 queer things he is an eccentric, but if a poor man does the 
 same stunts everybody calls him a crank." 
 
 "Well, that brings out the idea, anyhow," continued McAn- 
 drew. "There is in reality very little theoretical difference 
 between an engine eccentric and a crank, as an eccentric is 
 practically a self-contained crank. The term 'eccentric' means 
 literally 'having different centers,' whereas 'concentric' means 
 having the same centers. Hence it is that the center of the 
 sheave, forming the eccentric, is set off from the center of 
 the shaft upon which it operates, a distance which is known as 
 the 'eccentricity' or 'throw.' The following will illustrate the 
 idea of the eccentric : 
 
8 4 
 
 MC ANDREW S FLOATING SCHOOL 
 
 "The distance A C, Fig. 15, between the center of the shaft 
 and that of the sheave is the throw, and the up-and-down mo- 
 tion imparted to the valve, or the valve travel, as it is known, 
 is double this throw. Around the eccentric sheave is fitted a 
 band or strap, as it is termed, made in halves and bolted to- 
 gether, which strap is bolted to the heel of the eccentric rod. 
 This rod is forked at its upper end and spans one end of the 
 
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 3 
 
 3 3 
 
 rrn 
 
 
 i 
 
 1 
 
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 1 _! 1 
 
 H 
 
 i , ... 
 
 ~T 
 
 i 
 
 /f^TTvh ' ' ~~ 
 
 1 ^ 
 
 M^. 
 
 f 
 F 
 
 1 O 
 
 IT 
 
 f..:.-))O 1 1 
 
 u HJ 
 
 
 Fin 
 
 FIG. 16. STEPHENSON DOUBLE BAR LINK 
 
 link. There are two eccentrics and all the necessary con- 
 nections for each cylinder, one known as the 'go-ahead' and 
 the other as the 'backing' eccentric. The go-ahead eccentric 
 rod connects with one end of the link and the backing eccen- 
 tric rod with the other end. 
 
 "Almost all links for large engines are of the double-bar 
 type ; that is, they are built up of two parallel steel bars, each 
 forming the arc of a circle, the radius of which is equal to the 
 distance between the center of the eccentric sheave and the 
 center line of the bars. 
 
VALVES AND VALVE GEAR 85 
 
 "You will notice the mechanism in the center of the link. 
 That is known as the link block, and it forms the connection 
 between the link' and the valve stem. In operation the links 
 are thrown from one side to the other, so that the link block 
 is actuated by either the go-ahead eccentric or the backing 
 eccentric, as may be desired, by placing the link block in line 
 with either of these eccentric rods. 
 
 "Eccentric sheaves are always made of cast iron, in two 
 unequal halves, in order to bring the joint between them on 
 the center line of the shaft, so that they can be readily re- 
 moved. 
 
 "The eccentric straps which ride on the sheaves are also 
 made in halves, bolted together, and are usually of cast iron or 
 cast steel, lined with white metal in order to reduce the 
 friction. 
 
 "Eccentric rods and link bars are usually made of wrought 
 steel of the best quality. The link blocks are usually of 
 forged steel, fitted with composition wearing pieces where they 
 rub on the link bars. Sometimes they are cast entirely of 
 bronze. 
 
 "To reverse an engine, that is, to change it from the ahead 
 motion to the backing motion, or vice versa, there is provided 
 a rock shaft, which extends along the engine columns, and to 
 which it is supported in brackets. On this rock shaft there is 
 secured for the valve gear of each cylinder a lever, or re- 
 versing arm, as it is called. This arm connects to the valve 
 gear links by suspension or bridle rods, as they are sometimes 
 called. This rock shaft on small engines is operated by hand 
 through the medium of a long lever, or in some cases by a 
 large hand-wheel and screw. However, this means is not 
 practicable for larger engines, as it would require more power 
 than a man could apply. Hence all large marine engines are 
 fitted with what is known as a reversing engine, which. con- 
 sists of a steam cylinder, the piston rod of which is connected 
 
86 
 
 MC ANDREW S FLOATING SCHOOL 
 
 by means of links to the reverse arm on the rock shaft. 
 Fig. 17 will show you details of an ordinary reversing engine. 
 "The valve of this steam cylinder is controlled by what is 
 termed a 'floating lever,' the initial motion being given it by 
 means of the hand reversing lever located at the working 
 platform. A small slide valve of either the flat slide or the 
 
 FIG. 17. FLOATING LEVER REVERSE GEAR 
 
 piston slide type controls the admission of the steam to the 
 cylinder. Unless the lever at the working platform is handled 
 by an experienced man, the piston is liable to go forward or 
 backward with a rush, causing the gear to slam. To avoid any 
 damage being done it is customary to fit strong spiral springs 
 at each end of the crosshead guide rod to prevent slamming." 
 
CHAPTER XI 
 
 Engine Fittings 
 
 "As we look into the fittings which go on a boiler we should 
 also pay some attention to what are known as engine fittings. 
 
 "The principal of these is the throttle valve, by means of 
 which the engine is started or stopped at will. It is custom- 
 ary to bolt the throttle direct to the high-pressure valve chest, 
 and to operate it by means of a lever and rods from the work- 
 
 FIG. 18. DOUBLE BEAT POPPET VALVE 
 
 ing platform. The most generally used type of throttle valve 
 is known as the double-beat valve, the general principles of 
 which are shown in Fig. 18. 
 
 'This is really two valves in one, the steam entering through 
 two openings in the valve casing. The two disks are worked 
 on one stem, the upper disk being made slightly larger than 
 the lower one, so that the tendency is always to close the valve. 
 However, this difference in the load on the two disks is so 
 slight that it can readily be overcome by means of the throttle- 
 working lever. This lever works on a notched quadrant, and 
 
88 MC ANDREW'S FLOATING SCHOOL 
 
 it is held in position by means of a spring latch. In practical 
 working of a throttle you will find that it only needs to be 
 opened a very slight amount in order to work the engine 'to 
 bells/ as it is termed. 
 
 "Right here it may be well to inform you that a valve does 
 not have to be opened very far to secure a full opening, or to 
 have it 'wide open/ as the term is. A little figuring will illus- 
 trate the idea. For example, if you are using a throttle 10 
 inches in diameter, its total area is 10 by 10 by .7854 = 78.54 
 square inches. That is, to find the area of a circle you multiply 
 the diameter by itself, or square it, as the mathematicians 
 would tell you, and then multiply that product by the constant 
 .7854. To find the circumference of a circle you multiply the 
 diameter by the constant 3.1416. This last constant is known 
 as 'pi'; now don't be alarmed, O'Rourke, for that is not the 
 kind you eat, it is simply the Greek letter that is selected to 
 represent the ratio between the diameter and circumference 
 of a circle. The circumference of a lo-inch circle is 31.416 
 inches. Dividing 78.54, the area in square inches, by the 
 length of the circumference, 31.416 inches, you will find the 
 answer to be 2.5. In other words, a lo-inch throttle valve 
 has to be opened only 2^ inches to be wide open. You should 
 also note that 2^2 is just one-fourth of 10, and bearing in 
 mind that the ratio between the circumference and diameter 
 of all circles is the same, you will see that any valve has to 
 be raised only a distance equal to one-quarter its diameter to 
 be 'wide open.' 
 
 "Most valves are designed to allow a larger opening, but you 
 will see from the illustration that it is not necessary to jam 
 a valve open as far as it will go in order to get the full area 
 through it." 
 
 "Isn't it possible to get a triple-expansion engine stuck on 
 a center?" asked Pierce. 
 
 "Yes, it is not only possible but it occurs quite frequently," 
 
ENGINE FITTINGS 89 
 
 answered McAndrew. "To avoid trouble of this kind all 
 compound and triple-expansion engines are fitted with what 
 afe termed 'pass-over valves.' " 
 
 "That must be a Jew valve !" suggested O'Rourke. 
 
 "This is hardly that kind of a valve," continued the in- 
 structor. "The necessity for such a valve occurs when the 
 high-pressure crank is on the top or bottom center, a con- 
 dition which generally arises at the most inopportune times, 
 such as working the vessel into a dock. However, by quickly 
 opening the pass-over valve, a small stop or slide valve, live 
 steam is admitted into the intermediate valve chest, which 
 starts the intermediate piston in motion and pulls the high- 
 pressure crankpin over the center. The hand-wheel or lever 
 for controlling the pass-over valve is always located at the 
 working platform within convenient reach of the man operat- 
 ing the engine." 
 
 "Why are drain valves necessary?" asked Schmidt. 
 
 "Because steam when entering a cold cylinder or valve chest 
 is condensed into water, which, if not allowed to drain off, 
 would cause a water hammer and might break a cylinder 
 head. Drain valves are located at the bottom of each valve 
 chest and cylinder at the lowest points. Sometimes they are 
 operated by means of an extension rod and a hand-wheel at 
 the side of the cylinder, but more often by means of shafts and 
 levers located close up to the working levers, so that the man 
 operating the engine can open or close the dram from any 
 cylinder without leaving his position. 
 
 "Relief valves are located on each valve chest and at the 
 top and bottom of each cylinder. These are, in reality, small 
 safety valves, similar to those used on boilers, and are for 
 the purpose of automatically relieving any excess pressure, 
 either of steam or water, mostly that caused by water, in the 
 cylinders." 
 
 "What is the use of a turning engine ?" inquired Nelson. 
 
QO MC ANDREW S FLOATING SCHOOL 
 
 "That's easy," volunteered O'Rourke. "It's to keep us 
 horny-handed sons of toil out in the fire-room from breaking 
 our backs by jacking the old engine over every day!" 
 
 "Judging from some firemen I have had with me," replied 
 McAndrew, looking straight at O'Rourke, "working the turn- 
 ing gear is about the only real work you can get out of them 
 while the vessel is in port. 
 
 "Turning-engines are not usually fitted on engines of less 
 than 3,000 horsepower, as it is much simpler to have the 
 ordinary hand gear, which usually consists of a large worm- 
 wheel secured to the crankshaft just aft of the engine bed- 
 plate ; a small, vertical or inclined shaft pivoted at the bottom 
 works the worm, which meshes with the main turning wheel, 
 the shaft being operated by a ratchet lever. If steam power is 
 used it is usual to drive the worm-wheel by means of one or 
 two small cylinders, the whole apparatus being so geared that 
 it takes hundreds of revolutions of the small engine to turn 
 the main engine over once." 
 
 "Why do you have to turn the main engine over when steam 
 is not on it?" asked Pierce. 
 
 "It is quite often necessary to do so when making adjust- 
 ments to the crankpin brasses, in order to get the particular 
 crank on the top center; sometimes it is necessary to jack the 
 main engine over while adjusting the valve gear. All engines 
 in which metallic packing is used for the rods should be 
 jacked at least once each day, in order to prevent rough places 
 being formed on the polished rods from standing too long in 
 contact with the packing at any particular point of the stroke. 
 
 "Leaving the main engine and looking aft, the first thing of 
 importance we see is what is known as the 'thrust bearing,' 
 a most important element in steam machinery, as it is by 
 means of this piece of mechanism that all of the driving power 
 of the propeller is transmitted to the ship itself. 
 
 "As the propeller revolves in the water it has the same ten- 
 
ENGINE FITTINGS QI 
 
 dency to advance that a screw has in a piece of wood, and 
 it is this pushing effect, or thrust, as it is called, which, trans- 
 ' mitted through the agency of the shafting and the thrust bear- 
 ing, drives the ship along. This bearing therefore must be 
 firmly secured to the hull of the ship, and must be so designed 
 as not to become overheated on account of the necessarily 
 large amount of friction on the bearing surfaces. That part 
 of the shafting upon which the thrust bearing is located is 
 known as the 'thrust shaft,' and it is usually made short in 
 length in order to facilitate its removal from the ship when 
 it becomes necessary, as may happen, that it has to be placed 
 in a lathe for the purpose of removing the scores from the 
 bearing surfaces. On this thrust shaft are a number of solid 
 rings or collars, which fit between what are known as 'horse- 
 shoe collars,' and which are supported on rods on each side of 
 the bearing, each being provided with two adjusting nuts on 
 the rods, so that each individual horseshoe may be adjusted 
 to bear a proportionate amount of the thrust of the shaft. The 
 bearing faces of these collars are lined with white metal, so 
 as to reduce the friction to a minimum. The bottom of the 
 bearing usually forms a rectangular tank or trough, which is 
 filled with oil so that the collars on the shaft revolve in it and 
 carry the lubricant to the bearing surfaces. To keep the bear- 
 ing cool it is customary to fit a flat coil of pipe in the bottom 
 of the oil reservoir, and to connect this coil to the water 
 circulating system. The best thrusts also have separate water 
 pipe connections to each horseshoe collar. Too much atten- 
 tion cannot be given to the thrust bearing, for if it is not 
 properly oiled and cooled a great deal of trouble can arise on 
 account of excessive heating. 
 
 "Just aft of the thrust shaft, the main or 'line shafting' ex- 
 tends to what is known as the 'tail shaft,' the last portion of 
 the propeller shafting. This line shafting is known as the 
 intermediate shaft, and is made in one, two or three sections, 
 
92 MC ANDREW'S FLOATING SCHOOL 
 
 according to the length of the vessel. All lengfhs of the shaft- 
 ing proper are made of the best quality of wrought steel, and 
 they should be carefully forged and inspected, as the breaking 
 of any part of this important connection between the main 
 engine and the propeller totally cripples the ship if she is of 
 the single-screw type. It is customary to connect the several 
 
 FIG. 19. DETAIL OF FLANGE COUPLING AND BOLT 
 
 sections of the shafting together by means of what are known 
 as flanged couplings and tapered bolts, as shown in Fig. 19. 
 
 "The bolts are made tapered for convenience in backing 
 them out whenever it becomes necessary to remove a section 
 of the shaft. 
 
 "Each section of the intermediate shafting is usually sup- 
 ported on two bearings, which rest on suitable foundations of 
 plates and angles built up from the frames of the ship. These 
 bearings probably have more names than any other part of 
 the steam machinery. Different people refer to them as 
 'spring bearings/ 'pillow blocks,' 'tunnel bearings/ 'steady 
 bearings' and plain bearings. However, no matter what they 
 are called their function is a very simple one, namely, that of 
 supporting the weight of the shaft and keeping it in aline- 
 ment. With such simple duties to perform, it is customary 
 to fit the bottom with a brass, or to line it with white metal. 
 
ENGINE FITTINGS 93 
 
 The top of the bearing serves no other purpose than to keep 
 the dirt out of it, and to support oil cups or compression cups 
 containing grease for lubricating purposes. 
 
 "Inexperienced oilers, like O'Rourke will probably be, pay a 
 great deal of 'attention to spring bearings, but the old timers 
 give them a familiar slap in passing, as they know that bear- 
 ings of this kind seldom give trouble from overheating. 
 
 "In single-screw vessels the tail shaft, or propeller shaft, 
 passes through what is known as the 'stern tube,' a heavy 
 cylindrical iron or steel casting extending from the after bulk- 
 head of the shaft alley to the eye of the stern post. It is ad- 
 visable, and also customary, to increase the diameter of the 
 tail shaft over that of the intermediate shafting, as where it 
 passes through the stern bearing it is not possible to inspect 
 it often, and being constantly immersed in salt water it may 
 become badly corroded. To provide against this corrosion the 
 tail shaft is usually encased in composition sleeves shrunk on 
 the shaft by heating the casing before it is slipped in place. 
 By carefully soldering the ends and the joints between the 
 sections of the casing, the water is usually kept out, but 
 unless the soldering is well done the water is liable to leak in 
 and cause havoc to the shaft. 
 
 "At the forward and after ends of the stern tube, bearings 
 are formed of composition castings containing dovetailed 
 grooves. In these grooves are strips of lignum-vitae, a tropical 
 wood and about the hardest that grows. The bearing surface 
 should be on the end of the grain, and the strips should be well 
 soaked in oil before being driven into place, as the water 
 which circulates around the shaft is the only lubricant it re- 
 ceives. At the inboard end of the stern tube there is a 
 stuffing-box packed with square hemp or flax packing, a job 
 which can only be attended to while the vessel is in the dry 
 dock. There is usually fitted a small cock and a pipe leading 
 to the water space, by means of which a small stream of water 
 
94 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 is allowed to trickle on the 
 stuffing-box and its gland in 
 order to keep them cool. This 
 also allows a circulation of the 
 water in the stern tube. 
 
 "In sandy or muddy water 
 the lignum-vitae in the bearings 
 is found to cut out quickly, 
 and in some vessels it is cus- 
 tomary to fit a stuffing-box at 
 the after end of the after 
 bearing and to line the stern 
 bearing with white metal. Lub- 
 rication is furnished to such a 
 bearing by means of an oil cup 
 or compression grease cup 
 located above the waterline in 
 an accessible position. 
 
 ''Fig. 20 will show the usual 
 form of stern tube, bearings, 
 etc., used on single-screw ves- 
 sels." 
 
 " C h i e f ," interrupted 
 O'Rourke, "you can't go much 
 further aft without telling us 
 about propellers, can you?" 
 
 "For once, O'Rourke, you 
 are right, as that is certainly 
 the next step. 
 
 "The subject of propellers is 
 one of the most interesting 
 connected with marine engi- 
 neering. Volumes have been 
 written about them, and nearly 
 
ENGINE FITTINGS gcj 
 
 every engineer of any standing in the business has, at one 
 time or another in his career, attempted to invent a new kind 
 that would be far superior to any other propeller ever made. 
 The Patent Office contains about as many propeller designs 
 as there are ships on the seas. About one of these designs in 
 ten thousand is of any practical use, so let me warn you young 
 men never to let your fancies run to the idea that you can 
 invent a propeller. 
 
 'The whole science of propeller designing is based on a 
 process of evolution. Do you know what 'evolution' means, 
 O'Rourke?" 
 
 ''Sure !" said he of Irish extraction. "That means that man 
 is descended from a monkey." 
 
 "You have the idea all right, and the modern propeller has 
 about the same relation to the original propeller as a man 
 bears to his original, in accordance to the theory of a certain 
 philosopher named Darwin. 
 
 "When propellers were first invented, the idea was that 
 they should be as large as it was possible to have them. A 
 story is told of an old-time coasting steamer fitted with an 
 engine of five or six hundred horsepower driving a four- 
 bladed propeller about 15 feet in diameter. She was ambling 
 up the coast one day at a 6-knot clip when the propeller 
 struck a log; whereafter, as the story goes, she imme- 
 diately increased her speed to 7 knots. On examination it was 
 found that one of the blades had been broken off, a fact which 
 immediately started the theory that a three-bladed propeller 
 was the proper thing to use. As a matter of fact, the in- 
 creased speed was undoubtedly due to the reduction in area of 
 an excessively large propeller. 
 
 "The best designed propellers of to-day are those built in 
 accordance with data derived from propellers which have been 
 in use. Step by step they have been improved upon until ft seems 
 that we have to-day reached a point where but little more 
 
96 MC ANDREW'S FLOATING SCHOOL 
 
 improvement can be made. The crude propellers used on the 
 first screw steamers and all propellers used since that time 
 have been useful in developing the modern propeller, as it has 
 been from actual experience, and after very expensive ex- 
 perience, too, that perfection in propeller design has been 
 gradually approached. 
 
 "The results of all these years of experimenting have 
 evolved a standard wheel with uniform pitch and blades 
 elliptical in shape set at right angles to the shaft axis, or 
 slightly raked aft from the perpendicular, according to the 
 individual fancy. The great majority of propellers are now 
 four-bladed, a small portion of them three-bladed, and oc- 
 casionally we see a two-bladed propeller on an auxiliary 
 vessel. 
 
 "Propellers, small in diameter, are almost invariably made 
 solid ; that is, the hub and blades are cast in one piece, such 
 as shown in Fig. 21. 
 
 "Larger propellers are of the 'built-up' type; that is, the 
 blades and hub are cast separately and the blades are flanged 
 and bolted to the hub. The advantages of this type are that 
 in case any of the blades are broken they can be replaced 
 without throwing away the entire wheel, and, further, that 
 by slotting the holes in the blade flanges the pitch can be 
 altered if deemed necessary." 
 
 "What material is best for propellers?" inquired Nelson. 
 
 <r That depends on how much money you have," replied the 
 chief. "In fact it is something like buying underclothes. A 
 poor man buys cotton and it serves the purpose ; a man of 
 moderate means buys woolen that serves the purpose better ; 
 a rich man would buy silk, and that is better than any of the 
 others. 
 
 "With propellers, cast iron serves the purpose and is cheap ; 
 ~ast steel is stronger and costs a little more ; bronze is 
 
ENGINE FITTINGS 
 
 97 
 
98 MC ANDREW'S FLOATING SCHOOL 
 
 stronger, smoother and lasts longer, but costs much more than 
 either of the other materials." 
 
 "I think Schmidt must wear a cast iron undershirt, judging 
 from the rust he has on it," suggested O'Rourke. 
 
 "If shipowners but knew it, polished manganese bronze or 
 other high-class materials would be much cheaper in the end 
 than cast iron or cast steel. A screw driven into wood en- 
 counters considerable friction, and you will be surprised to 
 learn that the screw-propeller driven through the water also 
 encounters a great deal of friction. Experiments have shown 
 that from 10 to 20 percent of the total power of the engine 
 is consumed in overcoming the friction of the screw. Hence 
 it pays to have the blades made as smooth as possible to 
 reduce this frictional loss. Recent experiments of rubbing 
 graphite on the blade surfaces demonstrate that an appreciable 
 amount of friction is reduced by means of that lubricant." 
 
 "What do they mean by the pitch of a propeller?" asked 
 Pierce. 
 
 "McAndrew picked up a bolt that was lying on a bench, and 
 said: "I hold this nut rigid in my hand and turn the bolt 
 head one complete revolution ; you will see that the end of the 
 bolt has advanced about 1/16 inch out of the nut that is 
 what is called the 'pitch' of the thread on the bolt. So with 
 propellers, the pitch is the distance the ship should be driven 
 ahead by one revolution of the screw if it was driven through 
 a solid. But water is not solid by any means, and hence the 
 ship does not advance the distance it should; the difference 
 between what it does advance and what it would advance in a 
 solid is called the 'slip.' This term is always expressed in 
 percentage; for example, if the pitch of the screw is 20 feet, 
 and the ship is driven ahead only 17 feet at one revolution of 
 the engine, the slip is 3 feet, and there would be said to.be a 
 15 percent slip, as 3 is 15 percent of 20." 
 
ENGINE FITTINGS 99 
 
 "How do you tell whether a propeller is right or left- 
 handed?" asked Schmidt. 
 
 "The best way to tell that is to imagine yourself in the 
 bottom of the dry dock looking forward at the propeller. 
 When the screw is driving the ship ahead and it turns in a 
 direction corresponding to the motion of the hands of a watch 
 it is called right-handed. If in the opposite direction then it 
 is left-handed. 
 
 "The driving face of a blade is not, as you might imagine, 
 the forward side, but the after side, as it is that side which 
 acts on the water ; therefore the back of a blade is its for- 
 ward side." 
 
 "That sounds Irish," said Schmidt, glancing at O'Rourke. 
 
 "The area of a propeller, sometimes called the helicoidal 
 area, is the sum of the actual areas of all of its blades. 
 
 "Later on I will try to show you how to calculate the pitch 
 of a propeller by measuring the wheel in position." 
 
CHAPTER XII 
 
 Condensers, Air and Circulating Pumps 
 
 The repairs to the Tuscarora were rapidly nearing com- 
 pletion ; the new boilers were in place, much of the connecting 
 piping had been gotten out and the end of the job was in sight. 
 The students of the "Floating School" had not lost interest in 
 their voluntary work, although their regular duties were now 
 much harder than at the commencement of the repairs. 
 McAndrew had looked for his pupils to slacken in their in- 
 terest in his lectures, but no one had missed a single evening 
 which he had devoted to their instruction. In consequence he 
 had determined to carry the course through for them, and 
 on this particular evening in early March he opened his re- 
 marks by saying : 
 
 "Well, boys, this work I know is rather dry to you, but later 
 on we will get into something more interesting to you. I 
 propose to cover all the principal parts of marine machinery by 
 these lectures, and then to give you some practical questions 
 on the subject and to show you how various problems are 
 worked out. 
 
 "Up to date I have tried to instruct you in a general way 
 as to how steam is generated and how it is utilized to pro- 
 duce power. We now come to the part where, having used 
 the steam, we must get rid of it. This is a step second only 
 in importance to generating the steam. We have seen that by 
 applying heat to water in the boiler steam is formed ; the con- 
 denser serves directly the opposite purpose, for therein the heat 
 is taken out of the steam and it returns to its original state 
 water. Some people look at the condensers as if there were 
 
CONDENSERS, AIR AND CIRCULATING PUMPS 101 
 
 something mystifying about its action, but the process of con- 
 densation is simplicity itself. The very atmosphere we breathe 
 acts as a condenser, for you no doubt have noticed how readily 
 steam escaping from an exhaust pipe is turned into water 
 simply by contact with the air, and especially is this noticeable 
 on a cold day. 
 
 "You might think that in the steam as it leaves the engine 
 there is but little heat left, and as a matter of fact the tem- 
 perature is only about no degrees F. ; but you must remember 
 the first principles and realize that the temperature as shown 
 by the thermometer is only the sensible heat. Do not forget 
 that when the water was transformed into steam it took about 
 934 heat units, known as the latent heat, to bring about this 
 change of state. To turn the steam into water again this latent 
 heat must be taken out in order to accomplish the change, 
 and, approximately speaking, there are 1,000 heat units per 
 pound of steam to be carried off by the cooling water. Herein 
 lies one of the great wastes of any steam plant, and unless the 
 exhaust steam can be utilized for heating the feed water, or 
 for heating buildings in the case of shore plants, there is no 
 way yet devised to prevent it." 
 
 "Chief," interrupted Pierce, "I don't understand how this 
 exhaust steam can have so low a temperature as no degrees 
 F., when you told us that steam did not form until the ther- 
 mometer stood at 212 degrees F." 
 
 "I see," replied the instructor, "that you did not grasp the 
 idea of water boiling at different temperatures according to 
 the pressure it is under. It is true that under atmospheric 
 pressure it does not form steam until 212 degrees, but as the 
 pressure is reduced the boiling point is lowered accordingly. 
 Steam leaving the low-pressure cylinder of an engine is at an 
 absolute pressure of only a pound or two corresponding to a 
 vacuum of 26 or 27 inches, and if you were to boil water in 
 such a vacuum you would find that steam forms at a tern-, 
 
IO2 MC ANDREW'S FLOATING SCHOOL 
 
 perature of approximately no degrees. Hence it is that the 
 exhaust steam has such a low temperature. 
 
 "Fortunately the best medium for condensing steam is cool 
 water, so on shipboard the supply of cooling water is, of 
 course, close at hand. The condenser, as the apparatus for 
 bringing about the transformation from steam to water is 
 termed, is made in two principal types for marine purposes. 
 The jet condenser consists of a large cylindrical casting into 
 which the exhaust steam passes, and where it comes in contact 
 with jets of water which transform or condense the steam 
 to water. As the condensing water is used in such large 
 quantities it must be pumped overboard, together with the 
 water of condensation. For vessels sailing on fresh water such 
 a device is cheap, economical and highly efficient, but for 
 vessels plying in salt water where the condensed exhaust steam 
 must be used over and over again for boiler feed, jet con- 
 densation is absolutely useless. Hence we have what is known 
 as the surface condenser, wherein the steam does not come in 
 direct contact with the circulating or cooling water. 
 
 "Surface condensers are made either cylindrical or rec- 
 tangular in section, according to the space which they are to 
 occupy. When they are built in the engine framing, as most 
 frequently happens in merchant vessels, they usually have a 
 cylindrical top with flat sides and bottom, strongly ribbed 
 to prevent collapse from the external pressure of the atmos- 
 phere. At each end of the condenser there is what is known 
 as a water chest for the entrance and exit of the circulating 
 water. The greater portion of the interior of the condenser is 
 filled with small brass tubes, usually 5/ inch outside diameter, 
 running lengthwise, and fitting into what are known as tube 
 sheets, one at each end of the condenser. These tubes are 
 spaced very closely together, and through them flows the cool 
 sea water. The exhaust steam as it enters the condenser thus 
 comes in direct contact with the outer surface of these small 
 
CONDENSERS, AIR AND CIRCULATING PUMPS 
 
 103 
 
 tubes and is quite readily transformed into water. In order to 
 prevent the steam from striking the tubes in one spot directly 
 opposite the exhaust pipe, it is customary to fit a perforated 
 baffle plate opposite the opening for the exhaust, which baffle 
 plate scatters or deflects the steam along the entire length of 
 the tubes. It is, of course, highly essential that the condenser 
 
 FIG. 22. FERRULES AND TUBE PACKING IN SURFACE CONDENSER 
 
 be kept as tight as possible, for if there are any leaks the salt 
 circulating water will be forced into the body of the con- 
 denser, where it will mix in with the condensed steam and find 
 its way into the boilers. Hence great care must be exercised 
 in packing the ends of the innumerable small tubes. Fig. 22. 
 will show you how these tube ends are made tight. 
 
 "Holes are tapped in the tube sheets into which are screwed 
 small glands known as ferrules, and the packing space is 
 usually filled with corset lacing." 
 
104 MC ANDREW'S FLOATING SCHOOL 
 
 "Gee!" exclaimed O'Rourke, "they ought to carry lots of 
 girls on ships to furnish all that corset lacing." 
 
 "You will notice," continued McAndrew, "that the ends of 
 these glands or ferrules are beaded over slightly. That serves 
 the purpose of preventing the tubes from crawling out of place 
 on account of the contraction and expansion due to the varying 
 temperatures to which these long, slender metal tubes are sub- 
 jected. It also allows them to expand without starting to leak, 
 as would otherwise be the case. 
 
 "If condenser shells are cylindrical in shape it is usual to 
 make them from rolled steel plate, but if they are of rec- 
 tangular section they are almost invariably made of cast iron. 
 The tube sheets are always made of composition. The tubes 
 themselves are made either of brass or Muntz metal, usually 
 coated outside and inside with tin, although many designers 
 do not think that this tinning process is now necessary. At the 
 water ends, particularly, where iron and brass are in such close 
 proximity, it is very important to see that a sufficient amount 
 of zinc plates is suspended in the water to prevent galvanic 
 action. Some careful engineers also have zinc plates fitted in 
 baskets in the fresh-water side of the condenser for the same 
 purpose, although these are not so essential there as in the 
 water chests. 
 
 "This evening as I was coming into the engine room I 
 noticed you boys looking around the main condenser, so I sup- 
 posed you were trying to study its connections." 
 
 "Yes," replied O'Rourke, "Schmidt was trying to find how 
 the air got into the air pump when there is only steam goes 
 into the condenser." 
 
 "I suppose," replied McAndrew, "that the air gets in the 
 air pump just about the same way that water gets in the milk 
 we buy at the corner grocery it's put in. The term 'air pump' 
 is really a misnomer; to be sure, there is a small amount of 
 air gets into the condenser with the steam, but the main func- 
 
CONDENSERS, AIR AND CIRCULATING PUMPS IO5 
 
 tion of an air pump is to pump the condenser water out of the 
 condenser, and incidentally any air and vapor that may be 
 there. 
 
 "Air pumps on board ships are, as a rule, vertical, and of 
 two general types, connected and independent. By 'connected' 
 we mean that they are worked through the medium of beams 
 from one of the crossheads of the main engine, usually the 
 low pressure. The principal advantages of this arrangement 
 are the certainty of action so long as the engine is running 
 and the economy of operation, as the power is, of course, fur- 
 nished by the main engine, which is generally of the most 
 economical multiple-expansion type. Its disadvantage is that 
 there is no vacuum while the main engine is not running. 
 This, however, is not great, as the vacuum is produced almost 
 at the first stroke of the main engine. 
 
 "An 'independent' air pump is one that is driven by its own 
 steam cylinders ; and as a rule .this type is uneconomical, as 
 the economy of operation is only equivalent to that of a slow- 
 running simple engine. There is an advantage, of course, in 
 always having a vacuum in the condenser whether the main 
 engine is running or not. Unless an independent air pump 
 is of very good design and kept in good order, there is always 
 a likelihood of its stopping at the most inopportune times. In 
 this they closely resemble a mule who will work along all right 
 until, perhaps, when crossing a railroad track, he will get 
 balky just as a train is coming along." 
 
 ''Do you start a balky pump the same way that you would 
 start the mule?" inquired Pierce. 
 
 "Very much the same," replied McAndrew. "I once had an 
 Irish oiler with me who would occasionally get mad when the 
 air pump stopped, and would strike it on the valve chest with 
 a top-maul. Very frequently the pump would start off im- 
 mediately on being -given that treatment, probably because the 
 jar would start the controlling valve which had stuck. How- 
 
io6 MC ANDREW'S FLOATING SCHOOL 
 
 ever, I do not recommend such strenuous treatment of balky 
 pumps, and you had better not let me catch any of you striking 
 pump valves that way on board this ship. 
 
 "The air pump itself is usually of the same design, whether 
 operated independently or attached to the main engine. Fig. 
 23 will show you the type usually adopted for marine work. 
 
 "Air pumps are always attached to the very lowest part of 
 the condenser, so that the water of condensation will flow to 
 the pump by gravity. In the sketch you will note that the 
 pump is not unlike any ordinary style of pump for pumping 
 liquids. The valves form the main distinguishing feature. 
 There are, as you will see, three sets of these valves ; the ones 
 at the bottom being termed 'foot valves/ those in the piston are 
 known as 'bucket valves/ and the set of valves at the top are 
 'discharge valves.' 
 
 "The method of operation is that as the bucket or piston 
 starts on its upward stroke a vacuum is produced in the 
 pump barrel, which, when it overcomes the vacuum in the con- 
 denser, causes the water, air and vapor to rush through the 
 foot valves into the body of the pump. On the down stroke 
 the contents of the pump are in turn discharged through the 
 bucket valves, and on the following up-stroke are forced 
 through the discharge valves at the top, whence they go to the 
 hot well or feed tank. You will notice that the top plate on the 
 pump which contains the discharge valves is not bolted to the 
 pump in this sketch, but is held down by a large spiral spring. 
 This is what is known as a floating top, and it is thus ar- 
 ranged so as to allow the ready escape of a large volume or 
 gulp of water which is liable to pass through the pump at any 
 time. Quite often pumps which have not been provided with 
 bucket on a large mass of water which could not escape quickly 
 a floating top have had the top broken by the impact of the 
 enough through the small valves. Most large air pumps are 
 
CONDENSERS, AIR AND CIRCULATING PUMPS 
 
 FIG. 23. VERTICAL ATTACHED AIR PUMP 
 
IO8 MC ANDREW'S FLOATING SCHOOL 
 
 made of cast iron, fitted with a thin composition liner. The 
 bucket should be of composition, and the top and bottom valve 
 plates should also be made of the same material. 
 
 "The air pump valves nowadays are usually made of several 
 light bronze disks of decreasing diameters, the largest diameter 
 being at the bottom. These are held down by light bronze 
 wire spiral springs. Some engineers, however, still prefer 
 vulcanized rubber valves. 
 
 "You will notice that the bucket shown in this sketch has a 
 number of grooves turned in its rim; these are supposed to 
 trap small quantities of water and thus prevent leakage from 
 one side to the other. Ordinarily buckets of this kind are fitted 
 with bull rings and packed with square hemp packing, as that 
 is much more reliable than the so-called water packing. 
 
 'Tumps above 18 or 20 inches in diameter are usually fitted 
 with a manhole in the side of the barrel, so as to provide 
 ready access to the bucket and foot valves without removing 
 the top and the bucket as well whenever it is necessary to ex- 
 amine the lower sets of valves. 
 
 "What pump on board of a ship do you think has the easiest 
 job?" inquired McAndrew, trying to test the knowledge of his 
 pupils. 
 
 "I know," quickly said O'Rourke, "it's the pump in the fire- 
 men's washroom when Schmidt is taking a bath he's afraid 
 of water." 
 
 "I haven't heard of any pump handles being broken when 
 you were taking a bath, either," retorted Schmidt. 
 
 "Well, you will have to decide the bathing proposition your- 
 selves," remarked McAndrew. "But what I wanted to call to 
 your attention is the fact that the circulating pump, a very 
 important adjunct of marine machinery, has comparatively 
 little hard work to do. In condensing the exhaust steam a 
 very large quantity of circulating water is used, as for every 
 pound of steam condensed there is required under ordinary 
 
CONDENSERS, AIR AND CIRCULATING PUMPS lOp 
 
 conditions the cooling effect of about 30 pounds of sea water. 
 Thus for a 4,ooo-horsepower engine, using about 16 pounds of 
 steam per horsepower each hour, there would be required 
 about 3,800 gallons of circulating water per minute. This 
 water has, however, only to be pumped with sufficient force 
 to overcome the friction through the tubes and the small head 
 due to forcing it overboard a few feet above the pump. The 
 requisite force is so small that on fast torpedo boats there 
 is a scoop arrangement at the in-take which, when the vessel 
 is going at full speed, is sufficient to drive the circulating water 
 through the condenser without the help of the pump. 
 
 "The pump almost universally used for circulating purposes 
 is of what is known as the centrifugal type with the accent 
 on 'trif and not on the 'fug,' as I have heard some of you boys 
 pronounce it. By the way, does any of you know the meaning 
 of 'centrifugal?' " 
 
 Not even O'Rourke ventured a reply, so McAndrew in- 
 formed his hearers that " 'centrifugal' means 'flying from the 
 center,' the opposite effect, or 'flying towards the center,' being 
 expressed by the word 'centripetal.' A pump of the centrifugal 
 type is therefore one in which the water entering at the 
 center is driven outward by a revolving series of blades called 
 the 'runner,' and is discharged through an opening in the 
 casing which is connected by a pipe to the condenser. This is 
 an ideal type of pump for circulating the water through the 
 condenser, inasmuch as a large quantity of water can readily 
 be handled at a small expenditure of power. Pumps of this 
 description are ordinarily operated by a single-cylinder engine 
 of the usual type. An extension of the crankshaft of the 
 engine forms the shafting for the pump runner, and inside the 
 pump casing this shafting is usually encased in composition. 
 The runner is generally cast of composition, but with the ex- 
 ception of small pumps the pump casing is made of cast iron, 
 in halves, flanged and bolted together. Pumps of this de- 
 
IIO MC ANDREW'S FLOATING SCHOOL 
 
 scription need but little attention, as there are no valves to 
 get out of order as is the case with the ordinary types of re- 
 ciprocating pumps. Being of such an advantageous type, 
 centrifugal feed pumps are now used on shipboard to a limited 
 extent, little difficulty being encountered in forcing water into 
 a boiler against a pressure of as high as 200 pounds. Feed 
 pumps of this description are driven by small steam turbines." 
 
 ''Suppose the circulating pump should break down, how 
 would you keep running?" inquired the observing Nelson. 
 
 "There is very little possibility of such an accident oc- 
 curring, but it is a wise thing to prepare for even so remote 
 an emergency," answered McAndrew. "I have seen some 
 ships fitted with a special discharge pipe from the fire pump 
 or the auxiliary feed pump to the water end of the condenser. 
 I know of one ship in particular where the casing of the cir- 
 culating pump collapsed on account of excessive corrosion on 
 the inside. The chief engineer was a resourceful fellow, and 
 fitted two hose connections to the small handhole plates on the 
 water chest of the condenser; then by connecting up two 
 lengths of fire hose to the fire main and running the auxiliary 
 feed pump, he managed to keep sufficient vacuum in the con- 
 denser to run the engine along at half speed, and the ship 
 got safely into port." 
 
 "Suppose your air pump busted, what would you do?" asked 
 O'Rourke, not to be outdone in asking questions by his mates. 
 
 "Even the permanent disabling of the air pump need not 
 put the engine out of business," replied the Chief. "If worse 
 came to worse, you could take down the main exhaust pipe, 
 rig up a temporary pipe out of heavy canvas, and exhaust to 
 the atmosphere tugboat fashion. Many steamers have a 
 suction pipe connecting the channel-way under the air pump 
 direct to the main feed pump. By this method the condenser 
 can be kept clear of water, and a fair amount of vacuum 
 maintained. 
 
CONDENSERS, AIR AND CIRCULATING PUMPS III 
 
 "You will find, as you live longer, that the application of 
 good common sense and some ingenuity will help you out of 
 many difficulties which at first seem insurmountable. These 
 attributes are possessed by almost every marine engineer, as 
 the very nature of his business requires a liberal use of both 
 of them. Those are the qualities which make marine engineers 
 the best operating engineers for any type of machinery." 
 
CHAPTER XIII 
 
 Feed Water Filters, Pumps and Injectors 
 
 "Having followed the steam along until it is condensed into 
 water, our next step will be to get it back into the boiler, 
 ready for its transformation into steam again ; incidentally we 
 will stop at one or two of the way-stations, as they say on 
 railroads. 
 
 "After the water leaves the hot well or the air pump, it is 
 usual to subject it to a filtering process in order to remove 
 the grease and other impurities which become mixed with the 
 steam as it passes through the engine. Impure water is just 
 as bad for boilers as it is for human beings: while an occa- 
 sional dose of oil is said to be good for the human system, 
 it is never good for a boiler's 'system/ hence every effort is 
 exerted to keep it out of the feed water. Most^ ships are fitted 
 with what is known as a filter tank, which serves the double 
 purpose of a reservoir for the feed water and a receptacle for 
 filtering materials. 
 
 "The filter tank is customarily fitted with a number of 
 compartments through which the feed water is drawn by the 
 action of the feed pump usually going up in one compart- 
 ment and down in the adjoining space. By this means for a 
 distance of from four to ten feet, according to the size of 
 the tank, it flows through the filtering material, and the oil 
 is supposed to be caught thereby. The material most com- 
 monly used is 'excelsior' (small wooden strings), because of 
 its fairly good qualities for absorbing or entrapping the grease 
 globules as well as its very cheap cost. Ordinary hay is some- 
 
FEED WATER FILTERS, FUMPS AND INJECTORS 113 
 
 times used, but it is not as efficient as the excelsior. Sponges 
 are used to some extent, but they are so expensive that they 
 cannot be thrown away after becoming oil-soaked, and clean- 
 ing them to be used again is not a job relished by the oilers and 
 firemen. A spongy vegetable substance known as 'loofa' is 
 occasionally used, but that too is expensive and has to be 
 washed out and replaced in the compartments. There are 
 several patented filters on the market which utilize various 
 woven filtering materials, such as gunny sacks, etc., but they 
 are all for the accomplishment of one object the removal of 
 grease and oil, the only real, thorough cure for which is to 
 refrain from its use entirely." 
 
 "That," interrupted O'Rourke, "is like curing a mad dog 
 by cutting off his tail close up behind his ears." 
 
 "You have the idea all right, but you will find that both 
 these remedies are difficult of accomplishment," answered the 
 instructor. 
 
 "Now as to the feed tank's use as a reservoir it should 
 have an ample capacity for at least five minutes' supply of 
 feed water for the boilers when the engine is running at full 
 speed, in order to allow for the fluctuations between supply 
 and demand in all steam plants. When feed pumps were 
 located in the fire rooms, water tenders would have to run 
 back and forth to see that the water in the tank was not so 
 low that the feed pump was pumping air into the boilers, or 
 else not so high as to be overflowing into the bilges. The 
 proper system is to have the feed pumps located in the 
 engine room as near as practicable to the feed tank, then by 
 means of a float, rising and falling with the level of the 
 water, and connected by means of rods and bell cranks to a 
 micrometer valve in the main feed pump steam line, the 
 system is so regulated that the water level in the tank can be 
 automatically adjusted. 
 
 "We are now up to the subject of boiler feeding, and in this 
 
IJ 4 MC ANDREW'S FLOATING SCHOOL 
 
 connection I will ask you: How does your supper to-night 
 compare in importance with feeding the boilers?" 
 
 "We get our feed and some money besides, while as far as 
 I can see all a boiler gets is its feed," said Pierce. 
 
 "No, that isn't it," broke in O'Rourke, "a boiler lives on 
 liquid food and has to be fed all the time it is working, while 
 we have to work all day and only get fed once "in a while 
 and it's pretty bum stuff at that. Mr. Boiler, though, has to 
 have his feed of the purest brand." 
 
 "That's true," replied McAndrew, "but you must remember 
 that the boiler's stomach is only of steel, while from what I 
 hear, you have a copper-lined stomach. 
 
 "However, I am glad that you appreciate the fact that a 
 boiler has to be fed continually while it is working, as that 
 is the most important thing an engineer has to contend with. 
 If anything goes wrong with the main feed pump there is the 
 dickens to pay, as the boiler's appetite for water allows of no 
 delay. 
 
 "On most ships there are at least three means of forcing in 
 the feed water the main feed pump, the auxiliary feed pump 
 and the injector. It would be a rare series of accidents, in- 
 deed, when at least one of these contrivances would not be 
 available for feeding purposes. 
 
 "The most important is, of course, the main feed pump, as 
 that has to do the brunt of the work. It is customary to 
 make this pump of the duplex type that is, having two steam 
 cylinders and two water cylinders, so arranged that the valve 
 gear of each steam cylinder is worked from the crosshead of 
 the other pump. Some engineers prefer the simplex type, and, 
 in my opinion, there is really very little choice, except that 
 the simplex type costs less and occupies comparatively less 
 space. The choice between horizontal and vertical pumps is 
 also largely a matter of opinion, as there are engineers of 
 equal standing who have preference for both types. The best 
 
FEED WATER FILTERS, PUMPS AND INJECTORS 115 
 
 feed pump is the one that gives the least trouble and is the 
 most reliable, no matter whether it is simplex, duplex, hori- 
 zontal or vertical." 
 
 "Which one is it?" inquired Schmidt. 
 
 "That's something you will have to learn for yourself, from 
 your own practical experience," answered McAndrew. "I 
 have heard good engineers argue themselves black in the face 
 as to the relative merits of different types of pumps, and at the 
 end neither convinced the other that he was right. 
 
 "Everybody will, however, agree that a main feed pump 
 should be made as simple and strong as possible; that its 
 water cylinders should be made of solid composition if you 
 can afford it; that its steam valve gear can be readily adjusted, 
 and that it keeps running constantly without much watching." 
 
 "How is it," inquired Nelson, "that a pump using steam of 
 boiler pressure can force water into the boiler against the 
 same pressure?" 
 
 "That is very simple," replied McAndrew, "as a boiler feed 
 pump is somewhat on the principle of a lever that is, the 
 steam cylinders are always larger than the water cylinders. 
 For example, a common proportion for an ordinary feed pump 
 is to have steam pistons 8 inches in diameter driving water 
 pistons or plungers 5 inches in diameter. Nelson, what would 
 be the leverage in a pump proportioned like that?" 
 
 "Why, let me see," replied Nelson. "Oh! Yes, it would 
 be i 3/5 times as much pressure on the steam piston as it is 
 against the water piston." 
 
 "Oh, no!" smilingly said the instructor, "you are wrong 
 we are not dealing with straight lines in this case; if it were 
 a bar lever we were using to force the water into the boiler 
 your answer would be correct, but cylinders have circular pis- 
 tons, so the proportion between them varies with the squares 
 of the diameters." 
 
 "What's that mean, sir?" said Nelson. 
 
n6 MC ANDREW'S FLOATING SCHOOL 
 
 "By the square of any number is meant the product ob- 
 tained by multiplying the number by itself. Thus the square 
 of 5 is 25 and the square of 8 is 8 times 8, or 64; hence the 
 leverage we gain in this particular pump is equal to 64 divided 
 by 25, or 2.56. In other words, there is a load on the steam 
 piston of 2.56 times that necessary for the water piston to 
 exert a force equal to the boiler pressure. This proportion 
 is found to be ample to insure the water being forced into the 
 boiler against the boiler pressure, friction in the feed pipes, 
 check valve, etc. Always remember the rule I have given you 
 about comparing things having circular sections and you 
 won't fall into the error I once saw a man make of fitting two 
 2-inch drains to carry off the water put into a tank by one 
 4-inch supply pipe. Tell me quickly, O'Rourke, how many 
 2-inch drains should he have fitted?" 
 
 "Four, of course," replied the Hibernian. 
 
 "Fine work !" said McAndrew. 
 
 "A good guess," sneered Schmidt. 
 
 "There is usually only one suction pipe and one discharge 
 pipe to the main feed pump, so that it will draw water from 
 the feed tank and discharge into the main feed line only. 
 There can then be no complication and no danger from open- 
 ing the wrong valves when the pump is first started up. A 
 properly proportioned pump should work easily and quietly. 
 
 "The auxiliary feed pump is, as you probably know, used in 
 case the main feed pump breaks down. Many people call this 
 the 'donkey pump,' just for what reason I do not know." 
 
 "I know why that old pump on this ship is called a 'donkey' 
 it's because it bucks and kicks so much," suggested 
 O'Rourke. 
 
 "It must do that when you are running it, then," retorted 
 McAndrew. "I never saw it act that way. It's all in knowing 
 how to run a pump you probably tried to start it without 
 
FEED WATER FILTERS, PUMPS AND INJECTORS 1 17 
 
 opening any of the discharge valves. I think the 'donkey' 
 must have been on the other end. 
 
 "The 'donkey pump' is, of course, used for many other pur- 
 poses than as a boiler feeder. It generally has four or five 
 suctions and as many discharges. It can be used for pumping 
 out the bilges, pumping out the boilers, for fire purposes and 
 for washing down decks. When you use this pump you must 
 be very careful to see that you open the right valves. I re- 
 member catching one oiler who was on this ship pumping bilge 
 water into one of the boilers simply because he had opened 
 the wrong suction valve. I fired him at once, as there is no 
 place on this or any other steamship for such careless people. 
 
 ''The auxiliary or 'donkey' pump is frequently a duplicate 
 in construction of the main feed pump, but if possible the 
 water end should be of composition on account of handling 
 salt water. On all well-designed feed pumps there is an air 
 chamber, both on the suction and discharge sides. These an- 
 swer the purpose of a cushion for taking up the shock. Water 
 is practically non-compressible, so that a sudden stroke of 
 the pump acts like a hammer on the whole pipe system unless 
 there is an air chamber wherein the air is compressed like a 
 spring. No work is lost, but the shock of impact is prevented. 
 
 "There is another method of feeding water into a steam 
 boiler besides the main and auxiliary feed pumps, and it is of 
 such importance that every ship should be fitted with at least 
 one. This is known as the 'injector' an apparatus which 
 occupies very little space but is highly efficient and often very 
 useful. Fig. 24 is a sketch of an ordinary type. 
 
 "In the figure shown, the steam is admitted through the pipe 
 B, the entrance to the body of the injector being controlled 
 by the valve which is operated by the handle K. When this 
 valve is opened, the steam rushes through the contracting noz- 
 zle 5. 'The air in the space around the two openings shown 
 is mixed with the steam and forms a partial vacuum sufficient 
 
Ho MC ANDREWS FLOATING SCHOOL 
 
 to draw in the water through the pipe B. This water com- 
 bines with the steam and passes into the combining and de- 
 livery tube C D. The steam is condensed in this tube by con- 
 tact with the water, and the jet thus formed is given a very 
 high velocity, ample to lift the check valve and force it into 
 the boiler. It is really the energy of the inrushing steam 
 which gives the water sufficient momentum to carry it into 
 
 FIG. 24. INJECTOR. 
 
 the boiler. The great advantage of such a device is that it 
 acts as a feed water heater, the water going into the boiler 
 being heated by the steam which gave it the momentum. 
 
 "For some reason or another, people who locate injectors 
 never seem to get them piped up right. They should be 
 arranged so that the lift of the water will be very small not 
 over 4 or 5 feet at the greatest and the discharge pipe to the 
 boiler should be as direct as possible so as to avoid any sharp 
 bends. You have all heard the expression that 'four round 
 turns are equal to a blank flange.' That is not exactly so, 
 but it is nevertheless true that every round turn or right- 
 angled bend in a pipe greatly increases the friction of the 
 water passing through it. 
 
FEED WATER FILTERS, PUMPS AND INJECTORS I IQ 
 
 "In recent years engineers generally recognize the great ad- 
 vantage of a feed water heater, so that no new vessel is turned 
 out without one of these aids to economy. Ten or fifteen 
 years ago it was not generally the practice to fit a device for 
 warming the feed water, but now one of the greatest prob- 
 lems which confront all marine engineers is to get the great- 
 est amount of work out of the least amount of coal. No sin- 
 gle apparatus connected with marine machinery has done more 
 to produce economy of fuel consumption than the feed water 
 heater, a device primarily to utilize heat which has heretofore 
 been wasted through the discharge water from the condenser. 
 Many devices have been invented to heat the feed water by 
 means of the waste gases from the furnaces, but the liability 
 of accidents to the piping thus employed has practically put 
 them out of use. Hence, nowadays, it is almost the invariable 
 practice on steam vessels to have the feed water heated by 
 means of a portion of the exhaust steam from the auxiliaries, 
 such as the dynamos, feed pumps, air pump (when indepen- 
 dent), etc. The best form of feed water heater of this class 
 is where the steam does not come in contact with the feed 
 water. In other words, the modern feed water heater is prac- 
 tically a small surface condenser where the feed water is the 
 circulating medium. These are of various types, some having 
 straight tubes with tube sheets like an ordinary condenser, 
 and others having spiral coils connected to manifolds at the 
 ends. Heat from the exhaust steam is thus transmitted to the 
 feed water, so that it is possible to have the feed water enter 
 the boilers at as high a temperature as 240 or 250 degrees 
 Fahrenheit." 
 
 "I thought water boiled at 212 degrees," suggested one of 
 the class. 
 
 "So it does," said McAndrew, "under atmospheric pressure 
 only, but I have previously pointed out to you that the boiling 
 point of water varies with the pressure, and in this case the 
 
I2O MC ANDREW S FLOATING SCHOOL 
 
 pressure of the feed water is higher even than that of the 
 steam in the boiler." 
 
 "Where does all the saving come in?" inquired Nelson. 
 
 "I'll show you," said the instructor, "as it is quite simple. 
 We will suppose that we are using steam at a boiler pressure 
 of 180 pounds per square inch, and that the feed water we 
 have been using is only 100 degrees, rather cold, but still it 
 is such as is sometimes used when great care is not exer- 
 cised by regulating the circulating pump. Now suppose we 
 have yielded to common sense and fitted the vessel with a feed 
 water heater of the exhaust steam variety, and we find by the 
 thermometer in the feed pipe that the water is entering the 
 boiler at an actual temperature of 230 degrees Fahrenheit. We 
 have thus caused a gain of 130 degrees Fahrenheit. From the 
 'Steam Tables' we find that steam at 180 pounds pressure con- 
 tains 1,198 B. t. u. By a simple calculation we then find how 
 much is saved, thus: 
 
 Total heat in I pound of steam 1,198 
 
 Heat in feed water as used originally (100 32) ... 68 
 
 Heat required to form I pound of steam under old 
 
 conditions . . . . 1,130 
 
 Under the new conditions we have saved 230 100=130 
 B. t. u.'s, and we find that we now only have to use 1,130 130 
 or 1,000 B. t. u.'s for a pound of steam. To find the ratio of 
 saving we divide 130 by 1,130 and it gives 11.5 percent. Thus, 
 if the ship has been using 100 tons of coal for a certain run 
 between ports, it will be found after the feed water heater is 
 fitted that 88.5 tons will do the same work. At $3 (125. 6d.) 
 per ton there will be a saving each trip amounting to $34.50 
 (7 33. 9d.). For 100 trips a year the saving in coal would 
 be $3,450 (707), or more than enough to pay for the new 
 heater the first year it is used. 
 
FEED WATER FILTERS, PUMPS AND INJECTORS 121 
 
 "The saving in fuel is not the only benefit to be derived, as 
 the use of hot feed water undoubtedly prolongs the life of 
 the boiler and prevents many leaks in the seams which result 
 from the use of cold feed water. We might compare the bad 
 effects of the use of cold feed water in boilers to the bad 
 effect on a man's health of drinking too much ice water." 
 
 "Would it make his seams leak?" asked O'Rourke. 
 
 "No. But it often makes his stomach ache, and he will not 
 last as long as the man who slakes his thirst with water only 
 moderately cold. 
 
 "We have now followed the feed water through its various 
 manipulations, and it is prepared to enter the boiler, except 
 for one important essential, and that is taking the air out 
 of it. Many of the ills which befall the interior surfaces of 
 boilers are due to the air which enters with the feed water. 
 There is not in general use any simple device to accomplish 
 this, however, as designing engineers, as a rule, do not pay 
 much attention to this important matter. If a pet-cock is 
 fitted at some bend in the pipe, or if some obstruction is fitted 
 in the pipe, considerable of this air can be blown off, and 
 there are also certain automatic devices which can be used 
 for blowing out the entrapped air. In watertube boilers where 
 the feed water enters above the surface of the boiler water 
 in the steam drum, the air is released to a considerable extent 
 by having the feed water discharge against a small hood over 
 the feed pipe nozzle, so that it enters the boiler in a spray, 
 the air becoming separated and being carried off with the 
 steam. There can be little corrosion in boilers without the 
 oxygen in the air, so that the exclusion of air from the water 
 tends greatly to reduce the pitting and corrosion. 
 
 'The feed pipes leading from the feed water heater to the 
 boilers are usually made of seamless drawn brass or copper, 
 and should run as nearly straight as possible to avoid friction. 
 These pipes, as far as possible, should be run where they are 
 
122 MC ANDREW S FLOATING SCHOOL 
 
 easily accessible in order to detect any leaks, and by all odds 
 the joints should be located where they will be easily accessi- 
 ble for putting in new gaskets, as a leaky joint in a feed pipe 
 is intolerable." 
 
 "What's that?" said O'Rourke. 
 
 "That means something that we cannot stand for, very much 
 like some of your questions." 
 
CHAPTER XIV 
 
 Evaporators and Distillers 
 
 "Which one of you knows the difference between an evapo- 
 rator and a distiller?" said McAndrew, at the commencement 
 of the evening's lecture. Before any of the rest of the class 
 could reply, the ever-ready O'Rourke blurted out, "One of 'em 
 makes dried apples and the other makes booze." 
 
 "You are always talking about something that is most fa- 
 miliar to you, O'Rourke," sarcastically replied the instructor; 
 "while it is true that 'booze' is distilled, we are dealing with 
 water exclusively just now. 
 
 "You may remember that when we had the subject of boilers 
 under consideration, I told you that nowadays only fresh 
 water is used in the boilers. The steam from the engine is 
 condensed over and over again and pumped back into the 
 boilers; but in spite of all the precautions the engineer can 
 take, there is more or less of the water lost on account of 
 leakages around the boilers, at the pipe joints, and around the 
 stuffing-boxes of the main engines and the auxiliaries. Just 
 how much this leakage amounts to, it is hard to estimate, but 
 a goodly supply of fresh water should be carried in the ship's 
 tanks to make up the deficiency of feed. When that is used 
 up, as it generally is after five or six days' steaming on most 
 vessels, then we have to have other means for furnishing the 
 fresh water. Of course, there is always as much salt water 
 to be had as you may want, but the problem is to extract the 
 solid matter from the sea water so that it will not be de- 
 posited on the heating surfaces of the boilers. For this pur- 
 
124 MC ANDREWS FLOATING SCHOOL 
 
 pose the evaporator is used, and you may as well understand 
 that an evaporator is simply a boiler which uses steam to gen- 
 erate steam from sea water. The donkey boiler or one of 
 the main boilers could be used for evaporating purposes but 
 for the fact that the scale would be deposited on their heat- 
 ing surfaces, which are difficult to clean. Hence the most suc- 
 cessful evaporator is the one that is easiest to clean. By using 
 steam from the main boilers to generate steam in the evapo- 
 rator, no fresh water is wasted, as the steam from the inside 
 of the coils is condensed and passed back into the feed tank 
 or condenser. 
 
 "The coils or tubes of an evaporator are usually arranged 
 so that they can be pulled out or gotten at quite readily for 
 cleaning purposes, for after only a day's use they are usually 
 quite heavily incrusted with scale. Scaling evaporator coils 
 at sea is a delightful job, and I am sure that you, O'Rourke, 
 will be tickled to death to do your share of it." 
 
 "Huh !" said that worthy, "I have already done one trick at 
 that business the last ship I was on. I worked so hard at it 
 that I punched a hole through one of the coils, and the first 
 assistant told me I was too strong for such scientific work." 
 
 "The chances are you did it on purpose to get out of work," 
 said McAndrew, "but that shows you that care must be taken 
 in scaling evaporator coils, as they are usually made of brass 
 or copper, and, naturally, are as thin as they can well be made 
 in order to better transmit the heat. The shell of the evapo- 
 rator is made of steel, about the same as you would build a 
 small boiler, only it is a good idea to add at least one-eighth 
 of an inch to the thickness of the plate in order to allow for 
 the excessive corrosion which always takes place around the 
 water-line. 
 
 "There is quite a knack in running an evaporator, as you 
 'will find from experience. The principal thing to guard against 
 is excessive foaming. If the water is carried too high in the 
 
EVAPORATORS AND DISTILLERS 125 
 
 glass, it will boil up and, mixing with the steam, will be car- 
 ried over with it. For some reason the water in an evaporator 
 foams more than it does in a boiler of the same size, hence 
 its height must be watched carefully, and all evaporators 
 should be fitted with baffle plates and dry pipes. If the de- 
 tilled water is being run into a tank for the use of the ship, a 
 little carelessness in allowing the salt water to lift might re- 
 sult in spoiling a whole lot of good drinking water. 
 
 "After the steam is generated in the evaporator, it is usually 
 passed into the main condenser, where it is condensed into 
 water along with the exhaust steam from the engine, and thus 
 makes up the deficiency in the feed water." 
 
 "Where does this distilling business come in?" inquired 
 Nelson. 
 
 "Oh, yes," replied McAndrew, "I almost forgot to tell you 
 that on shipboard, as well as on shore, the distiller is used 
 for drinking purposes, only that the ship's product is exclu- 
 sively pure water. A ship's distiller is in reality only a small 
 condenser, and is usually made of copper or brass; the sea 
 water is used for cooling purposes, and, passing on the out- 
 side of a number of small brass or Muntz metal tubes, which 
 have been carefully tinned, condenses the steam from the 
 evaporator into fresh water, which is run into tanks and used 
 for drinking or culinary purposes." 
 
 "I know all about the drinking end of it, but what's this 
 'culinary' stunt?" inquired O'Rourke. 
 
 "If you ever hung around the galley any, you must have 
 noticed that the cook uses considerable fresh water to make 
 coffee, soup, etc," replied McAndrew; "that's 'culinary' per- 
 haps I should have said 'cooking' purposes." 
 
 "Oh ! I see," said O'Rourke ; "the difference between 'cul- 
 inary' and 'cooking' is about the same as the difference be- 
 tween a 'cook' and a 'chef.' " 
 
 "To return to the subject. I forgot to tell you that the feed 
 
^26 MC ANDREW'S FLOATING SCHOOL 
 
 water for the evaporator should not be taken from the sea 
 direct, as it has to be heated up to the boiling temperature, so 
 it is customary to take it from the discharge water from the 
 main condenser, which has already been heated up to between 
 120 and 140 degrees; there is thus a considerable saving of 
 heat units by using the discharge water instead of the cold 
 sea water. 
 
 "Some ships have several evaporators in series, the steam in 
 the first one being raised to 60 or 80 pounds pressure and 
 then passed along to the next evaporator, where it is used to 
 generate steam ; the steam in the second evaporator is carried 
 at a pressure of from 10 to 15 pounds, and this, in turn, is 
 used to generate steam in a third evaporator, wherein the 
 steam is sometimes at a pressure below that of the atmosphere, 
 but it readily flows into the main condenser, where the vacuum 
 is less. Such an apparatus is known as a triple-effect evapo- 
 rator, and there is a considerable saving by such means. How- 
 ever, the first cost is so great that it is but seldom used. 
 
 "I must also tell you of a good wrinkle in scaling an evapo- 
 rator where the coils are of the spiral type. A sudden change 
 of temperature will tend to crack the scale, so that by a slight 
 tapping with a wooden mallet it will drop off readily. To ob- 
 tain this sudden change of temperature, the evaporator should 
 be emptied of all water and steam turned on the coils until 
 they are as hot as it is possible to get them. Then start your 
 evaporator feed pump up as fast as it will run, open the bot- 
 tom blow to the evaporator, and the valve connecting the 
 evaporator to the main condenser, if there is a vacuum in it. 
 The cold sea water will then rush in at such a rate as to give 
 the sudden change in temperature desired. This effect can 
 also be brought about by heating up the coils, taking off the 
 lower manhole plate of the .evaporator, if such is provided, 
 and then turning the fire hose on the coils." 
 
CHAPTER XV 
 
 Electricity 
 
 "One of the most important of the auxiliaries on board a 
 modern steamer is the dynamo for generating electric current 
 for lighting and ventilation purposes. The study of electricity 
 presents a very large subject in itself, but it is essential that 
 all marine engineers have at least a fair insight into the general 
 principles involved. I will therefore give you a few hints on 
 the subject which will, I hope, be of interest and benefit to you. 
 
 "In commencing my remarks on the subject, I will ask if 
 any of you know what electricity is ?" 
 
 A silence followed this question, which was finally broken 
 by O'Rourke, who said, "I did know once, but I have clean 
 forgotten it." 
 
 'Too bad ! Too bad, entirely," said McAndrew ; "what a 
 loss to the scientific world ! To think that you once knew the 
 mystic key to this great question which no living man has ever 
 solved, and that you have forgotten it ! You certainly should 
 be punished for such monumental carelessness in keeping from 
 the public the true answer to this hitherto unanswered problem. 
 Well, we will have to continue in our ignorance, and although 
 no one but O'Rourke has ever really known what electricity is, 
 we, in common with all others, will have to devote our atten- 
 tion to studying its effects. 
 
 "The name 'electricity' comes from the Greek word 'elec- 
 tron,' meaning amber, as it was from rubbing this material 
 with a catskin that the phenomenon was first noticed. There 
 are three principal ways of generating this current, as it is 
 
128 MC ANDREW'S FLOATING SCHOOL 
 
 generally termed. The first might be termed 'frictional elec- 
 tricity,' as it is generated by rubbing such substances as glass 
 and silk together; you may also have noticed its effect by 
 scuffling your feet on a woolen carpet and then touching some 
 metal, such a a gas jet or brass bed, when you can generally 
 see, hear and feel a slight electric shock. This method of 
 generating electricity is not, however, used practically. 
 
 'The second method might be termed 'chemical electricity,' 
 from the fact that a current is set up by immersing two differ- 
 ent metals in a chemical solution. Copper and zinc are most 
 commonly used, as it is found, when these metals are immersed 
 in a mild solution of sulphuric acid, a pronounced flow of elec- 
 trcity is set up between them. This combination is known as 
 a cell. 
 
 "A number of cells form a battery, and electricity from such 
 a source is largely used for operating telegraph lines, alarm 
 bells, etc. What are known as 'dry batteries,' wherein elec- 
 trcity is formed by the chemical decomposition of zinc in the 
 presence of carbon surrounded by a paste made of plaster, 
 flour or chemicals, are particularly useful on shipboard, as 
 there is no liquid to be spilled by the rolling of the ship. 
 
 "The third method of generation might be termed the 'mag- 
 netic system.' You all know of and have played with the ordi- 
 nary toy horseshoe magnet. The two ends of a magnet are 
 known as 'poles,' and you no doubt have observed that there 
 is an unseen force acting between these poles, sufficiently 
 strong to attract or pick up small pieces of metal, and that it 
 is particularly strong in picking up iron or steel. This ability 
 of attracting pieces of metal is attributed to what are known 
 as lines of magnetic force' which exist in the magnet. Some 
 of the early experimenters discovered that if certain combina- 
 tions of wires were revolved between 'these poles of a magnet 
 or the 'magnetic field,' as it is called a current of electricity 
 would be set up. Proceeding on this principle, the modern 
 
ELECTRICITY 
 
 129 
 
 dynamo has been evolved. I will not attempt to mystify you 
 by going into the theory of how this is done, as I feel quite 
 sure that after I had finished you would probably have a hazier 
 idea than you had before, so I will confine my remarks to some 
 of the practical things which you should learn about the sub- 
 ject. 
 
 'This 'magnetic system* of producing electricity is used al- 
 most exclusively for all lighting and power purposes. The 
 modern dynamo for producing current is to all intents and 
 purposes a large magnet, and the bunches of wires revolving 
 between its poles, and hence cutting the 'lines of force,' is 
 known as the 'armature.' The current is collected by what are 
 known as 'brushes,' generally blocks of carbon, held against 
 the revolving metal. 
 
 "I do not expect you to grasp the idea of electricity imme- 
 diately, as very few people do, but it will probably help you 
 somewhat to compare it with water in a pipe system. In such 
 a comparison we will consider the dynamo as a pump forcing 
 water through a continuous line of pipe of varying diameter, 
 according to the flow desired. We will suppose that the main 
 leading away from the force pump is divided up into several 
 branches, and that from each of these branches there are 
 numbers of small spigots from vhich the water is being drawn. 
 We all know that no water will flow from the outlets unless a 
 pressure is put on by the pump. We also know that this water 
 is being used at the various outlets, and that we can deter- 
 mine how many gallons per minute is being used if we so 
 desire. You can also readily understand that the water will 
 not flow through the pipe line as readily as it would if simply 
 pumped overboard directly from the discharge valve, on ac- 
 count of the friction of the water as it slides or flows over the 
 inner surfaces of the pipes. Now we must imagine that elec- 
 tricity is being used instead of water. The wires, proportioned 
 according to the amount of flow required, take the places of 
 
13 MC ANDREW'S FLOATING SCHOOL 
 
 the pipe and its branches. The electric lights, distributed along 
 the branches, take the places of the spigots in the pipe line." 
 
 "The pressure of the water corresponds to what is known 
 as 'electro-motive force' for electric currents, and the unit is 
 known as the 'volt.' Thus we have on the switchboard of all 
 electric plants a Voltmeter,' which corresponds to the pressure 
 gage in a pipe line ; in other words, we read the electric press- 
 ure from the voltmeter, and it is well to note that the standard 
 pressure for lighting currents on shipboard is no volts. 
 
 "The resistance to the flow of water through pipes corre- 
 sponds to the resistance of the flow of electricity through 
 wires, and the unit of this resistance is called an 'ohm.' 
 
 "The rate with which water flows through a pipe in a given 
 time is expressed in so many gallons per minute ; in electricity 
 the rate of flow is expressed in a unit known as an 'ampere,' 
 which means the amount of current produced by a pressure of 
 one volt acting against a resistance of one ohm. 
 
 "Electric power, like mechanical power, must take into con- 
 sideration the element of time, and the unit of this kind of 
 power is known as the 'watt,' which is the power produced by 
 a current of one ampere at a pressure of one volt for one 
 second." 
 
 "Where do they get all these funny names like volt, ampere 
 and ohm?" inquired Pierce. 
 
 "They are derived from the names of the early scientists who 
 studied this subject, and in this way their fame will be handed 
 down to future generations. Volt conies from the Italian 
 named Volta, who was an early experimenter in the subject. 
 Ampere was another early scientist, and you ought to know 
 that Watt was the inventor of the steam engine. If you had 
 been around in those days, and made the experiments, the unit 
 of pressure might have been a 'pierce' instead of a 'volt.' " 
 
 "I'll bet," said Smith, "that the unit of resistance or friction 
 
ELECTRICITY !^ z 
 
 would have been an 'O'Rourke' if he had been around in those 
 days." 
 
 "One thing sure," replied McAndrew, "the unit of work 
 
 'ampere' would never have been displaced by anything that 
 sounded like an 'O'Rourke.' 
 
 "The 'watt' is a much smaller unit than the horsepower, 
 and, in fact, it takes, theoretically, 746 watts to equal one 
 horsepower. That doesn't mean that a one-horsepower engine 
 would produce that many watts, as there are too many losses 
 between the two, but it is known as the theoretical equivalent. 
 In speaking of the rated power of a dynamo or generator, the 
 general term is 20 K.W., 50 K.W., etc., as the case may be. 
 The K. means kilo, the Greek word for one thousand, so that 
 a 20 K.W. machine means one that is capable of producing 
 20,000 watts. 
 
 "To utilize electricity for lighting purposes, it was necessary 
 to invent an electric lamp, and this fell to the lot of Edison, 
 an American inventor, who, after many months of experiment- 
 ing, found that a filament of carbonized bamboo, placed in- 
 side a glass bulb from which all the air had been exhausted, 
 would heat up to an incandesence when an electric current was 
 passed through it. If the air is not exhausted from the bulb, 
 the oxygen in the air would cause combustion, which would 
 burn up the filament almost instantly. Many metallic sub- 
 stances are now used for filaments, and are known as 'tung- 
 sten,' 'mazda,' 'tantalum,' etc. These are much more efficient 
 than the old-style carbon-filament lamps, that is, they give 
 much more light for the same amount of current used. The 
 ordinary carbon-filament i6-candlepower lamp is generally 
 used on shipboard ; this lamp requires about H ampere of cur- 
 rent or 55 watts. If we know the voltage of a current and 
 the amperage, how do we tell how many watts will be used?" 
 asked McAndrew of the class. 
 
132 MC ANDREW S FLOATING SCHOOL 
 
 "Wait until you get the bill from the electric lighting com- 
 pany," suggested O'Rourke. 
 
 "You can't be too sure of that," replied the instructor, "as 
 most people have an idea that gas bills and electric light bills 
 are not made out on a strictly scientific basis. The right way to 
 ascertain that fact is to remember that the watts are equivalent 
 to the volts multiplied by the amperes. In this case we have 
 no x */>, which equals 55. If we were using 20 amperes of 
 current at a pressure of 10 volts the result would be 20 x 10, 
 or 200 watts. 
 
 "An ordinary i6-candlepower lamp, using 55 watts of cur- 
 rent, will require, on an average, i-io horsepower at the gen- 
 erating engine, so I want to impress upon you the importance 
 of turning off electric lamps which are not needed in any 
 part of the ship, as they soon eat into the coal pile to a con- 
 siderable extent, for every hour that a i6-candlepower lamp 
 is burned there is nearly a pound of coal used under the 
 boilers. 
 
 "I want to call your attention to the instruments used on 
 the switchboard, which is the name of the apparatus by means 
 of which the current is distributed. The whole electric light 
 system is divided up into circuits or branches, corresponding 
 to the different parts of the ship. For example, there is usually 
 a complete circuit for the engine room, one for the fire room, 
 one for the social hall, etc. If these were water-pipe connec- 
 tions there would be a valve in the pipes at both ends of the 
 circuit. For electricity, what is known as a switch or cut-out 
 is used, and generally located on the switchboard. They are 
 usually of the double pole type, that is, they cut out both the 
 sending side and the return side simultaneously. 
 
 "Unlike water, electricity is liable to sudden fluctuations of 
 both pressure and volume ; unless some means of easement is 
 provided, damage is liable to result to the wiring or fixtures. 
 Hence at various points in the circuit the current is made to 
 
ELECTRICITY 133 
 
 pass through short lengths of some fusible alloy, which, when 
 subjected to an unusual current, melts and breaks the circuit. 
 These are made in two types, the link and cartridge ; one is a 
 plain wire, and the other is a wire encased in a fiber tube. 
 The action in this case is similar in effect to the blowing off 
 of a safety valve. 
 
 "The ammeter is an instrument for indicating by a needle on 
 a dial the amount of current being used, which varies, of 
 course, with the number of lights and fans in use. 
 
 "The voltmeter, or pressure gage, has the same function as a 
 steam gage on the boiler. 
 
 "The rheostat is an instrument for using up surplus energy 
 or current, and consists of a series of coiled wires which can 
 be connected up in the circuit by moving a handle across the 
 contact points. You probably know that when the main engine 
 of a ship is required to run slowly, and the boilers temporarily 
 making more steam than can be handled by the engine, it is 
 customary to open what is known as the 'bleeder valve' from 
 the main steam pipe, which allows the high-pressure steam to 
 blow directly into the condenser. This is practically the same 
 purpose for which the rheostat is used, the surplus current be- 
 ing dissipated by the increased resistance of the coils of wire 
 which disposes of the electric energy in the form of heat. 
 
 "Now a word about wiring to transmit the current to the 
 points where it is needed. As copper offers less resistance to 
 the flow of electricity than any other metal of reasonable cost, 
 it is used almost universally. In laying out the wiring for the 
 ship, the sizes are determined to suit the quantity of electricity 
 to be used in about the same manner that we would proportion 
 piping for the distribution of steam or water. Small wires 
 are made single, and for larger currents it is customary to use 
 a number of small wires either parallel or laid up in the form 
 of a cable. On shipboard it is of the first importance that the 
 wires should be well insulated, that is, covered with a sub- 
 
134 
 
 MC ANDREW S FLOATING SCHOOL 
 
 stance which prevents entirely, or to a large extent, any flow 
 of electricity through it. The best and most used of such sub- 
 stances is ordinary rubber covered with braided silk or cotton 
 to make the whole covering waterproof. Water is an ex- 
 cellent conductor of electricity, and hence any leakage through 
 the covering on the wires will rapidly result in corrosion of 
 the wires and leakage or short circuiting of the electric cur- 
 rent. In the first marine electric installations the wires were 
 run in wooden strips, but as it was difficult to keep them tight, 
 
 HHHH 
 
 FIG. 24. DISTRIBUTION IN PARALLEL 
 
 the almost universal practice now is to run electric wires in 
 iron pipes known as conduits. Porcelain is another excellent 
 non-conductor of electricity, hence we find that material used 
 for various kinds of electric fittings and lamp sockets. 
 
 "The wires for electric lights on ships are usually run in 
 what is known as 'parallel,' as shown in Fig. 24. 
 
 "Each lamp, you will notice, is tapped off between the two 
 wires, so that each will draw a sufficient amount of electricity 
 from the main to run the particular lamp. 
 
 "Other uses than for lighting on shipboard are fan motors 
 and winch motors." 
 
ELECTRICITY 
 
 135 
 
 "What is a motor?" inquired one of the class. 
 
 "A motor," said McAndrew, "is simply a small dynamo run- 
 ning backwards. Electric fans are driven by means of the 
 current passing through the wire wound around the magnetic 
 poles, which causes the armature to revolve. The fan blades 
 are secured to an extension of the armature. If the small 
 armature was made to revolve by an engine or other source of 
 power, the motor would generate electricity instead of using 
 it up, and hence become a small dynamo. 
 
 "In closing my remarks on electricity, I want to impress 
 upon you that, although it is not known definitely what it is, 
 its effects are very well known, and there is no great mystery 
 about it. You do not get something for nothing, as many be- 
 ginners are apt to think. For all electrical energy generated 
 and used, there is a still greater amount of mechanical energy 
 exerted in its production. If the current comes from a bat- 
 tery, you have to produce it by the disintegration or wasting 
 away of the zincs ; if from a dynamo, it takes coal to produce 
 it. The only free electricity we get is that from the clouds in 
 the form of lightning, but no one has, as yet, found a method 
 of utilizing currents from that source." 
 
 "What about Jersey lightning?" inquired O'Rourke. 
 
 "I suppose you refer to the New Jersey drink known as 
 'applejack,' and if that's the case, I haven't heard that that is 
 free, either, but I understand its results are about as fatal as 
 the lightning we get from the clouds. You probably know 
 more about that than any of the others here." 
 
CHAPTER XVI 
 
 Pipes and Valves 
 
 'The school will be in order," demanded McAndrew, as he 
 entered "Highbrow Hall," it having been dubbed that by 
 O'Rourke. The cause of this remark was a heated discussion 
 which was being carried on by the four students as to whether 
 the United States or Germany had the larger navy. Gus 
 Schmidt and Nelson were maintaining that Germany was the 
 more powerful, while Pierce and O'Rourke strenuously in- 
 sisted that Uncle Sam was the superior on the water. 
 
 "Never mind about the navies of the world," said the in- 
 structor, "they're big enough to look after themselves what 
 you boys should be interested in is to be of some use to the 
 merchant marine. I want to discuss this evening the subject 
 of pipes and valves. We have dealt with boilers, engines, 
 pumps, etc., and now we want to connect them up. This is, 
 therefore, a very important matter, as much depends in the 
 successful operation of marine machinery on having proper 
 pipes to carry the steam and water and proper valves to con- 
 trol them. Piping on board ship can be divided into three gen- 
 eral classes, i. e., steam pipes, exhaust pipes and water pipes. 
 
 "The main steam pipe system is naturally of the greatest 
 importance, as through this system the steam is passed from 
 the boilers to the main engine. 
 
 "The material generally used for the main steam pipe is 
 copper, on account of its great ductility, the ease with which 
 it is worked and its freedom from corrosion. For sizes up to 
 10 and 12 inches in diameter it is made of seamless drawn 
 
PIPES AND VALVES 
 
 137 
 
 material in order to avoid the brazed seam, which is liable to 
 be the cause of leakages. As copper expands or increases in 
 length when heated up to the temperature of the steam it car- 
 ries, great care is exercised by designers to make arrangements 
 for this expansion to be taken up without damaging the pipe 
 or its flanges. One method of accomplishing this is by means 
 of the ordinary 'slip joint,' as shown in this sketch. 
 
 FIG. 25. EXPANSION JOINT 
 
 "These, however, cause considerable work in order to have 
 them properly packed, and have been known to pull apart and 
 scald people who happened to be in the vicinity. The best 
 method is to lay out the pipes so that there will be a number 
 of large curves or bends in their length ; the expansion then 
 being taken up by the slight bending of the pipes. That is the 
 reason you never see a large steam pipe run straight. As all 
 pipes must be in such lengths as to get them in and out of the 
 spaces they occupy for the purpose of making repairs, the sec- 
 tions must be securely bolted together. This, you may have 
 noted, is accomplished by expanding the ends of the pipes 
 into rings of cast iron or composition, called flanges, and after 
 putting in some packing between the flanges, they are bolted 
 up tightly together by means of a number of bolts of sizes to 
 suit the diameter of the flanges. The making and keeping 
 tight of these pipe joints is one of the most serious parts of an 
 engineer's business. Various kinds of patented packings are 
 used for making these so-called 'gaskets' for pipe joints; many 
 
138 MC ANDREW'S FLOATING SCHOOL 
 
 of them are excellent, some are good, and others are not worth 
 two hoots. You will each have to learn from your own ex- 
 perience which is the best material to use, but be sure and get 
 the kind which keeps the tightest joint and lasts the longest." 
 
 "Which one is that?" inquired Nelson. 
 
 "Ask each packing agent who tries to sell you some, and 
 you will find that he has the goods," was the reply. "Some 
 night when you are compelled to work an extra watch to re- 
 place a blown-out joint over the top of a hot boiler, just make 
 a record of your thoughts regarding that particular kind of 
 packing, and when you get back in port show it to the agent 
 whom you patronized." 
 
 "Wouldn't we have to write those thoughts on some asbes- 
 tos paper?" inquired O'Rourke. 
 
 "I think you would," said McAndrew. 
 
 "Main steam pipes on some vessels carrying very high-pres- 
 sure steam are made of seamless drawn steel, on account of its 
 strength being greater than that of copper. The disadvantages 
 of steel for piping are the difficulty in making easy bends and 
 its liability to corrosion. The flanges on steel pipes are some- 
 times made solid with the pipe, and this makes the strongest 
 job obtainable for a joint of this kind. 
 
 "Auxiliary steam piping is made of copper, brass, iron or 
 steel, according to the class of work. Seamless drawn copper 
 is about the best that can be used, while ordinary wrought iron 
 piping with screwed joints is often used in the cheaper kinds of 
 work. 
 
 "Exhaust piping for steam is made of copper or iron, and it 
 only differs from steam piping in being made thinner, as it does 
 not have to withstand so high a pressure. 
 
 "Speaking of iron piping, O'Rourke, did you ever see a piece 
 of ^$-inch pipe?" 
 
 "Lots of it," replied the ever-ready. 
 
 "Well, I'm glad to hear it," said McAndrew, "you are prob- 
 
PIPES AND VALVES 139 
 
 ably the only one living who has ever seen that size ; as a 
 matter of fact pipe manufacturers do not make any %-inch 
 pipe or any ^g-inch pipe, either. Just why they don't I am 
 unable to say, but the old-timers who originated pipes for use 
 around gas works probably had good reasons for not doing 
 so. 
 
 "Just jot this down in your memories: Pipe sizes are ]/& 
 inch, *4 inch, fy& inch, y 2 inch, ^4 inch, i inch, \y\ inches, i l /t 
 inches, 2 inches, 2 l / 2 inches, 3 inches, 3^ inches, 4 inches, 4^ 
 inches, 5 inches, and above that in even inches. If any one 
 ever tells you to go and get them a piece of i^-inch pipe, or 
 any other size which is not in the list I have given you, they 
 are trying to run you. Just tell them that the storekeeper is all 
 out of that particular size. 
 
 "If any one ever asks you the diameter of a i-inch pipe, don't 
 think that it is a similar question to 'What times does the 
 12 o'clock train leave?' for it is not. While the 12 o'clock 
 train may leave at 12 o'clock, a i-inch pipe is always 1.05 
 inches inside diameter; a ^-inch pipe is .62-inch inside diam- 
 eter, or nearly ^ inch. Here, again, the old-time gas engineers 
 got in their work ; but if you don't like standard sizes you can 
 go without them; they have come to stay, and you might as 
 well try to buy cheese by the yard instead of by the pound as 
 to get manufacturers to change these old-established standards. 
 
 "For high pressures, pipes are made 'extra heavy' and 
 'double extra heavy/ but the outside diameters are the same, 
 the excess metal being put on the inside. 
 
 "Brass pipes are made of iron-pipe size, and are frequently 
 used in small-sized steam and exhaust pipes. Iron and brass 
 pipes are not bent so easily as copper pipes, hence to change 
 direction in a pipe lead, or to reduce or increase sizes, various 
 standard fittings are used. These, naturally, are made of what 
 is known as 'malleable iron' a cast iron which is not as 
 brittle as ordinary cast iron. Hence if the lead of the pipe is 
 
140 MC ANDREW'S FLOATING SCHOOL 
 
 to change at right angles, an 'elbow' is used ; if one pipe is to 
 branch off at right angles to another pipe, a 'tee' is used; if 
 two pipes are to be joined together for permanent use, a 
 'coupling' is used; if sections of piping are to be put up so that 
 they can be taken down, 'unions' are used, and let me say 
 right here that for marine work you can't use too many 
 'unions,' as they're mighty handy fittings ; then there are 
 'plugs,' 'caps/ 'reducers,' and various other devices for the 
 .convenient installation of piping, all of them made with stand- 
 ard pipe threads. 
 
 "For water piping on board ship, copper is almost always 
 used for pipes which handle salt water, although in some cases 
 for bilge pipes, lead is used. Copper has the advantage of not 
 being corroded by salt water, and as it can be bent easily it 
 makes an ideal material for such purposes. For the feed pipes, 
 seamless drawn brass is frequently used for the straight parts 
 and copper pipe for the bends. For the fire main seamless 
 drawn brass is the best material, but as this is very expensive 
 it is seldom used. A very good substitute material for use as 
 fire mains is wrought iron or steel lined with lead. The iron 
 or steel furnishes ample strength to resist the pressure, and 
 the lead lining prevents corrosion of the interior, providing 
 always that no leaks develop through the lining." 
 
 "What do you mean by 'seamless drawn ?' " asked one of the 
 class. 
 
 "When pipes were first made they were rolled up into cylin- 
 drical form out of sheet metal, and the seam brazed in the case 
 of copper and riveted for iron or steel. A joint of either kind 
 is an element of weakness, and leaks frequently start from 
 imperfections in the welding or brazing of the joint. Of late 
 years the art of drawing metal pipes from a solid block or 
 ingot over a mandrel has taken great strides, so that to-day it 
 is possible to buy either steel or copper pipes of any size up to 
 12 inches and over in diameter which have been drawn solid, 
 
PIPES AND VALVES 141 
 
 and consequently have no seams. Although at present the 
 larger sizes of seamless pipe cost more than built-up pipes, 
 the greater safety, due to the absence of joints, makes it ad- 
 visable to use this pipe, especially for steam and water piping 
 subjected to high pressures. 
 
 "In main feed pipes on board ship it is always necessary 
 to make them in several lengths to facilitate their installation 
 in crowded spaces, and to make them accessible for repairs. 
 The location of flanges joining these sections together should 
 be very carefully planned out in order to provide freedom of 
 access in making new joints. When a leak occurs in a feed 
 pipe joint it must be repaired very quickly, as boilers under 
 steam won't run long without water. Every .boiler is, of course, 
 provided with both a main and an auxiliary feed connection, 
 but no engineer ever feels very comfortable while even one of 
 these pipe connections is out of order. 
 
 "Bilge pipes are sometimes made of lead, as I previously 
 stated, but more often they are made of galvanized iron on 
 account of the less cost. In connection with bilge piping it will 
 be well to tell you something about the methods of getting 
 water out of a ship's bilge, as every marine examiner will ask 
 you something about that. The usual form of the question is, 
 'State how many means there are for getting water out of the 
 bilges ?' Perhaps you can answer it off-hand, O'Rourke." 
 
 "Sure," said that worthy. "Start the donkey pump, and if 
 that doesn't do the trick put the firemen to work bailing it out 
 with buckets." 
 
 "Starting the donkey pump would do for ordinary circum- 
 stances, but in an emergency, if you were put to work bailing 
 out the bilges, I am afraid the ship would sink before you 
 carried more than two or three bucketsful up the ladders ; that 
 is, if you didn't work any faster than you usually do. 
 
 "The usual method of pumping out bilges is by the inde- 
 pendent bilge pump with which most ships are furnished. 
 
142 MC ANDREWS FLOATING SCHOOL 
 
 This pump can be connected to all compartments of the ship 
 through the manifold, from which pipes lead to all bilges. You 
 may have noticed that valve near the circulating pump which 
 is always kept closed, and should be locked or tied shut. In a 
 great emergency, such as the ship grounding or in collision, the 
 main circulating pump can be connected so as to pump out the 
 bilges, by closing the main injection valves, and opening this 
 emergency or bilge injection valve, as it is termed. On most 
 ships the auxiliary, or donkey pump, usually is connected to the 
 bilge manifold, so that it may also be put to pumping out the 
 bilges. 
 
 "Many ships are provided with what is known as a 'bilge 
 ejector,' whereby a -jet of steam starts and maintains a syphon 
 effect which forces the bilge water up and overboard. Such a 
 contrivance is too wasteful of steam, and consequently of fresh 
 water, to be used very freely on vessels plying the ocean. If 
 all these devices fail to keep the water in check, then the best 
 thing you can do is to pack your grip and take to the boats." 
 
 "How about saying your prayers ?" inquired O'Rourke. 
 
 "I don't think that would work in your case," retorted 
 McAndrew. 
 
 "A very important point in connection with pumping out 
 bilges is to see that the strainers are cleared. The bilges of all 
 ships, as you may know, usually contain ashes, chunks of waste, 
 shavings and other refuse, and they have been known to con- 
 tain a fireman's undershirt or overalls. These things if drawn 
 into the bilge suction pipes would soon choke them up and the 
 pumps would be useless. Hence it is that the end of every 
 pipe is fitted with some form of a perforated strainer to catch 
 the refuse before it can get into the pipes. The ordinary form 
 is known as the box strainer, which, as its name indicates, is 
 shaped like a box, and has all its sides and its bottom per- 
 forated with three-eighths or one-half inch holes. The top of 
 the box is made easily removable so that it can be cleaned out. 
 
PIPES AND VALVES 
 
 143 
 
 Unless given attention frequently these strainers themselves 
 become plugged up with dirt and refuse, and you young men 
 will probably never appreciate the importance of keeping them 
 cleaned out until you are called on some night while the ship 
 is rolling and pitching in a gale of wind to dive down in bilge 
 water up to your armpits for the purpose of digging bunches 
 of waste and handfuls of ashes out of the strainer boxes. An 
 old-time chief engineer in the navy conferred a lasting boon 
 on seafaring men by inventing what is known as the 'Macomb 
 strainer,' a device whereby the water is strained through a 
 metal basket in a cast iron body with a removable top. By 
 simply removing a clamp in the top of the strainer body the 
 basket can be lifted out and emptied in two minutes. This in- 
 vention has saved much profanity on shipboard, and probably 
 many ships. 
 
 "In line with a talk on piping, and incidentally with pro- 
 fanity-provoking devices, we might stop casually and consider 
 the steam trap, a necessary evil fitted to all steam plants. The 
 primary purpose of a steam trap is to separate the water from 
 steam in the numerous drains with which all marine machinery 
 must be fitted. This is accomplished, or, I might add, is tried, 
 to be accomplished, in two principal ways : one by the auto- 
 matic filling and emptying of buckets floating in the water 
 of condensation, and the other by difference of expansion in 
 metals as affected by the variance in the temperatures of steam 
 and water. There are about as many different styles of steam 
 traps as there are applicants for an easy job, but there are not 
 more than two or three of these styles fit to use on board ship. 
 I hesitate to tell you which they are, as I am a little uncertain 
 even about their efficiency at all times. 
 
 "Of equal importance to the piping on board ship are the 
 valves which control the flow of steam and water through 
 them. Most of the work of the engineer, while the vessel is 
 under way, is devoted to the opening, closing and regulating 
 
144 
 
 MC ANDREWS FLOATING SCHOOL 
 
 of valves. Knowing how and when to perform these functions 
 constitutes a large part of an engineer's practical knowledge. 
 The efficient working of marine machinery is largely dependent 
 upon the proper manipulation of valves, and on the other hand 
 nine-tenths of all the trouble on board ship is occasioned by 
 the wrong manipulation of these important details. With this 
 
 FIG. 26. GLOBE VALVE 
 
 introduction to the subject you can readily see that it will be 
 well to pay a little attention to them. The valves used on ship- 
 board may be divided into principal classes angle and globe, 
 stop and check, and gate valves, and various combinations of 
 these types. 
 
 "A globe valve may be denned as one in which the steam, 
 water, etc., enters and leaves the valve flowing in the same 
 direction; an angle valve is one in which the steam, water, etc., 
 enters the valve flowing in one direction and leaves the valve 
 
PIPES AND VALVES 
 
 I4S 
 
 flowing in a direction usually at right angles to that in which 
 it enters. Figs. 26 and 27 will illustrate these two types. 
 
 "A stop valve is one in which the disk is under absolute 
 control of the hand wheel, and permits of flow through it in 
 either direction. 
 
 FIG. 27. ANGLE STOP VALVE 
 
 "A check valve is one in which the stem is not connected 
 with the disk, and permits of flow through it in only one 
 direction. It can, however, be shut off by screwing down on 
 the hand wheel. 
 
 "A gate valve is one in which the disk or gate is set at right 
 angles to the direction of flow, and is at all times under control 
 of the hand wheel. (See Fig. 28.) 
 
 "A cock is in reality a valve of the simplest design, wherein 
 a conical plug is fitted in the body, and the flow of steam or 
 water through it is regulated accordingly as the slit through 
 
146 
 
 MC ANDREW S FLOATING SCHOOL 
 
 the plug is placed in line with the direction of the flow or at 
 right angles to it. 
 
 "Valves of all descriptions are made principally of the best 
 quality of cast iron, as that is the cheapest and best adapted 
 metal for the purpose. Composition is frequently used for 
 small valves and for larger valves in high-class work, on ac- 
 
 SECTIONAL ELEVATION 
 
 FIG. 28. GATE VALVE 
 
 SECTIONAL PLAN 
 SHOWING BY-PASS 
 
 count of its freedom from corrosion and greater strength. Its 
 increased cost, however, precludes its extensive use. 
 
 "Cast steel is used to some extent for valves subjected to 
 very high steam pressures, owing to its great tensile strength, 
 but the difficulty of obtaining good castings, free from blow- 
 holes, limits its use to places where the greater strength is 
 absolutely necessary. 
 
 "It is usual to have all cast iron valves 'brass mounted'; 
 that is, to fit them with composition seats, disks, stems and 
 
PIPES AND VALVES 147. 
 
 stuffing-boxes, as these are the parts subjected to the greatest 
 wear. 
 
 "Seats of valves become grooved by the constant flow of 
 steam or water, and if not attended to regularly are bound 
 to leak. Therefore one of the frequent duties of an engineer is 
 to 'grind in' leaky valves, an operation which consists of re- 
 moving the valve covers, covering the seats with a ground- 
 glass paste and revolving the disk in place until all grooves are 
 removed. A valve reseating machine is a device for 'grinding 
 in' valves mechanically while in place, the same as it would be 
 done if the valve was removed and placed in a lathe. Such a 
 device is a necessity in order to keep valves on a modern ship 
 always tight." 
 
 "Chief, what is a reducing valve used for?" interrupted 
 Pierce. 
 
 "Reducing valves are of comparatively recent use around 
 steam plants, and have been made a necessity by the constantly 
 increasing steam pressures now being used on board ship. 
 While these high pressures are necessary for multiple-cylinder 
 main engines to increase the economy of working, there are 
 still certain auxiliaries on all ships which use lower steam 
 pressures. Among these may be mentioned the ordinary recip- 
 rocating dynamo engines, the steering engine, the windlass 
 engine, the bilge pumps, the heating apparatus, steam jackets, 
 etc., and, in fact, wherever it is desirable to have low-pressure 
 steam at a uniform pressure. These are devices whereby the 
 high-pressure steam from the boilers may be reduced and 
 delivered at almost any pressure desirable by regulating the 
 reducer, after which, no matter how much the boiler pressure 
 may fluctuate, a steady lower pressure is maintained for the 
 auxiliaries." 
 
 "What is a relief valve, and why are they fitted on some 
 pumps?" inquired Schmidt. 
 
 "A relief valve is simply a small safety valve," replied 
 
148 MC ANDREW'S FLOATING SCHOOL 
 
 McAndrew. "I have already told you why these are useful 
 on the main engines. On some pumps, and especially fire 
 pumps, it frequently happens that a careless oiler or machinist 
 will start the pump full speed, and if there are not sufficient 
 openings of the stop valves along the fire mains the pressure 
 might rupture the pipe. For that reason one or more relief 
 ' safety valves, set to blow off at a safe pressure, are fitted in the 
 fire main, usually in the engine room, where the escaping water 
 can do no particular harm. 
 
 "I have already explained to you that a valve need only be 
 opened a vertical distance equal to one-fourth its diameter, 
 and I hope you will bear that fact in mind. Remember, also, 
 what I told you about not opening a steam valve quickly. 
 That, however, does not apply to water valves, as they should 
 be opened as quickly as possible. 
 
 "In closing this lecture I will call your attention to the pipe 
 covering. In general all pipes transmitting either steam or hot 
 water should be covered with non-conducting material, such as 
 hair-felt for low pressures, and magnesia or asbestos, or the 
 various components of each for the higher temperatures. Es- 
 caping heat not only lowers the efficiency of any steam engine, 
 but it adds to the discomfiture of the men who have to operate 
 the machinery. If you ever have to do any pipe covering 
 remember that you should not cover any of the joints, as it is 
 often necessary to get at them quickly to make new joints, or 
 to set up on them when they leak. All pipe covering should 
 be encased in canvas, and it should be sewed on instead of 
 being pasted, as some contractors like to do. 
 
 "We have about covered in a general way all parts of a 
 marine installation, and from now on I will direct your atten- 
 tion to what may be termed specialties, and go into a number 
 of subjects with which you will have to be familiar before 
 getting your ticket." 
 
CHAPTER XVII 
 
 Indicator Cards and Horsepower 
 
 "My subject this evening will be indicating cards," re- 
 marked McAndrew, as his class gathered in the improvised 
 school room after a hard day's work in connection with low- 
 ering two of the new boilers of the Tuscarora in place. 
 
 "Do you know what a steam engine indicator is?" he in- 
 quired, looking at O'Rourke, who he surmised would be the 
 first to give a reply. He was not disappointed, as that young 
 man immediately volunteered the information that "an indi- 
 cator, sir, is a nickel-plated machine that looks something like 
 a pickle castor ; you screw it into the outside of a cylinder, tie 
 a string to its tail, let it sneeze three or four times, then un- 
 wrap a piece of paper from the outside, which you carry up to 
 the chief engineer, who looks wise, fixes his 'specs,' and de- 
 livers the opinion that she's got too much compression, what- 
 ever that is." 
 
 "That's a fine description, O'Rourke, and shows that you are 
 a man of keen perception, especially as to the 'look wise' part 
 of the performance. The appearance of knowing all about it 
 seems to attach itself to the face of every man who has an 
 indicator card handed to him for inspection. As a matter of 
 fact there are a great many people who look at indicator cards 
 in this manner who don't know much more about them than 
 any of you boys do right now. For that reason I intend to 
 tell you something about them, so that you will not altogether 
 belie your looks when you come to do the 'wise' act. 
 
 "An indicator, as its name implies, is used to indicate what 
 
150 MC ANDREW'S FLOATING SCHOOL 
 
 transpires inside the cylinder. You all know that steam 
 enters at one end of the engine and leaves at the other; but 
 it is what it does in the meantime which interests us most. 
 
 "One of the principal features of the indicator is a small 
 steam cylinder, which can be connected directly to either one 
 end of the main cylinder or the other, at will, by simply turning 
 a three-way cock. The steam acting on the piston in this small 
 cylinder is therefore duplicating exactly its effect on the piston 
 of the cylinder to which it is attached at every portion of its 
 stroke. The up and down motion of this small piston is trans- 
 mitted by means of a system of small levers and links to a 
 small pencil point, which is made to move in a straight vertical 
 line. 
 
 "The other main portion of the indicator is the barrel, which 
 by means of a cord attached to a specially arranged reducing 
 gear, is given a rotary motion corresponding on a small scale, 
 of course, to the simultaneous action of the steam engine piston. 
 Then, by pressing this pencil point, moving always in a vertical 
 line, against a piece of paper wrapped around the rotating 
 drum, a figure is drawn, which, to the initiated, shows ex- 
 actly what pressure in pounds per square inch is being ex- 
 erted on the engine piston at every point in its stroke. 
 
 "The little piston works against a spiral spring of a tension 
 designed according to the pressure which is expected to be 
 used in the cylinder. On the high-pressure cylinder we would 
 use springs of from 60 to 100 pounds tension, on the inter- 
 mediate from 20 to 50 pounds, and on the low-pressure a spring 
 of about 10 pounds tension." 
 
 Here McAndrew drew the sketch (Fig. 29) on the black- 
 board, and said, "This represents an ideal indicator card taken 
 from a single-cylinder condensing engine." 
 
 "Huh !" remarked O'Rourke, after the sketch had been com- 
 pleted, "that looks like one of those wooden shoes that 
 Schmidt's grandfather wore." 
 
INDICATOR CARDS AND HORSEPOWER 151 
 
 Schmidt retaliated by remarking that he would bet that 
 O'Rourke's grandfather was a bog-trotter, and didn't have 
 shoes of any kind to wear. 
 
 "That'll do," suggested McAndrew. "This is no lecture on 
 'Shoes of All Nations.' 
 
 "This card is what you would get off a well-designed engine. 
 The line PQ is known as the atmospheric line, or the line 
 
 FIG. 29. INDICATOR CARD 
 
 showing the pressure of the atmosphere. It should always be 
 drawn on the card before making the connection to either end 
 of the cylinder, or otherwise your card will not be of much 
 value. The line RS is known as the line of zero pressure, and 
 has to be drawn on the card with a ruler. As the pressure of 
 the atmosphere is, as I have told you before, 14.7 pounds per 
 square inch, it should be a distance below the atmospheric line 
 equivalent to that pressure on the scale used for whichever 
 tension of spring has been used in the indicator. For example, 
 if a 3O-pound spring has been used, the zero line would be 
 about one-half inch below the atmospheric line and always 
 parallel to it." 
 
 "What's parallel mean?" whispered O'Rourke to Pierce. 
 
 Overhearing the question, McAndrew said, "I am surprised 
 that you don't know the meaning of that term. 'Parallel' 
 means two lines that are the same distance apart at all points, 
 
152 MC ANDREW'S FLOATING SCHOOL 
 
 like railroad tracks, for instance ; they never meet no matter 
 how far they are extended." 
 
 "Schmidt's feet must be parallel, then," interjected 
 O'Rourke. "He' so bow-legged that they have never met yet.'' 
 
 "Now referring to the figure again," McAndrew continued, 
 "you all know that the steam is admitted to the cylinder at 
 the end of each stroke almost instantaneously as the valve 
 opens; this causes the pencil point to go up almost vertically 
 as the revolving drum, following the motion of the engine 
 piston, is then practically at a standstill while changing di- 
 rection. This line AF on the card is known as the admission 
 line ; as the valve remains open the steam continues to rush in 
 at the same pressure, thus making the line AB practically 
 parallel to the atmospheric line. This line AB is known as the 
 steam line. B is the point of cut-off, where steam can no 
 longer enter the cylinder direct from the boilers. The point of 
 cut-off varies from .3 to .7 of the stroke, according to the 
 various conditions. 
 
 "After the valve closes, the steam in the cylinder continues 
 to shove the piston on its travel by the expansive force of the 
 steam. As the piston proceeds on its stroke the pressure of the 
 steam gradually drops, so that the line traced by the pencil 
 assumes a curved shape as shown in the diagram ; this line BD 
 is known as the expansion line. At the point D the valve 
 opens to the exhaust, and the steam rushes out of the cylinder." 
 
 "Do they call it 'exhausted' because the steam is tired out 
 from pushing the piston?" inquired O'Rourke. 
 
 "Very likely that's the reason," smilingly replied McAn- 
 drew. 
 
 "The live steam is now being admitted to the other end of 
 the cylinder driving the piston on its return stroke, and the 
 expanded steam, or 'tired' steam, as O'Rourke thinks it is, 
 continues to escape from the opposite end until suddenly the 
 valve closes at the point E in the stroke, and a certain amount 
 
INDICATOR CARDS AND HORSEPOWER 153 
 
 of this 'tired' steam is imprisoned in the cylinder. As the 
 piston has not yet finished its stroke this portion of the ex- 
 haust steam is compresed in the cylinder, and acts as a spring 
 to overcome the momentum of the piston when it reaches the 
 end of the stroke. It thus acts very much like a bumper on a 
 freight car. At the point F live steam is again admitted to 
 that end of the cylinder, and the operation, which I have out- 
 lined, is repeated. 
 
 "The card which I have shown you is, of course, for only 
 one end of the cylinder ; the card from the other end will be 
 of the same general shape, and the pair will look like Fig. 30" : 
 
 FIG. 30. PAIR OF INDICATOR CARDS 
 
 "That looks like a pair of wooden shoes on a pigeon-toed 
 
 man." 
 
 "What good are all these indicator cards?" inquired Nelson. 
 
 "That's the point I am coming to," replied McAndrew. 
 "They are not of any use unless you can read them intelli- 
 gently. An indicator card to a trained engineer serves about 
 the same purpose as counting the pulse, taking the temperature 
 and looking at the tongue of a sick man does to a physician. 
 You find out what is going on inside. If there is anything 
 wrong with the valves, or if the piston is leaking, it is shown 
 at once on the card. The principal value of a card is, however, 
 to tell how much power is being developed by the engine, and 
 how it is distributed among the cylinders of a multiple-expan- 
 sion engine. 
 
154 MC ANDREWS FLOATING SCHOOL 
 
 "Here are some of the examples of wrong valve setting 
 which can be detected. 
 
 "All eccentrics of a Stephenson link motion valve gear, the 
 one most universally used in marine work, are set at right 
 angles, or one-fourth of the circumference of the crank circle 
 in advance of the crank, plus a small angle known as the 
 angular advance. Now if this angular advance is too large, 
 cut-off occurs too soon, the steam lead, or time the valve is 
 open before the piston reaches the end of the stroke, is too 
 great, and the opening and closing of the exhaust occur too 
 soon ; in other words, all of the functions of the valve are 
 ahead of time, and the result is shown by a card such as I 
 have shown in Fig. 31. 
 
 "If, on the contrary, this angular advance is too small, then 
 all of the functions of the valve are too late, and the resulting 
 card will be like Fig. 32. 
 
 FIG. 31. INDICATOR CARDS, WITH ANGULAR ADVANCE TOO LARGE 
 
 "The steam lap of a valve is, as you have been told before, 
 the amount the valve laps over the steam port when the valve 
 is in its mid-position; the general effect of such a condition 
 is that the cut-off is too soon, the steam opening is late, and as 
 there is not sufficient opening for the entrance of the steam, 
 there is a certain amount of wire-drawing or the effect of 
 passing steam through a contracted opening. This is also in- 
 dicated by a drop in the pressure, which makes the steam line 
 
INDICATOR CARDS AND HORSEPOWER 
 
 155 
 
 get away from its parallel position to the atmospheric line. 
 Such a state of affairs produces a card like Fig. 33. 
 
 "The opposite effect is caused in all the functions of the 
 valve if the steam lap is too small, as shown by a card like 
 Fig. 34- 
 
 FIG. 32. INDICATOR CARD, WITH ANGULAR ADVANCE TOO SMALL 
 
 FIG. 33. INDICATOR CARD, WITH STEAM LAP TOO LARGE 
 
 FIG. 34. INDICATOR CARD, WITH STEAM LAP TOO SMALL 
 
 "In the layout of the valve gear the designer may have 
 made the valve stem too long; this would result in too much 
 steam lap on top and too little exhaust lap on the bottom, 
 which would make the cut-off too early at the top and too 
 late at the bottom, the steam opening on top late and at the 
 bottom too early. Such a contingency would produce a card 
 like Fig. 35." 
 
156 MC ANDREW'S FLOATING SCHOOL 
 
 "That looks as if somebody had given it a swift kick," said 
 O'Rourke. 
 
 "Exactly so," replied McAndrew. "And if the valve stem 
 was too short it would look as if it had received a swift kick 
 at the other end. 
 
 "Now if the piston was leaking badly the result would be 
 very noticeable on the expansion line, as it would not be so full 
 as it is when the piston is tight and the steam is expanded 
 normally. In other words the expansion line would drop below 
 
 FIG. 35. INDICATOR CARD, WITH VALVE STEM TOO LONG OR TOO SHORT 
 
 its right position on the card, showing that the pressure was 
 low on account of the leak. 
 
 "There are many other conditions that are shown by the 
 shape of the indicator cards, most of which can be reasoned 
 out by understanding the general conditions affecting the 
 steam in the cylinder. As your experience in reading indicator 
 cards progresses you will be better able to interpret the con- 
 ditions which exist. 
 
 "We now come to the calculation of horsepower from the 
 indicator diagrams. You will remember that in the early days 
 of this Floating School I tried to impress upon you the mean- 
 ing of power; that is, that it consists of three elements force, 
 in pounds ; distance, in feet ; and time, in minutes. 
 
 "The element of distance is quite easily determined, as 
 knowing the stroke of the engine in inches, we can, by counting 
 the revolutions and multiplying that number by two (as it 
 
INDICATOR CARDS AND HORSEPOWER 
 
 157 
 
 takes two strokes to make a revolution), quite easily deter' 
 mine how far the piston has traveled in any given time. 
 
 "The element of time is readily determined by observations 
 on the engine-room clock or on a watch held in the hand. 
 
 "The third element, of force exerted in pounds, is more 
 difficult to determine, and is the only essential in the calcula- 
 tion which is furnished by means of the indicator card. We 
 know that the steam enters a cylinder at a little less pressure 
 than shown by the boiler gage, and that it leaves at a greatly 
 
 1 4242424241 
 
 reduced pressure. When we have different pressures at every 
 point of the piston's travel, in order to determine the total 
 pressure exerted we must take the average of all the pressures. 
 This is where the indicator card comes into use, as from the 
 scale of the spring used it is possible to determine the pressure 
 exerted at every point of the stroke. To get the average 
 pressure from an indicator card the simplest method is as 
 follows : 
 
 "Divide the card into ten intervals, as shown by y , y-i, etc. 
 Between each of these spaces draw dotted lines just half-way 
 between the full lines. Now add up the lengths of all these 
 ten lines, either by measuring each one separately or trans- 
 
1.58 MC ANDREW'S FLOATING SCHOOL 
 
 ferring them one after another to a strip of paper; divide 
 the total length of all these dotted lines by 10, and the answer, 
 multiplied by the scale of the spring, will give you the average 
 pressure exerted on the piston. 
 
 "Another method is by what is known as a planimeter, a 
 small instrument which usually comes with every set of in- 
 dicators. By this instrument we can ascertain the area of any 
 irregular figure. We can easily measure the length of the 
 card, so by dividing the area in square inches by the length 
 in inches, the quotient will give us the average height, also in 
 inches. This height, multiplied by the scale of the spring, 
 gives the mean or average pressure. 
 
 "Having ascertained the mean pressure per square inch, the 
 next step is to find out the total pressure on the piston. The 
 rule for the area of any circle is to square the diameter; that 
 is, multiply it by itself, and then multiply that quotient by the 
 figures .7854, which gives the area in square inches. Knowing 
 the pressure per square inch and the total number of square 
 inches in the piston, we multiply them together to find the total 
 pressure in pounds on the whole piston, which is, as I told 
 you, the last of the three elements necessary in calculating 
 horsepower." 
 
 "What has 'drawing' got to do with figuring horsepower?" 
 inquired O'Rourke. 
 
 "I don't quite understand you," said McAndrew. 
 
 "A guy out here in the shipyard told me only this morning 
 that all you had to do was to remember the word 'drawing' 
 and you could figure horsepower," argued O'Rourke. 
 
 "Oh! I see what you are driving at. You mean the word 
 P-L-A-N, not drawing. That word has been connected with 
 the subject ever since horsepower was invented. It is a good 
 way to remember the calculation, providing you know what 
 the letters signify. 
 
INDICATOR CARDS AND HORSEPOWER 159 
 
 P means the average pressure per square inch ; L stands for 
 the length of stroke; A is the area of the piston; N is the 
 number of revolutions. 
 
 "It is much better to remember the method, however, by 
 reasoning the matter out in terms of force, distance and time, 
 as I have already told you. We want to get the whole problem 
 into so many foot pounds per minute, then we know that 
 dividing by 33,000 will give us the horsepower. The best way 
 to illustrate the method is to work out a specimen for you. 
 For example: 
 
 "A certain steam cylinder is 41 inches in diameter, the stroke 
 is 36 inches, the mean effective pressure is 42 pounds per 
 square inch, and the number of revolutions is no per minute. 
 What is the horsepower? 
 
 "We find the area of the piston as follows : 
 
 164 
 
 1681 
 7854 
 
 6724 
 8405 
 13448 
 11767 
 
 1320.2574 
 
 "Now multiply the area by the mean effective pressure, 
 1320.25 
 
 42 
 
 264050 
 528100 
 
 55450.50 
 
160 MC ANDREW'S FLOATING SCHOOL 
 
 "This gives us the total pounds pressure exerted on the 
 piston and is the element of force. 
 
 "The distance the piston moves through is, of course, equal 
 to twice the stroke, as the piston has to go up and down to 
 make one revolution, therefore as 36 inches are equal to 3 feet, 
 multiply by 2, and we have 6 feet as the distance moved in one 
 revolution, and in no revolutions it will have moved 660 feet 
 this is the element of distance. 
 
 "The element of time is, of course, one minute, as that is 
 the basis on which horsepower is taken. 
 
 "Now multiply the force (5545O-5 pounds) by the distance 
 (660 feet), and we get 36,597>33O foot pounds per minute. Di- 
 viding this number by 33,000 we find the answer to be 1109 
 horsepower. The calculations I have shown you would be all 
 right if there were no piston rod ; but as that is, of course, a 
 necessity, we must make allowances for the area of the rod, as 
 no pressure is exerted on that portion of the piston occupied by 
 the rod. I should also tell you that in making the calculations 
 the mean effective pressure per square inch must be taken as 
 the average obtained from the top and bottom indicator cards. 
 
 "To allow for the piston rod it is customary to calculate its 
 area the same as for any other circle, and to take only half the 
 area of the rod from the total area of the piston, as the rod is, 
 as you know, on only one side. Thus the area of a piston rod 
 6 inches in diameter is 28.274 square inches. One-half of that 
 is 14.137 square inches. This should be subtracted from the 
 total area of the piston 1320.25, which would leave 1306.11 
 square inches to be multiplied by 42 to obtain the element 
 force, average or total pressure on the piston." 
 
 "Chief, what's the use of all this 'dope' about indicator cards 
 and horsepower to the men that drive the engine?" asked 
 Pierce. 
 
 "I don't suppose that it is very valuable to the ordinary every- 
 day engine-driving man on board ship, but engineers are some- 
 
INDICATOR CARDS AND HORSEPOWER l6l 
 
 what like lawyers in this respect. Every lawyer likes to study 
 about the Constitution and be admitted to practice before the 
 Supreme Court. About one in every hundred ever has oc- 
 casion to use his knowledge in that connection, but he would 
 be a poor lawyer if he didn't aim that high." 
 
CHAPTER XVIII 
 Care and Management of Boilers 
 
 For several weeks there had been an enforced vacation in 
 the Floating School, the reason being that the work of in- 
 stalling the new boilers on the Tuscarora had been rushed 
 night and day in order to get the ship out in time for the heavy 
 trade in the autumn months. The members of the school had 
 been kept so busy that they had but little time for study, and 
 Chief McAndrew, of course, had so much to attend to in the 
 thousand and one details a chief engineer has to think of that 
 he had no opportunity to give the young men any attention. 
 The repair work was finally declared completed ; a dock trial 
 had been held and the new boilers found satisfactory. The 
 ship was to sail early the next morning; O'Rourke and 
 Schmidt had been given two hours' liberty, in which time they 
 had taken a fond farewell of their Fishtown girls. Nelson and 
 Pierce denied that they had any particular sweethearts in 
 Philadelphia, but they had enjoyed their stay in that place so 
 much that they were somewhat loath to leave. 
 
 A full crew had been shipped for the engineer's department, 
 and the Chief had so arranged it that all of his pupils would 
 be in one watch. Much to his gratification, Jim Pierce had 
 been promoted to be an oiler. Gus Schmidt had been given a 
 boost by being signed as a water-tender, which led O'Rourke 
 to remark that it must have been because he was so fond of 
 water. Nelson and O'Rourke were still retained as firemen, 
 but the Chief had promised them that if they paid close at- 
 tention to business they would be given the first vacancies as 
 water-tenders. 
 
 The Chief, of course, having three assistants, stood no watch, 
 and he very kindly agreed to continue his classes at such 
 
CARE AND MANAGEMENT OF BOILERS 163 
 
 intervals while the four aspirants for licenses were "off watch," 
 as it might be convenient for him to spare them a little of his 
 time. 
 
 The ship proceeded down the Delaware River on her way to 
 New York, and as the four young men stood the 8 to 12 watch, 
 McAndrew said he would give them an hour or so of his time 
 that afternoon. The school was quite a mystery to the other 
 men in the engineer's crowd, and some of them were inclined 
 to be a little facetious about the four "high brows," as they 
 termed them. However, as information regarding the school 
 was imparted to them almost simultaneously with an exploita- 
 tion of the fact that O'Rourke had been awarded several prizes 
 as a heavyweight boxer at an East Side resort, the tendency 
 to sarcastic remarks rapidly dwindled. 
 
 On addressing his class that particular afternoon, McAndrew 
 . stated that as the ship was now at sea, and was to continue on 
 her regular duties, he would take up the subject of the care 
 and management of machinery, and naturally would begin at 
 the boilers. 
 
 "Before starting fires under boilers," he said, "we must first 
 examine everything connected with them. See that all stems 
 on the stop valves, check valves and blow valves are oiled, and 
 that the valves can be worked freely. The safety valve gear 
 should be put in good working condition, and the valves raised 
 slightly off their seats. The air cock at the top of the boiler 
 should be opened, or if none such is fitted, open the top gage- 
 cock in order to allow the air to escape. See that the grate- 
 bars are all in place, that the damper works freely, that the 
 handhole and manhole plates are set up tight, that all neces- 
 sary fire tools are on hand, that the bunker doors are opened, 
 and that the surface and bottom blow valves and drain cocks 
 are closed tightly. 
 
 "If steam has not been raised on any of the boilers so as to 
 allow the running of the pumps, the boilers should be filled by 
 
164 MC ANDREW'S FLOATING SCHOOL 
 
 means of a hose from the deck, through the top manhole 
 plates. It is only necessary to fill the boiler up to about two- 
 thirds of a glass, as the water 'swells/ as the term is, when 
 heat is applied to it. That is, in an ordinary boiler the water 
 expands in volume as it is heated until it rises 2 or 3 inches 
 in the glass. If no hot coals from another boiler are available, 
 after throwing some coal on the bars, it is usual to start a 
 wood fire at first and throw on a light covering of coal after 
 the fire has commenced to burn freely. Soft coal catches fire 
 comparatively easily, and so your fires will soon be burning in 
 all the furnaces. In Scotch boilers great care must be taken 
 not to force the fires and raise steam too quickly. It takes 
 a long time to get the heavy shell plates warmed through uni- 
 formly, and if steam is raised too hurriedly the seams will 
 begin to leak on account of the unequal expansion. For that 
 reason it is usual to take from six to twelve hours' time in 
 raising steam. One of the great advantages of watertube 
 boilers is that steam can be raised rapidly without doing them 
 any harm, as from their construction the water is rapidly cir- 
 culated in all parts, and a uniform temperature throughout is 
 easy to maintain. For that reason it is safe to raise steam 
 in the average watertube boilers in a half hour if deemed 
 necessary. 
 
 "The great disadvantage of all Scotch boilers is the large 
 amount of water underneath the furnace which will not cir- 
 culate naturally, and consequently remains quite cool even 
 after steam is formed. To overcome this there are several 
 patented devices which can be fitted to Scotch boilers, which 
 will automatically circulate the dead water under the furnaces 
 until the temperature is raised to very near that of the water 
 above the furnaces. On ships which are not provided with 
 such apparatus it is customary, if steam is available from an- 
 other boiler, to run the auxiliary feed pump slowly, with its 
 suction connected to the bottom blow, and its discharge enter- 
 
CARE AND MANAGEMENT OF BOILERS 16$ 
 
 ing the boiler through the regular feed pipe. This starts up a 
 forced circulation and greatly facilitates the raising of steam. 
 
 "As steam begins to form slowly it will be first indicated by 
 a slight hissing noise of the air escaping through the air-cock 
 or the gage-cock. This air should be allowed to blow until 
 clear steam can be seen escaping. Then the safety valves 
 should be lowered, all cocks closed, and the steam pressure 
 allowed to rise slowly, not over a rate of ten pounds an hour 
 if there is no particular hurry about the operation. When the 
 pressure rises to, say, 100 pounds, the auxiliary stop valve 
 should be opened and steam admitted to the auxiliary line for 
 the purpose of running the various auxiliaries. 
 
 "Having raised the steam to the working pressure, and put 
 the boiler in service, the object of the engineer should be to 
 keep it up to its highest state of efficiency; that is, to get out 
 the most steam for the least expenditure of coal. To do this 
 requires constant care and attention, for, like human beings, 
 boilers respond readily to good treatment and rebel at harsh 
 treatment. There are three principal things to do, which, if 
 attended to Mitelligently, will keep a boiler in good condition. 
 The first of these is to feed it with pure water; second, do 
 not subject it to sudden changes of temperature, and, third, 
 fire it properly. 
 
 "If these three maxims were lived up to there would be but 
 little trouble. Unfortunately, however, they are difficult of 
 accomplishment, and for that reason the average boiler is beset 
 with many ills. Most of these arise from the quality of the 
 water fed to the steel workman. In spite of precautions grease 
 will get in the feed water from the condensed steam; acids 
 will be generated by the contact with the copper condenser 
 tubes and feed pipes, and salt water will get in through leaks 
 in the condenser tubes and pipe connections, and occasionally 
 salt water will have to be fed to make up losses. It is these 
 foreign elements in the feed water which make all the 
 trouble." 
 
i66 MC ANDREW'S FLOATING SCHOOL 
 
 "Yes," broke in O'Rourke, with a meaning glare at Schmidt, 
 "and my father always used to say that it is the foreign ele- 
 ments that make all the trouble in this country." 
 
 "Is that so?" sarcastically replied Schmidt. "I'll bet it 
 wasn't many days before you were born that he was tramping 
 through Castle Garden himself." 
 
 "I don't suppose that any of us is eligible to join the Sons 
 of the American Revolution," said McAndrew ; "but that cuts 
 no figure in this land of the free. 
 
 "As I was saying before being so rudely interrupted, if it 
 were not for the impurities which get into the boilers the 
 engineer would have but little trouble in keeping the interior 
 surfaces clean. To counteract all these impurities is one of the 
 main parts of an engineer's duty. Hence one of the first 
 things to do is to ascertain how much salt water slips in from 
 one source or another. Since steam vessels first plied the 
 oceans, every one has been fitted with an instrument known 
 as a salinometer not 'salometer,' as I have heard O'Rourke 
 term it. This word means literally salt measure, and at that it 
 does not express its use correctly. 
 
 "Salt, of course, is one of the principal solids in salt water, 
 but there are enough other chemicals in it to start a small drug 
 store. In case any one ever asks you what salt water does 
 contain you can refer to this analysis of the average sea water, 
 as it contains the following parts in 1000 : 
 
 Water 964745 
 
 Chloride of sodium (common salt) 27.059 
 
 Chloride of potassium .766 
 
 Chloride of magnesium 3.666 
 
 Bromide of magnesium .029 
 
 Sulphate of magnesia (Epsom salts) 2.296 
 
 Sulphate of lime (plaster of paris) 1.406 
 
 Carbonate of lime (chalk) .033 
 
 1000.00 
 
CARE AND MANAGEMENT OF BOILERS 167 
 
 "Some chemists state that there is also a small quantity of 
 gold in sea water; but I wouldn't advise any of you to buy 
 any stock in a company formed for the purpose of getting gold 
 from that source. 
 
 "Although the instrument I have referred to is called a salt 
 measure, its real purpose is to determine how much solid 
 matter is contained in the water. By adding up the amounts 
 of all the solid ingredients in sea water you will see that they 
 foot up approximately 1/32 of the entire weight of the water. 
 That is, in i pound of salt water there would be 1/32 pound, 
 or y 2 ounce, of solids. Hence all salinometers are graded on 
 that basis; 1/32 means salt water as drawn from the sea; 2/32 
 means twice as much solid contents as ordinary sea water, and 
 so on. 
 
 "With every salinometer there is a small glass instrument 
 weighted with shot known as a hydrometer. This instrument 
 is usually graduated in divisions known as 32nds, which is 
 based upon the principle that a floating body displaces an 
 amount of water equal to its own weight. Hence the heavier 
 or denser the water it floats in, the higher will be the portion 
 out of the water. That is the reason that it is easier for a man 
 to float in salt water than it is in fresh water. I have told 
 you before that water expands when heated, hence its weight 
 or density varies with its temperature. Therefore, to use 
 the hydrometer correctly, the water to be tested must be at 
 the same temperature for which the scale on the hydrometer 
 is adjusted. 
 
 "On most hydrometers there are three scales shown one 
 at 190, one at 200 and the other at 210 degrees F. The method 
 of testing is to open the cock and allow the boiler water to fill 
 a brass vessel, known as the salinometer pot ; if it is below 190 
 degrees F., as shown by the thermometer, admit sufficient hot 
 water from the boiler to heat it up to one of the three tempera- 
 tures shown on the scale. Then put in the hydrometer and 
 
i68 MC ANDREW'S FLOATING SCHOOL 
 
 observe how high it floats on the temperature scale cor- 
 responding to the temperature of the water. If you should 
 hear some one say that the water is 2*4 or 2^2, it would mean 
 2^4 thirty-seconds, or 2^ thirty-seconds, as the case might be. 
 
 "I have devoted some time to telling you about the salino- 
 meter and how to use it, but I will tell you very briefly that it 
 is not of much value nowadays, as that method is too crude 
 for modern usage. You might as well weigh drugs on a hay 
 scale, so far as accuracy is concerned. There is in use on a 
 number of ships a chemical process for determining accurately 
 the amounts of the principal ingredients in boiler water; the 
 apparatus is so simple that if the directions are closely fol- 
 lowed any engineer can use it. 
 
 "Very few marine engineers allow salt water to be used for 
 make-up feed in these days, hence it is not so essential to 
 guard against scale-forming ingredients in the water. The 
 principal causes of deterioration, such as rust and pitting, are 
 due to the acids which get into the boiler water and thus 
 encourage galvanic action." 
 
 "What's that?" blurted out O'Rourke. 
 
 "I thought you wouldn't understand it, O'Rourke, and so I 
 used the term to arouse your curiosity. The word 'galvanic' 
 is derived from the name Galvini, an Italian scientist, who 
 first discovered that an electric current is set up by the action 
 of one metal on another. You all probably know something 
 about the ordinary battery used for generating an electric 
 current. This consists of a glass jar in which are immersed 
 pieces of zinc and copper ; you have probably noticed that the 
 liquid in which they are immersed is slightly blue in color, this 
 being caused by putting in some crystals. The object of these 
 crystals is to form sulphuric acid in which the chemical action 
 between the copper and zinc is readily started, with the result 
 that an electric current is generated ; the further result is that 
 the zinc is gradually eaten away by this action, and after a 
 
CARE AND MANAGEMENT OF BOILERS IOQ 
 
 certain length of time has to be removed. Now if these two 
 metals had been placed in a jar containing pure water there 
 would have been none of this action taking place. 
 
 "Here, then, is the secret of boiler pitting and corrosion ; the 
 whole boiler, if the water is allowed to get in acid condition, 
 becomes like an immense battery, or rather a collection of 
 small batteries, as this action will take place between different 
 parts of the steel of which the boiler is constructed as well as 
 between a brass feed pipe and the boiler shell, only, of course, 
 it will not be so rapid. Hence it is that for years past baskets 
 containing zinc have been suspended in different parts of the 
 boiler immersed in the water, as the zinc is much more easily 
 attacked by galvanic action than are the steel and iron of the 
 boilers. The zinc is therefore eaten away, and theoretically, 
 at least, the various parts of the boilers are spared. Later 
 investigations on the subject have developed the fact that even 
 the use of zinc is not the best step to be taken, as that is simply 
 remedying the effects without removing the cause. In other 
 words, it is similar to trying to cure a headache for a drunken 
 man after every night's jag instead of making him stop drink- 
 ing the booze and preventing the headaches." 
 
 "I can understand that argument all right, all right," said 
 O'Rourke, who had been, for him, paying very close attention 
 to McAndrew's remarks. 
 
 "These later experiments which I refer to have been di- 
 rected towards preventing the boiler water from getting into 
 an acid condition, and thereby stopping galvanic action and 
 rust. It is a well-known law of chemistry that alkalis will 
 counteract or neutralize acids. Plain soda ash, or sal soda, as 
 it is called commercially, is one of the best and cheapest of 
 the alkalis obtainable, hence that is the material best used for 
 counteracting acids in boiler feed water. It is also used to 
 "kill" grease and oils which get into the feed water. Soda 
 and zinc have for many years been relied upon to correct all 
 
17 MC ANDREW'S FLOATING SCHOOL 
 
 of the evils which beset marine boilers, and yet they continue 
 to rust, pit and eat away. 
 
 "By a long and continued series of tests recently held, some 
 curious facts have been learned regarding the use of soda in 
 feed water. One is that a small amount of soda, about one- 
 tenth of i percent, is less corrosive than neutral water, or 
 water that is neither acid nor alkaline ; another is that water 
 above one-tenth of i percent, and up to 2.6 percent alkaline, 
 is really more corrosive in its effect than water in its neutral 
 state. Finally, these experiments demonstrated that water 
 containing 3 percent and over of the alkaline solution is ab- 
 solutely non-corrosive. 
 
 "But the addition of such much ordinary soda to a boiler 
 in which necessarily there are some oils or grease, will in- 
 variably cause violent foaming, or priming, as it is sometimes 
 called. This is prevented by mixing with the soda certain 
 proportions of glucose and a substance known as 'cutch/ 
 which is a form of tannic acid. These ingredients tend to pre- 
 vent foaming and the formation of scale. These materials are 
 combined in standard makes of boiler compounds, and if they 
 are properly used there is little doubt but that pitting and 
 rusting will cease to a great extent. In order to get a 3 percent 
 solution of the boiler water it is necessary to add about $ 1 A 
 pounds of this compound for each ton of water in the boiler. 
 
 "Heretofore the care of boilers has been very much on the 
 order of quackery in dosing the human system with all kinds 
 of patent nostrums. There are but few medicines given by 
 doctors which really accomplish any good, and they have been 
 developed by experimenting. Many a good man has lost his 
 life by having various kinds of 'dope' tried out in his stomach, 
 and many a good boiler has met an untimely end by ignorant 
 treatment. Now the 'boiler doctors' are really studying the 
 subject, and from this time on boilers will be given better 
 treatment. You young men are coming into the business at a 
 
CARE AND MANAGEMENT OF BOILERS 
 
 171 
 
 time when the new methods of treating boilers are being 
 perfected, and I predict that by the time you get in charge of 
 steam machinery you will know much better how to take care 
 of your boilers than engineers have in the past. 
 
 "No matter how well you treat the boilers while running 
 they must, at certain periods, be given an overhauling, and at 
 such times the greatest care and attention must be given them. 
 
 "The fire surfaces must be thoroughly cleaned and all de- 
 posits of soot brushed off. The water surfaces must be given 
 the closest attention, and particular care taken to clean all 
 dirt and scale off the crown sheets or tops of the furnaces. As 
 you all know, this is no easy job, especially with Scotch 
 boilers, as the spaces in which a man has to work are neces- 
 sarily cramped, the air he breathes is vile, and there is every 
 condition which would make him shirk the work, yet if the 
 cleaning and scaling are not done properly the boiler and the 
 coal pile will suffer alike. 
 
 "To give you an idea of the bad effect of even a slight 
 amount of scale on the heating surfaces of a boiler, you will 
 be surprised, I know, to learn that a hard scale only one- 
 twentieth of an inch thick reduces the efficiency of a boiler 
 1 1. 1 percent. That is, if a boiler is scaled up to that thickness 
 on its heating surfaces, for every hundred tons of coal con- 
 sumed there will be an absolute loss of n.i tons in the steam- 
 producing effect." 
 
 "That would very nearly pay the fireman's wages, wouldn't 
 it?" inquired Nelson. 
 
 "Yes, and more than pay them, so you can see the neces- 
 sity for keeping boilers clean. 
 
 "Soot on the fire surfaces has almost as bad an effect, so 
 you can understand how important it is to blow the tubes 
 while running." 
 
 "The company ought to pay us extra every time we blow 
 tubes," suggested O'Rourke. 
 
172 MC ANDREW S FLOATING SCHOOL 
 
 "That's where you are wrong, as usual, O'Rourke. Em- 
 ployers in these days pay people to look after their interests 
 in every way, and because a man is a .fireman doesn't mean that 
 he is for the sole purpose of shoveling coal in the furnaces. It 
 is the fellow who thinks what he can do to save his employers 
 money by keeping the particular piece of machinery which 
 he is handling up to the highest state of efficiency who gets 
 promoted and carries away the most coin on pay day. 
 
 "When cleaning boilers it is very important that all the 
 valves and attachments be given a thorough inspection and put 
 in first-class condition. All screw valve stems should be oiled 
 with cylinder oil and graphite, glands repacked, safety valve 
 lifting gear oiled and made to work easily. Small pin-head 
 leaks should be touched up with a calking tool as soon as they 
 are noticed. A leak in a boiler should be treated in accord- 
 ance with the old saying, 'A stitch in time saves nine.' 
 
 "Many people have the idea that a fireman to be successful 
 need only be sufficiently strong to stand the heat and shovel 
 coal in the furnace for a period of four hours at a time. That 
 is a great mistake, as the successful operation of marine ma- 
 chinery depends more upon skillful firing than upon any other 
 part of the business. No man can be a successful marine engi- 
 neer unless he knows how coal can be burned most efficiently, 
 and sees to it that what he knows in that line is put into force 
 by the gang in the fire-room. The average fireman if left alone 
 to follow his inclination will nearly always fill up his furnaces 
 to the top, under the mistaken idea that a 'crown-sheeter,' as 
 it is termed, makes the most steam. The average fire-room 
 watch will, if 'not instructed otherwise, as soon as they come 
 on duty clean their quota of fires, usually about one of every 
 three, fill up the furnaces, then sit down and smoke for an 
 hour or so. The boilers will also smoke under such treatment 
 and make about as little steam as possible. 
 
CARE AND MANAGEMENT OF BOILERS 173 
 
 "In order to get the best results the following rules should 
 be stuck to closely : 
 
 "Carry the fires for natural draft not over 8 or 10 inches 
 thick ; if forced draft is used they should be about a foot thick. 
 
 "Put on only two or three shovelfulls at a time in each 
 furnace throw it on quickly and spread it evenly over the fire. 
 
 "Never open more than one furnace door at a time, and 
 close it just as soon as possible. 
 
 "Never throw in any lumps larger than a man's fist; have 
 the coal passer exercise himself by using a coal maul on larger 
 lumps before putting the coal in the furnace. 
 
 "Only use a slice bar to remove clinkers or ashes, and to 
 keep the fires bright from the under side. 
 
 "Keep the ash pans clear at all times. 
 
 "Clean only one fire at a time, and so regulate the periods 
 between cleanings that they come regularly, if the coal is of 
 uniform quality; otherwise clean them whenever they get 
 dirty. 
 
 "If the draft is strong and the coal very fine and dusty, 
 sprinkle a little water on the coal. 
 
 "Keep the fires of even thickness by the use of the hoe or 
 rake ; level them off every other time that coal is thrown into 
 the furnaces. 
 
 "Have each watch get out its ashes before being relieved, 
 otherwise there will be a scrap with the next watch. 
 
 "In general, have everything done in the fire-room with 
 some snap." 
 
 "In other words," butted in O'Rourke, "put some ginger into 
 the work." 
 
 "Yes, that's it ; let the 'ginger-snap' be the motto of the fire- 
 room." 
 
 "It's more likely to be the hardtack," suggested the Hiber- 
 nian. 
 
174 MC ANDREW S FLOATING SCHOOL 
 
 "That's true, too, unless you use your brains as well as your 
 muscles." 
 
 "Won't you tell us something about a water-tender's duties?" 
 asked Pierce, who was feeling the responsibility of his new 
 job. 
 
 "I was just coming to that," replied McAndrew. "The suc- 
 cess of the fire-room depends largely upon the water-tender ; 
 the engineer of the watch may issue all the instructions about 
 firing that he wants to, but he can't be in the fireroom all the 
 time to see that they are carried out. Hence a rattling good 
 water-tender is very necessary. Primarily he wants to be a 
 man of nerve, quick to think and quick to act, and it's not a 
 bad asset for him to be able to lick any fireman or coal-passer 
 in his watch. Not that he should resort to tactics of that 
 kind far be it from me to suggest any such cruel procedure 
 but I have noticed in my several years of climbing that a 
 water-tender who is handy with his fists generally keeps the 
 ginger in the ginger-snap with his men. His principal job is to 
 keep his mind on his duties during every minute he is on 
 watch, and to keep his eye on the gage-glasses at least once 
 every minute. 
 
 "He must also see that the furnaces are charged regularly 
 in accordance with his instructions ; that the fire-room is kept 
 clean; that the coal is tallied; that the ash pans are hauled 
 and the ashes blown out, and, in general, that all the routine 
 duties of the fire-room are kept up. Ordinarily he should see 
 that the water is maintained at about half a glass, and that the 
 feed is so regulated by the check valves that it remains steady 
 at that height if possible. As long as a boiler is under steam 
 and the engines running, the feed should never be entirely cut 
 off no boiler has ever yet been blown up by having too 
 much water in it, so there is no danger to the boiler even if 
 you do put too much water in it sometimes there is danger 
 to the engine on account of foaming, caused by too much 
 
CARE AND MANAGEMENT OF BOILERS 175. 
 
 water. In general, the all-important thing to guard against in 
 tending water is that there will always be water showing in 
 the gage-glasses. Low water is the cause of 90 percent of all 
 boiler explosions, and in nearly every case it is a direct result 
 of carelessness. 
 
 "In case the water does get out of sight, as it will do at 
 times in the best regulated fire-rooms, the first thing not to 
 do is to get excited. No boiler ever has blown up immediately 
 after the water has dropped out of sight. Keep cool yourself 
 and try to cool the affected boiler. If you feel positive that 
 the water level is only a little below the bottom of the glass, 
 open the check valve wide and hold your breath. You may, 
 during your first experience, think that it is taking about one 
 month and ten days for the water to show up, but in reality it 
 is usually visible in four or five minutes; then you can begin to 
 breathe again. If, however, the water is out of sight, and you 
 don't feel positive of the last time you saw it, close the 
 damper ; put up the ash-pit doors ; shut off the main and 
 auxiliary stop valves and the check valve and throw wet ashes 
 or fresh coal over the fires to deaden them. Never haul the 
 fires out until they have been deadened or extinguished by 
 water, as stirring them up temporarily causes an increased heat, 
 which might prove disastrous. 
 
 In case of low water, the first thing, of course, is to try and 
 remedy it by cutting out the boiler affected, as above de- 
 scribed. But the water-tender must remember that the other 
 boilers are still steaming, and he must not neglect to see that 
 they are properly looked after, notwithstanding the temporary 
 excitement on account of the crippled boiler. To sum it all 
 up, a good water-tender must combine attention to business, 
 quickness to act, and imperturbability of the highest degree." 
 
 This last qualification simply stunned O'Rourke, and while 
 he was trying to recover from the shock the length of the 
 word had given him, the Chief said : "I knew that would hold 
 
176 MC ANDREW'S FLOATING SCHOOL 
 
 you, O'Rourke; but don't be alarmed, it simply means the 
 quality of not getting rattled ; you have your share of it. 
 
 "When the ship arrives in port and the boilers are to be 
 out of use for several days, the fires should not be hauled, but 
 simply allowed to die out gradually, so that there will be no 
 sudden cooling of the boiler shell. It is usually advisable to give 
 them a good blowing off from both the bottom and surface 
 blows. After the steam is gone they should be pumped up full 
 with fresh water, putting on a small pressure of 5 or 10 pounds 
 to make sure that they are filled up. They should never be 
 emptied by blowing off, as that causes too sudden cooling. If 
 the boiler is to be cleaned the fires should be allowed to die 
 out and the water pumped out after the steam has disappeared. 
 
 "If the boiler is to stand full of water for any length of 
 time, the water should be made alkaline, so as to prevent cor- 
 rosion as far as possible. 
 
 "If the ship is to be laid up great care should be paid to 
 putting the boilers in such condition that they will not de- 
 teriorate. The grate-bars and furnace fittings, ash pans, etc., 
 should be taken out and stacked up in the fire-room, out of 
 the way but in a convenient position to be replaced. The in- 
 terior of the furnaces, the combustion chambers and the tubes 
 should be thoroughly brushed and cleaned to remove all soot 
 and ashes. They should then be given a coating of black oil 
 all over. The inside or water surfaces should be thoroughly 
 cleaned and then thoroughly dried out by starting a light wood 
 fire in the furnaces for a few moments, and by burning pans 
 of charcoal inside the boiler. Some people prefer to fill the 
 boilers up solid with water when they are to be laid up for 
 several months, but I prefer to have them laid up dry as I have 
 described. All the valves should be overhauled; put in good 
 condition, and the valve stems coated with heavy oil or grease. 
 A hood should be placed over the smokestack in order to keep 
 the rain from leaking down and running into the up-takes. 
 
CARE AND MANAGEMENT OF BOILERS 177 
 
 "I could tell you lots more about the care of boilers, as you 
 must remember that it is almost an inexhaustible subject. 
 However, I have touched on the high spots of care and man- 
 agement, and you must learn much more by reading and from 
 experience, the greatest teacher of all." 
 
 "They say old Experience is a hard teacher," suggested 
 O'Rourke. 
 
 "You will find that he is if you don't follow the rules of 
 his school." 
 
 "What are they?" 
 
 "His schools on board ship require diligence, energy and 
 sobriety; if those three are lived up to you will find the old 
 fellow is rather an easy teacher." 
 
CHAPTER XIX 
 
 Care and Management of Engines and 
 Auxiliaries 
 
 The Tuscarora arrived in New York and was loaded for 
 her first trip South after the extensive repairs she had under- 
 gone. The chief had, of course, been so busy attending to 
 getting the vessel's stores, etc., ready for her regular trips 
 fliat he had paid .no attention to his class other than to 
 caution them to keep on with their studies and to learn as 
 much as they could from observation, keeping in mind what 
 he had told them about the various parts of the machinery. 
 
 There was a new second assistant by the name of Davis on 
 board, and he had been placed in charge of the boilers. Coming 
 into the fire-room suddenly one day he found O'Rourke de- 
 livering a lecture to a couple of coal passers on how steam 
 was generated. "This blatant heat," he was saying, "is what 
 makes you fellows hustle out the coal ; it's like shoveling snow 
 in the East River to make the tide rise ; you don't seem to get 
 a run for your money until all of a sudden 'biffo,' the steam 
 shows on the gage !" 
 
 Davis could stand it no longer, and said, "Cut that out, 
 O'Rourke, and get down to work what do you know about 
 steam, anyhow?" This highly incensed the shining light of 
 the Floating School, and he replied rather impudently that he 
 "was only trying to give these ginks a little scientfic dope." 
 Later in the day O'Rourke complained to the chief that the 
 second assistant had cut short his efforts at enlightening the 
 coal passers on matters he had learned at the school, but he 
 was told to pay more attention to his work and not to bother 
 
CARE AND MANAGEMENT OF ENGINES 179 
 
 with imparting his knowledge to an unappreciative audience. 
 
 The ship sailed from New York at her scheduled time, and 
 was soon bucking into a southeaster as she headed down the 
 coast. It cleared off the next day, and as everything was 
 working smoothly the chief rounded up his class that after- 
 noon, all of them being off watch, and proceeded to give them 
 some further instruction. 
 
 He began his remarks by saying that it was a most unusual 
 thing for a chief engineer of a vessel to take time while his 
 vessel was underway to be holding a school for his men, but 
 as he had only a little further to go in his remarks he was 
 determined to finish the job up, even if he did have to defy 
 all precedents. 
 
 "Having told you something about the care and manage- 
 ment of boilers, I propose this afternoon to give you some 
 hints on the care and management of the main engine and the 
 various auxiliaries in the engine room. 
 
 "An engineer standing a watch at sea has so many things to 
 attend to that to enumerate them all would fill a book in itself. 
 Probably no other business requires so much alertness and 
 quick acting and thinking as a marine engineer is called upon 
 to do in the proper performance of his duties. Every faculty 
 which God has given him is called into use. Unlike locomo- 
 tive and stationary engineers, he must never allow his engines 
 to stop for days and days at a stretch. A locomotive will be 
 driven for five or six hours and then run into a roundhouse 
 for a rest; a stationary engine will be run for ten or twelve 
 hours and then stopped; but it is very seldom that a marine 
 engine is ever stopped or even slowed down in a voyage last- 
 ing very often a week, or even two weeks at a time. To do 
 this successfully requires the highest degree of skill, and above 
 all things the closest attention to even the most minute de- 
 tails, as the derangement of even a very small part of an 
 engine often results in a serious breakdown at a critical 
 
i8o MC ANDREW'S FLOATING SCHOOL 
 
 moment. Remember, young men, that to be successful in your 
 business as an engineer there is no detail about the entire 
 mechanism of a ship that is too trivial to demand your 
 closest attention. 
 
 "Preparations for getting underway for a long trip at sea 
 should begin early in the morning of sailing day. If repairs 
 or adjustments have been made during the stay in port, the 
 engineer should personally see that every set-screw on the 
 moving parts is set up tight; that all the bearings have been 
 oiled around by hand; that all oil cups are filled; that the 
 sight-feeds are properly adjusted and in working condition. 
 To make sure that all parts of the main engine are clear, it 
 is well to turn the engine at least once clear around, either 
 by hand or with the jacking engine. After this is done he 
 should personally see that the worm of the turning gear is 
 thrown out of gear; failure to do this has cost many a man 
 his job. 
 
 "The first thing to do is to start the circulating pump slowly 
 and get the condenser cooled off and ready for the exhaust 
 steam. An hour or more before time to start, depending upon 
 the size of the engine, steam should be admitted slowly to the 
 steam jackets around the cylinders, if there are any, if not 
 steam can be let into the cylinders direct by cracking the 
 throttle slightly and opening the by-pass valves. All drain 
 valves from cylinders and valve chests must be kept open to 
 the condenser, as steam striking the cold cylinder walls is 
 immediately turned into water, and should be allowed to drain 
 into the condenser. 
 
 "The warming up of large iron castings must be done slowly 
 and thoroughly never make haste in this process unless in a 
 great emergency. After the cylinders are too hot to bear your 
 hand on them, and having ascertained from the people on 
 deck that sufficient mooring lines are out, steam may be ad- 
 mitted to the engine very slowly at first, and the turns gradu- 
 
CARE AND MANAGEMENT OF ENGINES l8l 
 
 ally increased to not more than half-speed. The reversing 
 engine should be tried back and forth a number of times to 
 see that it works satisfactorily, and to see that the main 
 engine will run well in the backing gear. The water service 
 should be started. The drain valves should be kept partly 
 open all the time that the engine is being warmed up, and, in 
 fact, they should not be closed altogether until the vessel is 
 underway from the dock for at least ten or fifteen minutes. 
 
 "Before sailing the chief engineer has, of course, satisfied 
 himself that all necessary stores are on board; that the oil 
 tanks are rilled up, and that all wrenches and other tools for 
 making quick repairs or adjustments are in place and easy of 
 access. 
 
 "Everything now being ready, and the captain advised of 
 that fact, the engineer stands by the throttle, posts a man at 
 the engine-room telegraph, which has been previously tried 
 and found to work satisfactorily, and awaits the starting 
 signal. All signals from deck must be answered promptly, as 
 in working away from the dock and through the crowded 
 harbor any delay whatsoever in quickly working the engine as 
 directed would be dangerous. Full speed is seldom ordered 
 until the vessel is well clear of the harbor, but when it is 
 rung up the throttle should be opened only to such an extent 
 that the engine will just use up all the steam that the boilers 
 will make, and will maintain a uniform number of revolutions. 
 Fluctuations of the steam pressure should be avoided as much 
 as possible, and so far as he is able the engineer on duty 
 should strive to carry uniform boiler pressure, revolutions 
 and vacuum. 
 
 "The first few hours of a run the man on watch should be 
 unusually alert in feeling bearings, especially those which may 
 have been recently adjusted, in order to detect the first sign 
 of unusual heat. When a bearing starts to warm up it gets 
 'red hot,' as the saying is, in very short order, and should be 
 
182 MC ANDREW'S FLOATING SCHOOL 
 
 given instant attention. The causes of hot bearings are in 
 most cases due to being set up too tight or else from insuf- 
 ficient oil supply. Occasionally heating is due to the presence 
 of grit, but that can only result from rank carelessness in not 
 having the bearings sufficiently covered up or otherwise pro- 
 tected when the engine is not in use." 
 
 "How do you cool a hot journal without stopping the 
 engine?" inquired Nelson. 
 
 "Put cold water on her, of course, the same as you would 
 cure a headache," volunteered O'Rourke. 
 
 "That's the very last thing you should do," continued the 
 chief. "The first thing is to give it a large dose of oil, and 
 in nine cases out of ten you will find that it will gradually 
 cool off from that treatment. If it persists in heating up after 
 yon are sure that it is getting plenty of oil get out the proper 
 wrenches and slack off the nuts a trifle. This generally ac- 
 complishes the object sought, but if even that method fails 
 then resort to the water service, as sparingly as possible, but 
 just enough to keep down the heat. If the ship was running 
 in fresh water the effect would not be so bad, but salt water 
 on a bright journal is harmful." 
 
 "I get you, chief," broke in the effervescing O'Rourke. 
 "Curing a hot bearing is just like curing a man of a stomach 
 ache. If it isn't very bad give him a dose of castor oil; if 
 it gets worse put on a mustard plaster ; if that don't work give 
 him an injection of fresh water, not salt, as that would hurt 
 him." 
 
 "Your powers of comparison are certainly well developed, 
 O'Rourke, but I fail to see the similarity between slackening 
 up a bearing and putting on a mustard plaster." 
 
 "Well, if that mustard plaster attends to its business all 
 right the man will want to slack it up, you can bet." 
 
 "Chief, will you please give us some points on oiling," sug- 
 gested Pierce, who was feeling the responsibility of his new 
 job. 
 
CARE AND MANAGEMENT OF ENGINES 183 
 
 "I was just coming to that important subject," replied the 
 instructor. "Oiling, like water tending, is a very important 
 job on board ship. Although people refer in a slurring man- 
 ner to the 'greasers' there are few jobs anywhere which have 
 the importance of a marine oiler. A little inattention to his 
 duties may result in doing great damage to the machinery, 
 and may even stop or cripple the ship. An oiler in his rounds 
 must be as regular as clock work, and constantly on the alert 
 with his senses of feeling, hearing, seeing and even smelling. 
 To a trained oiler all these senses come into play. By feeling 
 of revolving crankpins, eccentric straps, main journals, etc., 
 with his hands he can tell instantly if any of them are over- 
 heated, or even if they show a tendency to heat To his sensi- 
 tive ear the first discordant noise, even the slightest squeak, 
 will indicate that some bearing or journal is running dry and 
 needs immediate attention. His eyes must be sufficiently keen 
 of vision to see minute and almost invisible drops of oil pass- 
 ing down the tubes of automatic oilers, and at times to dis- 
 cern even the slightest sign of smoke, which would indicate 
 an overheated bearing. His sense of smell is called into play 
 to detect the first indication of overheated oil or grease." 
 
 "What about his sense of humor," inquired Schmidt. 
 
 "Every oiler must have that sense well developed also, as 
 his main object is to prevent any squeaks or groans from the 
 bearings under his charge. 
 
 "In giving advice to you on oiling I want first to warn you 
 against putting too much dependence on automatic oiling gear 
 of any kind. Such apparatus is all right when it" works well, 
 and I must say that it does work well for 99 percent of the 
 time ; but there is always that small percentage of the time 
 when it does not work well that you must guard against. A 
 change in the temperature of the air surrounding a needle 
 valve on oil reservoirs will often change the adjustment of 
 the drip, so that the bearing to which it directs the flow of oil 
 
184 MC ANDREW'S FLOATING SCHOOL 
 
 will not receive a sufficient quantity and become heated. The 
 same trouble might be started by a small speck of dirt or grit 
 getting under the valve. Therefore these contrivances must 
 be given very close attention. 
 
 "Many engineers prefer the old-fashioned wick feeds, as 
 they are much more positive in their action, although not quite 
 so easily adjusted. 
 
 "Most oilers, and especially beginners, use entirely too 
 much oil, both from oiling by hand and from the automatic 
 feeds. However, this tendency is quite easily regulated by the 
 system of putting every man on an allowance for his watch. 
 The good oiler usually finds his allowance to be ample, 
 whereas the negligent man and the inexperienced man have to 
 hustle to keep things running cool on the amount given them. 
 
 "A routine should be established, the time between oilings 
 being regulated to suit the speed of the engine and the neces- 
 sity for the oil. Usually crankpins and eccentric straps should 
 be oiled by hand once each twenty minutes; the main journals, 
 link gear, etc., once each half hour. An. inspection of the 
 thrust bearing, spring bearings and. stern tube gland once each 
 half hour is usually sufficient. Piston rods and valve stems 
 should be swabbed every half hour, but as little oil as possible 
 should be used each time, as it is by this means that oil gets 
 inside the cylinders, is carried into the condenser and then 
 pumped into the boilers. This is an evil that must be guarded 
 against as much as possible. 
 
 "On many modern ships no oil whatever is used to lubricate 
 the main engine pistons and valves ; if any lubricant is neces- 
 sary many engineers use graphite mixed with water. As a 
 matter of fact in engines using piston valves, internal lubrica- 
 tion is not absolutely necessary. The cylinder walls are 
 always at a less temperature than the entering steam; conse- 
 quently some of the steam is condensed, and the water formed 
 by this condensation acts as a lubricant. 
 
CARE AND MANAGEMENT OF ENGINES 185 
 
 "On the smaller engines, used as auxiliaries, such as pumps, 
 blowers and dynamos, internal lubrication seems to be more 
 of a necessity, and it is by this means that oil gets into the 
 feed water and later into the boilers. The introduction of the 
 steam turbine for driving dynamos and pumps does away 
 with this danger, as, of course, no oil is necessary for the in- 
 terior of turbines. 
 
 "Many engineers prefer to use grease, or compound, as it 
 is termed, on small journals, and on those which have but 
 little friction. Cups, known as compression cups, are screwed 
 to the caps of such journals, and the oiler, by simply giving a 
 small twist to the screw top on the cup, forces enough grease 
 on the journal to last sometimes for several hours. Some 
 engineers use grease for thrust bearings and tunnel bear- 
 ings, but it is more economical to use oil. On well-designed 
 thrusts the collars on the shafts are made to run in a bath 
 of oil, which is kept cool by salt water circulated through coils 
 in the bottom of the bearing. 
 
 "Oil should be caught in the drip-pans and passed through 
 oil filters, of which there are several good types on the 
 market, after which it can be used over again. 
 
 "It takes experience to make a good oiler, but, of course, 
 you cannot get the experience without actually doing the 
 oiling. In your first attempts you will do well if you only 
 take the bark off your knuckles, and perhaps lose a finger nail, 
 while feeling the crankpins and eccentric straps. This is a 
 very important part of his duties and can be learned only t)y 
 practice. One good rule to remember is never to feel a 
 rapidly-revolving piece of machinery that is running toward 
 you ; wait until it starts to go away from you and then feel 
 it very* quickly. No day-dreamer can be successful, as feeling 
 of crankpins, etc., requires quick action. Wherever it is prac- 
 ticable on fixed bearings use the backs of your fingers to feel 
 with, as they are more sensitive to heat than the hardened 
 working surfaces of a man's hand." 
 
i86 MC ANDREW'S FLOATING SCHOOL 
 
 "Schmidt ought to use that nose of his, as they say he is 
 very sensitive about the length of it," suggested O'Rourke, 
 who, for him, had been silent for a long time. 
 
 Schmidt retaliated by saying that it would never do for 
 O'Rourke to use his cheek for feeling journals, as the metal 
 would have to be red hot for him to even notice it by that 
 method. 
 
 McAndrew called them both down hard for making such 
 personal references, and said that oilers were supposed to be 
 courteous to one another. If they are not there might be all 
 kinds of trouble when relieving one another as the watches 
 changed. "The man about to be relieved," said he, "must 
 have all his oil reservoirs filled up and all the bearings and 
 journals under his care running cool, or otherwise the oiler 
 coming on watch could refuse to relieve him. 
 
 "I hope," he continued, "that O'Rourke and Schmidt never 
 have to relieve one another from oilers' watches, as I am 
 afraid they would both be standing double watches the 
 greater part of the time." 
 
 "Chief, won't you put us onto some of the duties an engi- 
 neer has to do in port?" suggested Schmidt, who was prob- 
 ably the most eager for knowledge of any in the class. 
 
 "Certainly," replied the general instructor. "The first thing 
 most of them do is to beat it for their own homes, or some- 
 one else's home, according to circumstances. Of course, that 
 is natural, as a man who stands engine-room watches for a 
 week or more at a stretch, is mighty glad to hit the beach 
 and stretch himself out in a four-poster at least one night 
 in ten; but, seriously speaking, there are many important 
 things which the engineer's gang must do before sailing day 
 arrives again. Nowadays any repairs involving machine work 
 of any description is put into the shops, as the engineer's 
 force usually has neither time nor the necessary tools for 
 making any very extensive repairs. The work most usually 
 
CARE AND MANAGEMENT OF ENGINES 187 
 
 performed in port might be divided up under four headings. 
 Cleaning is one of the first things to perform; adjustment of 
 bearings must be attended to; making new joints and pack- 
 ing of stuffing-boxes must be performed, and examinations of 
 the interiors of cylinders and the auxiliaries must be made 
 periodically. These four divisions of work probably constitute 
 nine-tenths of the duties performed in port. 
 
 "As soon as the jingle-bell is rung, signifying 'through with 
 the engine/ the boys should be set to wiping the engine down 
 and cleaning up the floor plates. Some engineers like to have 
 a small injector so fitted and connected up that it can be used 
 to wash down the bed-plates and bilges with hot water; but 
 I don't believe in squirting salt water indiscriminately about 
 an engine room, as it is bad for the bearings and bright work. 
 Gaskets, made of hemp, loosely laid up, should be laid across 
 both ends of all the principal journals to keep out any dirt 
 or grit which might be around while the engine is not in use. 
 During the stay in port, bulkheads should be scrubbed if they 
 have become dirty, storerooms cleaned out and put in good 
 order, bilge strainers cleaned thoroughly, the bilges themselves 
 cleaned and kept well painted, the filtering material renewed 
 in the feed tank, and in a general way the whole department 
 given such cleaning, painting and renovating as cannot well 
 be done while the machinery is running. 
 
 'The adjustment of bearings is probably one of the most 
 important duties for the engineer and his assistant. If a 
 bearing runs a little slack and develops a slight pound it 
 should be carefully readjusted, or if there has been a tendency 
 for any particular bearing to heat up during the trip it should 
 be examined, and if necessary overhauled and readjusted 
 while the ship is at the dock." 
 
 "Why are they always monkeying with the crankpins on this 
 ship?" asked O'Rourke. "It seems to me," he continued, 
 "that that is all one of the assistants does while this ship is 
 
I??- MC ANDREW'S FLOATING SCHOOL 
 
 at the dock. I see him running around with something that 
 looks like a handful of spaghetti, and he is always saying 
 that he has got her down to 29, or some number like that. 
 You'd think he was running a keno game. Ke ought to " 
 
 "Well, O'Rourke," interrupted the chief, "if you're running 
 this talkfest I'll quit and let you take the chair." 
 
 "I'm through," meekly replied the Hibernian, realizing, for 
 once at least, that he was sat upon. 
 
 ''Bearings lined with white metal are now almost uni- 
 versally used," said McAndrew, after re-establishing himself 
 as boss of the school room. "These wear down considerably 
 during long-continued runs, and consequently must be ad- 
 justed more often than the old-fashioned bearings of solid 
 brass. In the early days it was the test of a good engineer 
 to make adjustments by chipping and filing down the edges of 
 the brasses uniformly, as that was the method then in vogue. 
 All bearings in these times have pieces of brass, known as 
 distance pieces, between the upper and lower brasses; when 
 the wear has been excessive these distance pieces can be 
 planed down in a shaper very quickly. However, that is sel- 
 dom necessary, as liners, or shims, consisting of varying 
 thicknesses of sheet brass, are also fitted between the distance 
 pieces and the brasses. By removing one of the thinnest 
 liners a very small lost motion can be- taken up and the 
 tendency of the bearing to pound prevented. Of course, it is 
 necessary to have some slight clearance to all bearings, else 
 it would be difficult to distribute the oil over the rubbing sur- 
 faces. A good rule to remember for the amount of the clear- 
 ance is that for every inch of diameter of a bearing there 
 should be two one-thousandths of an inch of space. Thus for 
 a 12-inch crankpin the clearance should be 12 X .002 .024 
 inch. This corresponds practically to No. 24 B. W. G., which 
 is a safe clearance space. Some engineers would set them 
 up tighter than that, but when they do there is always a good 
 
CARE AND MANAGEMENT OF ENGINES 189 
 
 chance for them to heat. By the same rule a 6-inch diameter 
 crosshead pin should have .013 inch clearance, which cor- 
 responds to No. 30 B. W. G." 
 
 "What's that mean, chief?" asked Pierce. 
 "B. W. G. means 'Birmingham Wire Gage.' Wire, you 
 know, is made of a great many different diameters, and in- 
 stead of expressing them as so many thousandths of an inch, 
 it is much simpler to say No. i, 7 or 27, or whatever it hap- 
 pens to be. Birmingham in England is one of the leading 
 wire manufacturing communities, so the gage most generally 
 used is the one which was adopted at that place many years 
 ago. 
 
 "In adjusting a bearing, as, for example, the main bearings 
 of the engine, the cap or top part should be removed by means 
 of a chain hoist, and the white metal and oil grooves ex- 
 amined. If it is found that the brass does not bear well on the 
 shaft journal it must be scraped down to a good fit. To do 
 this properly the journal should be smeared over with a thin 
 coating of red lead and oil and the cap put back in place. 
 Where the white metal of the brass touches the shaft there 
 will be red spots. These spots should all be carefully scraped 
 down and the cap again tried as before. A^ter this is repeated 
 several times, the brass should be found to bear on the 
 journal quite uniformly. Always remember that the principal 
 bearing should be in the center of the brass. The outside 
 edges should not touch at all, for if they bear on the journal 
 when it is cold it will be found when the temperature of the 
 bearing rises to a working heat there will be a tendency for 
 the edges to squeeze in on the shaft; or nip, as it is termed, 
 which will cause the bearing to become overheated. It is also 
 necessary to fit them in this way to provide for wear, the 
 heaviest of which is naturally in the center of the brass. After 
 the bearing is found to be satisfactory, so far as its surface is 
 concerned, the oil grooves should be carefully cleaned out, and 
 
190 MC ANDREW'S FLOATING SCHOOL 
 
 enlarged where necessary, as it is of vital importance to have 
 the grooves amply large and so placed that a uniform dis- 
 tribution of the oil will take place. 
 
 "For final adjustments three strips of lead wire about 1/16 
 inch in diameter should be laid across each journal, one at 
 each end and one in the middle. The cap should then be 
 replaced, and the main bearing nuts set down as tightly as 
 possible by means of a box-wrench and a sledge. The posi- 
 tion of the nut in reference to the end of the bolt should be 
 marked with a scriber, so that you will know how tight to 
 set up on the nuts after the cap has again been taken off and 
 the three pieces of lead wire removed. The leads, as they are 
 called, should be measured by means of the wire gage, to see 
 that they are of about the thickness necessary for the desired 
 amount of clearance. A more accurate method for determin- 
 ing the amount of clearance from the leads is by means of 
 the micrometer." 
 
 "Mike who?" interrupted O'Rourke. 
 
 "Don't let that word bother you, as the instrument is not an 
 Irish invention, even if its. first name is Mike," rejoined 
 McAndrew. "It is more than likely it was invented by a 
 German; but at any rate it is a very useful measuring ma- 
 chine, by means of which, through the medium of an ac- 
 curately cut screw head and 'a graduated sleeve, thicknesses 
 of one-thousandth of an inch, and even of one ten-thousandth 
 inch can be readily measured. When you get to be engineers 
 you will find it very useful to save these leads, or spaghetti, 
 as O'Rourke calls them, for future reference. A convenient 
 way to do it is to get a large brown-paper book, a scrap- 
 book will do, and cut slits in the pages through which the 
 leads can be held in place. Mark under each set of three leads 
 the name of the bearing from which they were taken, the date, 
 and opposite several points in their length jot down the thick- 
 nesses in thousandths of an inch. 
 
CARE AND MANAGEMENT OF ENGINES 
 
 IQI 
 
 "Even if a crankpin has been adjusted to your satisfaction 
 by means of leads, it is always a wise precaution to put the 
 end of a pinch bar in between the end of the brass and the 
 crank-web, and if it does not move with a 'chug' after a quick 
 yank on the other end of the bar, the brasses are probably too 
 tight, and should be slacked up slightly until they can be 
 moved in that manner. 
 
 "When eccentric straps become noisy, they should be taken 
 apart and a small shim removed ; but they should never be 
 set up so tight that they cannot be moved all around by hand 
 after the bearing surfaces have been oiled. 
 
 "Journals connected with the valve gear do not need adjust- 
 ing very often, but when they do it is a comparatively simple 
 matter, especially if they are fitted with strap, gib and key 
 connections, as many of them are. When first constructed it 
 is usual to leave from 1/16 inch to H i ncn clearance between 
 the two brasses, so to adjust them afterwards it is only neces- 
 sary to drive the taper key in a little further, always beingi 
 sure to set up tightly on the set screw. 
 
 "Many small pin bearings where the wear is trifling are 
 fitted with solid bushings of brass. When they become badly 
 worn the bushings should be renewed. 
 
 "The making of new joints and packing small stuffing- 
 boxes should be attended to while the vessel is in port, as there 
 is nothing that annoys an engineer more while the vessel is 
 underway than to have one of these blow out. It is a strange 
 fatality, if I might call it that, that joints and stuffing-boxes 
 always give way at the most inopportune times. A joint will 
 run along perfectly tight while the ship is in a cold climate, 
 but just as soon as she gets down South, and on some par- 
 ticularly hot day, 'bang!' out blows the gasket, and fills an 
 already hot engine room full of steam and vapor. 
 
 "Then, too, it is generally the joint which is hardest, to get 
 at which lets go, while some joint that is easily remade will 
 
192 MC ANDREW'S FLOATING SCHOOL 
 
 run along as tight as a bottle for months at* a time. The 
 engineer who is onto his job will have all suspicions joints 
 remade while the vessel is tied up to the wharf and there is 
 time to do the job properly. 
 
 "The making of joints and packing of stuffing-boxes is 
 something you will have to learn from actual experience. 
 The various materials from which gaskets are made are as 
 numerous as the first man up San Juan Hill, and some of 
 them just about as reliable. As a rule, you should use only 
 rubber gaskets for joints in water pipes. For steam joints 
 various fibrous materials, asbestos woven with wire and 
 usudurian are the best and last longest. In making steam 
 joints you must be exceedingly careful to see that all the old 
 material is scraped from both flanges, and that the flanges 
 themselves are parallel. The holes in the gasket should be 
 cleanly cut, and before it is slipped in place the packing 
 should be smeared over on both sides with black lead and 
 tallow or cylinder oil. Set up on the bolts just as tightly as 
 possible, but not so hard as to twist some of them off, as is 
 done occasionally by muscular young men like O'Rourke." 
 
 "Honest Injun, chief, that wasn't me that twisted that stud 
 off the feed pump this morning. I won't say just who it was, 
 but I think he can speak German," protested O'Rourke. 
 
 "Oho ! so one of you is guilty of that very same thing only 
 this morning, eh? Well, whichever one of you highbrows it 
 was will have the pleasure of putting in a new stud while you 
 are resting yourselves off watch to-morrow. 
 
 "As I was saying," resumed McAndrew, "the bolts on a 
 new joint should be set up as tightly as possible, and then 
 after steam has been on the pipe for an hour or so, they 
 should be followed up, as the saying is, as the heating of 
 the gasket usually allows a little more tightening. 
 
 "In packing stuffing-boxes, the turns of packing should be 
 put in so that the joints do not come opposite one another, 
 
CARE AND MANAGEMENT OF ENGINES IQ3 
 
 and this packing should also be rubbed down with black lead 
 and tallow." 
 
 "Why do you do that, chief?" asked Nelson. 
 
 "It isn't that it does any particular good in keeping the 
 stuffing-box tight, but it makes it much easier to remove the 
 packing when it is worn out and again has to be repacked. 
 In marine engineering, no matter what you do in the way of 
 construction or repairs, you must provide for all manner of 
 things which may happen in the future. You don't want to be 
 caught like the man who built a boat having a 6-foot beam in 
 a cellar with only a 3-foot door to get it out of and didn't 
 notice the difference until the boat was finished. 
 
 "Certain parts of marine machinery need to be inspected to 
 see that everything is in good condition. I don't believe, as 
 some engineers apparently do, in taking an engine or an 
 auxiliary apart to see what makes it work so well, but at regu- 
 lar periods, say every three or four months, the cylinder 
 heads should be lifted to see that none of the follower bolts 
 is cracked or has become loose. Water ends of air pumps, 
 feed pumps and bilge pumps should be examined quite fre- 
 quently to see that the valves have not become too much worn 
 and the springs are not broken and are in their proper places. 
 This is particularly necessary if rubber valves are used. The 
 main condenser should be watched closely to see that no leaks 
 have developed in the tubes. This is generally indicated by 
 the water getting too high in the gage glasses on the boilers, 
 as salt water will leak through the tubes to the fresh water 
 side of the condenser and mix in with the feed water, causing 
 a surplus. If you have reason to suspect that any of the 
 tubes are leaking the condenser should be filled with water, 
 the water chest at each end removed, and the ends of all the 
 tubes examined carefully to see if any water is running out. 
 If it does, that indicates that the tube is leaking and it should 
 be removed at once. If there are spare tubes on hand fit one 
 
IQ4 M C ANDREW S FLOATING SCHOOL 
 
 of them in its place or else plug up the holes in the tube 
 sheets. 
 
 "After several months of use, condenser tubes become 
 covered with grease from the exhaust steam and fall off in 
 their efficiency of transmitting the heat from the exhaust 
 steam to the circulating water. This is generally indicated 
 by the vacuum falling below its usual height, and the con- 
 denser should be boiled out with a strong solution of soda and 
 water heated by means of a jet of steam. 
 
 "There are, of course, many other jobs to be attended to 
 while a vessel is in port; in fact, the duties of an engineer 
 while the vessel is tied up remind me of the tribulations of a 
 12-year-old playmate of mine when I was a youngster. He 
 would get home from school about 4 o'clock in the afternoon, 
 and upon reporting to his fond stepmother would every day 
 be saluted about as follows : 'Now, Lewis, you hurry up and 
 get ten or twelve baskets of chips from the shipyard ; run up 
 to the grocery store for me; hoe five rows of potatoes; chop 
 the kindling for the morning; get six pails of water and then 
 you can play the rest of the time before supper.' 
 
 "After performing all the numerous chores I have told you 
 about which have to be done in port the average engineer who 
 follows the sea can play the rest of the time; but I am afraid 
 that it is mostly after supper that he finds the opportunity." 
 
CHAPTER XX 
 
 Examination Questions and Answers 
 
 Since the last lecture to his class McAndrew had been so 
 busy with his regular duties that nearly a month had elapsed 
 before another opportunity offered to give the boys in the 
 Floating School further instruction. In the meantime the 
 four young men had continued their studies, using such text- 
 books as they had on hand for the purpose. It seems that 
 Pierce, who was somewhat more ambitious than his ship- 
 mates, had, at about the time that the Chief commenced their 
 instruction, enlisted as a student in one of the large cor- 
 respondence schools and taken up its course in marine engi- 
 neering. The text-books furnished with the course were very 
 comprehensive, and Pierce had kindly loaned them to his 
 fellow students, so that all had profited by studying them. 
 
 McAndrew commenced his remarks by saying, "We have 
 now covered, in a somewhat brief manner, to be sure, nearly 
 all the principal subjects necessary for an elementary under- 
 standing of marine engineering. It is now up to you to put 
 in practice some of the things I have told you. To get your 
 'tickets' as assistant engineers is, of course, your ambition. 
 The best way to prepare for your examination for a license 
 is to work out some of the questions which have been asked 
 by the steamboat inspectors. The existing laws in the United 
 States concerning licenses are somewhat vague in regard to 
 examinations, and I will quote you the following extracts 
 from the statutes, which will be of interest to you : 
 
196 MC ANDREW'S FLOATING SCHOOL 
 
 " 'No person shall receive an original license as engineer or 
 assistant engineer who has not served at least three years in 
 the engineer's department of a steam vessel. * * * 
 
 " 'Any person who has served three years as apprentice to 
 the machinist trade in a marine, stationary or locomotive 
 engine works, and any person who has served for a period of 
 not less than three years as a locomotive or stationary engi- 
 neer, or any person graduated as a mechanical engineer from 
 a duly recognized school of technology, may be licensed to 
 serve as an engineer of steam vessels after having had not 
 less than one year's experience in the engine department of 
 steam vessels, a portion of which experience must have been 
 obtained within the three years preceding his application, 
 which fact must be verified by the certificate in writing of the 
 licensed engineer or master under whom the applicant has 
 served, said certificate to be filed with the application of the 
 candidate; and no person shall receive license as above, ex- 
 cept for special license, who is not able to determine the 
 weight necessary to be placed on the lever of a safety valve 
 (the diameter of valve, length of lever, distance from center 
 of valve to fulcrum, weight of lever, and weight of valve and 
 stem being known) to withstand any given pressure of steam 
 in a boiler, or who is not able to figure and determine the 
 strain brought on the braces of a boiler with a given pressure 
 of steam, the position and distance apart of braces being 
 known, such knowledge to be determined by an examination 
 in writing, and the report of examination filed with the ap- 
 plication in the office of the local inspectors, and no engineer 
 or assistant engineer now holding a license shall have the 
 grade of the same raised without possessing the above quali- 
 fications. No original license shall be granted any engineer 
 or assistant engineer who cannot read and write and does not 
 understand the plain rules of arithmetic/ 
 
 "So far as the letter of the law is concerned it would seem 
 
EXAMINATION QUESTIONS AND ANSWERS 197 
 
 to be very easy for you to get a license, providing you can 
 solve the two problems called for in the above qualification. 
 But do not fool yourselves by thinking that you can get away 
 with a ticket so easily; while the law on the subject is very 
 old and not brought up to date, you will find that the ex- 
 aminers are very much alive to present conditions. While the 
 law requires satisfactory answers to only those two ques- 
 tions, it does not prohibit further questioning by the inspec- 
 tors, and if you ever pass your examinations you will find 
 that you must be pretty well posted in about every subject 
 connected with the business." 
 
 "Chief," inquired O'Rourke, "I see that you can get a 
 ticket inside of a year if you are a graduate how about 
 graduates from our school?" 
 
 "I am afraid," replied McAndrew, "that our .little school 
 here would not score very heavily as a 'fecognized school of 
 technology' ; but do not be alarmed about that. Where there 
 is one licensed marine engineer who is graduated from a 
 'recognized school of technology' there are at least forty-nine 
 who have graduated from the College of Practical Experience 
 and Self-Help. This little Floating School of ours is simply 
 a branch of that college. 
 
 "You will notice that the law requires that every candidate 
 must understand the plain rules of arithmetic. I know that 
 you all understand these rules, but I am not so sure that you 
 all understand the plain rules of mensuration, or the measure- 
 ments of area and volume. No one can pass the examination 
 who does not understand these rules, so I will devote a few 
 moments to explaining them to you. 
 
 MEASUREMENT OF AREAS AND VOLUMES 
 
 "To find the area of any plain rectangular figure, that is, 
 one having four square corners, you multiply the length by 
 
IQo MC ANDREW S FLOATING SCHOOL 
 
 the breadth. Thus the side of a rectangular tank 8 feet long 
 and 4 feet wide will contain 8 X 4 = 32 square feet. 
 
 "To find the volume of a rectangular tank we must multiply 
 the length, breadth and depth together. Thus if the above 
 tank is 4 feet in depth it will contain 8 X 4 X 4 128 cubic 
 feet. 
 
 "A circle is defined as a figure every point of whose cir- 
 cumference or boundary is equally distant from a point within 
 called the center. You are familiar with how it is drawn with 
 a pair of compasses. The diameter of a circle is the length of 
 a line drawn across it and through its center. To find the 
 length of the circumference, or distance around the circle, we 
 multiply the diameter by the figures 3.1416. Thus if the 
 diameter of a barrel is 2 feet, the circumference will be 2 X 
 3.1416, or 6.2832 feet. 
 
 "You will very often be required to find the area of a 
 circle ; the way to do it is to square the diameter ; that is, 
 multiply it by itself, and then multiply the quotient by the 
 figures .7854. If you are told that a high-pressure cylinder is 
 30 inches in diameter, to find its area you first multiply 30 X 
 30, and get 900. Then 900 X -7854 = 706.86 square inches, 
 the area. 
 
 "You must always remember those two 'constants/ as they 
 are termed, 3.1416 for the circumference and .7854 for the 
 area of a circle, as you will often have use for them when 
 you do not have time to hunt them up in the text-books." 
 
 "I can remember them," said O'Rourke. "It's just as easy 
 as remembering 4-11-44." 
 
 "Yes, and much more useful," said the instructor. 
 
 "It is also quite important for you to know how to find 
 the volume and area of a cylinder. For example, if you are 
 going to cover a tank with asbestos, you would want to know 
 how to find the total area. A cylinder, you know, is a figure 
 which if cut across perpendicular to its axis at any point 
 
EXAMINATION QUESTIONS AND ANSWERS 199 
 
 beteween the top and bottom will be circular in section. 
 Hence if we have a cylindrical tank 5 feet in diameter and 
 10 feet high, and wanted to know how much material was 
 needed to cover it all over, we would first find the circum- 
 ference of a circle 5 feet in diameter, which is 5 X 3.1416 = 
 15.708 feet. Multiply this by the height, 10 feet, and we have 
 10 X 15708 = 157.08 square feet to cover all around the 
 sides. 
 
 "How would you find the amount of covering for the ends, 
 O'Rourke?" 
 
 "Multiply her by .7854," replied the young man. 
 
 "Multiply what?" 
 
 "Why, the 5 feet diameter, of course," confidently said 
 O'Rourke. 
 
 "There's where you're wrong, as usual. I told you that in 
 order to find the area of a circle you must square the diam- 
 eter. So we have 5 X 5 = 25 and 25 X -7^54 = 19.635 square 
 feet as the area of one end. But there are two ends, so we 
 must allow for twice that, or 39.27 square feet. This added 
 to 157.08 gives us 196.35 square feet as the total surface of 
 the tank. 
 
 "It is of equal importance for you to be able to find the 
 volume of a cylinder, or how much it will hold if it is 
 hollow, or how large it is if solid. For example, we want to 
 know how many gallons of oil or water a tank like the above 
 will hold. To do this we must first find the area of the 
 circle, which from the above we know to be 19.635 square 
 feet, and as it is simpler to calculate it in inches we multiply 
 this number by 144, or 19.635 X 144 2827.4 square inches. 
 Right here I want to warn you against a mistake that so 
 many beginners fall into; that is, of multiplying feet by 
 inches. Remember, feet must always be multiplied by feet 
 and inches by inches, or your answer will be wrong. Hence 
 the height or depth of this tank being 10 feet, we must use 
 
2OO MC ANDREWS FLOATING SCHOOL 
 
 10 X 12, or 120 inches, as the multiplier. Then we have 
 28274 X I2 o = 339,288 cubic inches as the volume of the 
 tank. There are 231 cubic inches in a gallon, so we divide the 
 total number of cubic inches in the tank, 339,288 by 231, and 
 we find in even numbers that the tank will contain 1,469 
 gallons. 
 
 "There are not many spherical surfaces around marine 
 machinery, but it might be useful at some time for you to 
 know how to find the volume and surface of a sphere or ball. 
 This is defined as a solid bounded by a curved surface, every 
 point of which is equally distant from a point within known 
 as the center. Any line through the center and cutting the 
 surface is the diameter. We will suppose that we have a ball 
 float in the feed tank 12 inches in diameter, and want to know 
 how much sheet copper it will take to make such a float. The 
 rule is to square the diameter and multiply by our old friend 
 3.1416. Thus 12 X 12 = 144 and 144 X 3-14*6 = 452.39 
 square inches as the surface of the ball. Now if we had a 
 cast iron ball 6 inches in diameter hanging on a safety valve 
 lever, and wanted to know its weight, we would first find its 
 volume in cubic inches. To do this the rule is to cube the 
 diameter; that is, multiply it by itself twice, and multiply 
 that product by .5236. Thus in this case it would be 
 6X6X6 = 216, and 216 X -5236 = 113.1 cubic inches in 
 the ball. Knowing that cast iron weighs .26 pound to the 
 cubic inch we multiply 113.1 by .26, and find that the ball 
 weighs 29.41 pounds." 
 
 "Chief, could you use that rule to find the weight of a 
 highball ?" inquired O'Rourke. 
 
 "From all I can hear of the subject highballs haven't much 
 weight, as their general tendency is to make you light-headed," 
 suggested McAndrew. 
 
EXAMINATION QUESTIONS AND ANSWERS 201 
 
 SAFETY VALVE PROBLEMS 
 
 "Now we are ready for the all-important safety valve 
 problem, and I am particularly anxious to have you under- 
 stand the principle upon which it is worked, rather than to 
 learn some particular example, as is too often the case with 
 beginners. When you come up for examination you will find 
 that the conditions given you will be entirely different from 
 any problem you may have worked out. The following is an 
 outline sketch, which will enable you to follow out the 
 principle involved. 
 
 "In Fig. 37, O represents the fulcrum, or point where the 
 lever is hinged; V represents the valve; N the center of 
 
 1 
 
 ftr 
 
 FIG. 37. SAFTETY VALVE PROBLEM 
 
 gravity of the lever ; that is the point where, if the lever 
 should be picked up in your hand, it would exactly balance 
 and remain in a horizontal position. M represents the point 
 where the weight W is located on the lever. The forces act- 
 ing on the lever at M and N have a tendency to make it fall 
 or rotate in a direction opposite to the hands of a watch. 
 The weight of the valve and stem at S also has that ten- 
 dency. The only upward force, or the only force tending 
 to make the lever turn in the same direction as the hands of 
 a watch, is the pressure of the steam on the valve V , operating 
 on the lever at the point S. Now, safety valve levers are not 
 supposed to be rotating in either direction, but to remain in 
 equilibrium, hence the downward forces must be such as to 
 balance the upward force, and the only force that can be 
 
2O2 MCA^REW'S FLOATING SCHOOL 
 
 adjusted to bring them all in equilibrium is that of the weight 
 W. This can be done either by varying the weight itself or 
 by moving it out or in from the fulcrum O. 
 
 "The tendency to cause the lever to rotate about the ful- 
 crum, with a ball of a given weight, varies with the distance 
 the ball is from the fulcrum exactly as the principle of the 
 levers, which I have explained to you before. To measure 
 this tendency you multiply the weight by the distance from 
 the fulcrum, and the product is known as the moment. Thus 
 a weight of i pound, placed 4 feet from the fulcrum, would 
 have a moment of 4 foot-pounds to cause rotation. Similarly, 
 a weight of 4 pounds placed only i foot from the fulcrum 
 would have the same moment of 4 foot-pounds. If the dis- 
 tances were given in inches we would speak of the moments 
 in so many inch-pounds. 
 
 "To illustrate these principles, suppose in Fig. 37 we were 
 given the following quantities : 
 
 Distance OS from fulcrum to center of valve 6 inches. 
 
 Weight of valve and stem 8 pounds. 
 
 Diameter of the safety valve 3 inches. 
 
 Steam pressure 50 pounds. 
 
 Weight of lever 10 pounds. 
 
 Center of gravity of lever 20 inches from fulcrum. 
 
 Distance of weight (OM) from fulcrum 30 inches. 
 
 Required, the size of the weight necessary to keep the 
 valve in equilibrium when steam is at 50 pounds 
 pressure. 
 
 "The upward tendency is represented by the pressure of 
 the steam at S. A valve 3 inches in diameter has an area of 
 7.07 square inches ; this, multiplied by 50, the pressure per 
 square inch, gives us a total upward pressure of 353.5 pounds. 
 But this is 6 inches from the fulcrum, so the moment will be 
 353-5 X 6 = 2,121.0 inch-pounds. 
 
 "All the other weights exert downward forces and tend to 
 
EXAMINATION QUESTIONS AND ANSWERS 2O3 
 
 affect this upward pressure, so we will have the following to 
 work against the 2,121 inch-pounds moment of the valve. 
 
 "Weight of valve and stem (8 pounds) multiplied by lever 
 arms (6 inches) equals 48 inch-pounds. 
 
 "Weight of lever (10 pounds) multiplied by distance OA r 
 (20 inches) equals 200 inch-pounds. 
 
 "We do not yet know the size of the weight W , but we 
 do know its distance from the fulcrum (30 inches), hence we 
 add 48 and 200, and find the sum to be 248, and subtract it 
 from 2,121 and find we have 1,873 inch-pounds to make the 
 downward moments equal to the upward moments. This 
 1,873 is in inch-pounds, hence dividing it by 30 inches will give 
 us 62.4 pounds as the size of the weight to maintain the 
 balance. 
 
 "We will suppose that the weight (62.4) had been given us, 
 and we were asked to ascertain what distance it should be 
 located from the fulcrum in order to balance 50 pounds pres- 
 sure on the valve. In this case we would have the same 
 upward pressure from the valve, or 353.5 pounds, and the 
 moment of 2,121.0 inch-pounds. The downward forces for the 
 weights of the valve and stem and the lever will be repre- 
 sented by a total of 248 inch-pounds. As before, subtract 
 this from 2,121 and we have 1,873 inch-pounds. Knowing the 
 size of the weight in pounds (62.4) we divide it into 1,873, 
 and find that the weight should be located 30 inches from the 
 fulcrum in order to be in balance. 
 
 "Another way the problem might be given you is to find 
 out what the steam pressure would be with all the conditions 
 given as above. The downward pressures would be as before : 
 
 Inch-Pounds 
 
 Valve and stem, 8 pounds X 6 inches = 48 
 Lever, 10 pounds X 20 inches = 200 
 
 Weight, 62.4 pounds X 30 inches = 1,873 
 
 Total. 2,121 
 
2O4 MC ANDREW'S FLOATING SCHOOL 
 
 "We know that the area of the valve is 7.07 square inches, 
 and its lever arm, or distance from the fulcrum, is 6 inches, 
 so we have 7.07 X 6 42.42. As there is only the one force 
 acting upward we divide 2,121 by 42.42, and find that a pres- 
 sure of 50 pounds can be carried with the weight set in the 
 position given. 
 
 How TO FIGURE THE STRESSES ON BOILER BRACES 
 "The next problem we will take up is the one required by 
 law: 'to figure and determine the stresses brought on the 
 braces of a boiler with a given pressure of steam, the position 
 and distance apart of braces being known.' 
 
 "This is very simple, as it only involves multiplication. 
 Thus if the braces are spaced 12 inches apart each way, and 
 the steam pressure is 160 pounds per square inch, we multiply 
 12 by 12, and find that there are 144 square inches to be sup- 
 ported, and 144 X ico = 23,040 pounds stress which is brought 
 on one brace. Similarly, if the braces are spaced 14 inches 
 apart horizontally and 10 inches vertically, and the steam 
 pressure is 160 pounds per square inch, we would multiply 
 14 by 10, and find that there is an area of 140 square inches 
 to be supported by one brace, and 140 X 160 would give us 
 22,400 pounds, or an even 10 tons, as the total stress on one 
 brace. 
 
 "The inspectors, however, do not confine themselves to this 
 simple form of the problem, and you are liable to get one 
 like the above, with the addition that they would ask you the 
 safe diameter of the brace. To perform this we must know 
 the United States rules as to the safe working load per 
 square inch of section. These rules give allowances of 6,000 
 pounds per square inch of section for iron ; above 5 square 
 inches sectional area if steel is used and regularly inspected 
 an allowance of 8,000 pounds per square inch is made; braces 
 above i l /4 inches diameter are not allowed to exceed 9,000 
 
EXAMINATION QUESTIONS AND ANSWERS 20$ 
 
 pounds per square inch of section if such stays are not 
 forged or welded. 
 
 "You might get a question similar to the following: What 
 diameter of bracing should be used to support a flat surface 
 12 inches by 12 inches, using steam at 200 pounds pressure? 
 The solution would be 12 X 12 = 144, and 144 X 200 = 
 28,800 pounds to be supported; 28,800 -4- 9,000 = 3.2 square 
 inches. Looking at a table of areas we would find that a stay 
 having a diameter of 2 1/16 inches has an area of 3.341 square 
 inches, which is the nearest area to the one we know to be 
 necessary. Very likely these braces would be made 2 l /% 
 inches in diameter, as that would be the nearest commercial 
 size obtainable. 
 
 ALLOWABLE WORKING PRESSURE ON A BOILER 
 "Possibly you will be asked how to find what pressure will 
 be allowable on a Scotch boiler, knowing the thickness of 
 shell, the diameter of the boiler, tensile strength of plate, etc. 
 "The United States Government rule is to multiply one- 
 sixth of the lowest tensile strength in pounds by the thick- 
 ness in inches, and divide by one-half the diameter, also in 
 inches ; 20 percentum is to be added if double riveting is used 
 for the horizontal seams, which, of course, would be used 
 these days ; in fact, the seams would probably be triple- 
 riveted, but the rule makes no allowance for that. 
 
 "For example, if we had a boiler 15 feet in diameter, made 
 of steel plates, the lowest tensile strength of which was 
 Co,ooo pounds per square inch, and the shell was i l / 2 inches 
 In thickness, and we wanted to find what presure would be 
 allowed by the inspectors, we would proceed as follows : 
 15 feet X 12 = 180 inches diameter. 
 One-half of 180 = 90 inches. 
 
 One-sixth of the lowest tensile strength (60,000 pounds) 
 = io,oco pounds. 
 
2o6 MC ANDREW'S FLOATING SCHOOL 
 
 i}/2 inches =1.5 inches. 
 10,000 X 1.5 = 15,000. 
 15,000 -=- 90 = 166.6 pounds. 
 
 "As double riveting allowances must be made, we add 20 
 percent of this and have 166.6 -f- 33.4 = 200 pounds pressure 
 allowable on the boiler." 
 
 "Chief," said Pierce, "suppose we wanted to find out what 
 thickness to make this boiler shell, and we knew the size and 
 pressure we wanted to carry?" 
 
 "We would simply reverse the operation," replied 
 McAndrew. "In other words, multiply the radius in inches 
 by the pressure in pounds and divide by one-sixth the tensile 
 strength. Thus 90 X 200 = 18,000; 18,000 -f- 15,000 = 1.2 
 inches thick. But for double riveting an allowance of 20 
 percent additional is made, and 1.2 is only 80 percent 
 (100 20) of the thickness allowance. As 80 percent is 1.2, 
 100 percent will be 1.5 inches, the thickness which we will 
 have to make the boiler shell in order to withstand the. pres- 
 sure required and conform to the rules. 
 
 "Strange to say, all the problems required by law to be 
 given candidates for engineers' licenses in this country relate 
 to boilers. These laws were passed in the early days of steam 
 navigation, and I presume that the legislators in those days 
 thought that if a man understood boilers thoroughly he could 
 manage somehow to run the engines. Fortunately for the 
 good of the service the inspectors ask questions concerning 
 nearly all parts of the steam machinery, so it is well to be 
 prepared in a general way." 
 
 "Why can't we get some of the old examination papers?" 
 observed Nelson. 
 
 "Just try it for yourself and see," said McAndrew. "In 
 the first place they are not published, so it is not necessary 
 to give any other reasons. 
 
 "I have, however, put down in my notebook a number of 
 
EXAMINATION QUESTIONS AND ANSWERS 2O7 
 
 the questions that were asked me on my different examina- 
 tions, and I will give you the benefit of some of those I have 
 had, and also of some of those I have obtained from other 
 engineers. They are as follows: 
 
 QUESTIONS AND ANSWERS FROM MARINE ENGINEERS' 
 EXAMINATION PAPERS 
 
 Q. What is the advantage of a triple-expansion engine over 
 a compound ; how is the power divided ; how can you tell 
 when the power is equally divided? 
 
 A. Greater economy, due to a greater degree of expansion 
 of the steam ; the power should be divided as nearly equally 
 as possible between the three cylinders ; the only way to ascer- 
 tain whether the division is equal or not is to take a set of 
 cards from each cylinder and calculate the horsepower which 
 each develops. 
 
 Q. What are the principal types of condensers? 
 
 A. Jet and surface. 
 
 Q. What are the necessary appliances for operating a sur- 
 face condenser? 
 
 A. The circulating pumps for forcing the cooling water 
 through the tubes, and the air pump for pumping out the 
 condensed water and the vapor from the interior of the 
 condenser. 
 
 Q. How would you ascertain if a condenser was leaking 
 salt water? 
 
 A. By taking off the water chest at each end and filling 
 the condenser with fresh water. If any water runs out 
 through the ends of the tubes there are leaks in the tubes, 
 which, when the condenser is in operation, would admit salt 
 water to the condenser. 
 
 Q. How many sets of valves are there in an air pump; 
 which set could be dispensed with and the pump continue to 
 work? 
 
2o8 MC ANDREW'S FLOATING SCHOOL 
 
 A. The valves are known as foot valves, bucket valves and 
 discharge valves. The pump could run without foot valves, 
 but it works better with them. 
 
 Q. What is a vacuum ? 
 
 A. A vacuum means absence of air. 
 
 Q. What is steam? 
 
 A. Steam is a thin, invisible, elastic vapor formed by the 
 application of heat to water. 
 
 Q. Is it possible to get a perfect vacuum? 
 
 A. It is not. 
 
 Q. If a vacuum gage shows 24 inches, how many pounds 
 pressure does that indicate? 
 
 A. About 12 pounds. 
 
 Q. Suppose the steam gage shows 60 pounds and the 
 vacuum gage 24 inches, what would be the pressure in pounds 
 per square inch on the piston? 
 
 A. One-half of 24 inches means a pressure of 12 pounds, 
 so the pressure per square inch on the piston would be 60 + 
 12 = 72 pounds. 
 
 Q. What is the duty of a condenser? 
 
 A. A condenser serves the purpose of condensing or turn- 
 ing the exhaust steam back into its original state as water; in 
 this operation a vacuum is formed which increases the power 
 of the engine by carrying out the expansion of the steam to 
 nearly its limit. 
 
 Q. How does a leaky condenser affect a boiler? 
 
 A. It allows salt water to be fed to the boiler, and if the 
 leak is extensive it will cause too great a quantity of water 
 to accumulate in the boiler, so that the boiler will have to be 
 blown down at intervals. 
 
 Q. Describe the course of steam from the boiler to a triple- 
 expansion engine, naming the valves and pipes, etc., it passes 
 through until in the form of water it reaches the feed tank? 
 
 A. The steam after being formed in the boiler first passes 
 
EXAMINATION QUESTIONS AND ANSWERS 2OO, 
 
 through the dry-pipe, the object of which is to keep the water 
 out of the steam. It then passes through the main stop valve 
 on the boiler into the main steam pipe. In the main steam 
 pipe is sometimes fitted a separator which removes the water 
 from the steam. Passing through the throttle valve it enters 
 the high-pressure steam chest, thence through the high- 
 pressure valve into the high-pressure cylinder ; after a certain 
 degree of expansion in that cylinder it is exhausted into the 
 first receiver, and passing through the intermediate valve it 
 enters the intermediate cylinder, where another degree of 
 expansion ensues. It is exhausted from the intermediate 
 cylinder into the second receiver, and thence through the low- 
 pressure valve into the low-pressure cylinder, where it is 
 expanded to its final stage and then is exhausted into the 
 condenser. There it is transformed into water by coming in 
 contact with the surface of the cold tubes. This water is 
 pumped out of the bottom of the condenser by means of the 
 air pump, and is discharged into the feed tank, whence 
 it is again pumped into the boilers by means of the feed 
 pump. 
 
 Q. Where should the throw of the eccentric be placed in 
 relation to the crank of a slide valve engine? 
 
 A. It should be set ahead of the crank where the steam is 
 taken on the outside of the valve. 
 
 Q. How would you set an eccentric on a new shaft to have 
 the valve properly set? 
 
 A. Ninety degrees ahead of the crank, plus the amount of 
 the lap, plus the amount of the lead. Before setting the 
 eccentric you should lock it with a set screw, and then by 
 turning the engine around one revolution see that the lead is 
 correct for both ends. After it is found to be in the correct 
 position then mark and cut the keyway in the shaft. 
 
 Q. What is meant by lap? 
 
 A. The amount a slide valve overlaps the steam port, when 
 
210 MC ANDREW'S FLOATING SCHOOL 
 
 it is in mid-position, if it is on the steam side. On the exhaust 
 side it is the amount it overlaps the exhaust side. The former 
 is used for regulating the cut-off and the latter to provide 
 compression at each end of the stroke. 
 
 Q. What is meant by lead ? 
 
 A. By lead is meant the amount the valve is open when the 
 piston is at the end of its stroke. Lead is given to admit 
 steam before the piston reaches the end of the stroke, and to 
 start it off promptly on the new stroke. 
 
 Q. Can steam be cut off equally in the two ends of a cylin- 
 der when using a lap valve? 
 
 A. No, it cannot, for the reason that the crank is not hori- 
 zontal when the piston is at half stroke, but a little above the 
 center, due to the angularity of the connecting rod. When 
 the crank is horizontal the piston is a little below the center 
 of its stroke, therefore the steam follows further on the top. 
 
 Q. Is the lead increased or decreased by shifting the link 
 to mid-position? 
 
 A. If you have "open" rods the lead will increase as we 
 run in the links, and we shorten the point of cut-off. If the 
 rods are crossed the opposite is the case. 
 
 Q. What are the practical limits of cutting off with a slide 
 valve ? 
 
 A. It is not practicable to cut off very short with a lap 
 valve, on account of the excessive lap necessary and the in- 
 creased travel of the valve. Generally speaking, it is inad- 
 visable to cut off at less than ^ the stroke, nor more than %. 
 
 Q. What is the difference in the throw of an eccentric of a 
 double-ported valve from that necessary for a single-ported 
 valve ? 
 
 A. Double-ported valves are used to reduce the travel of a 
 valve by giving a double admission at each end, hence the 
 travel is only one-half that of a single-ported valve. 
 
EXAMINATION QUESTIONS AND ANSWERS 211 
 
 Q. Find the area of opening in a boiler shell for a duplex 
 safety valve, each valve being 3^ inches diameter. 
 
 A. 3-5 X 3-5 = 12.25, this multiplied by .7854 = 9.62 as the 
 area of one valve ; 9.62 X 2 = 19.24 as the area of the hole 
 in the boiler. The diameter corresponding to that area is 
 practically 5 inches. 
 
 Q. What is meant by foaming or priming? How do you 
 explain the cause? 
 
 A. "Foaming" is the violent boiling or ebullition of the 
 water in the boiler, the water level rises and falls rapidly, and 
 water gets mixed with the steam and is carried to the engine; 
 this latter action is known as "priming." Foaming is liable to 
 occur when the boiler is dirty; when the boiler is forced to a 
 great extent; when changing from salt to fresh feed; when 
 too much soda is used in the boiler, or if the boiler does not 
 have sufficient steam space. 
 
 Q. How would you check "foaming"? 
 
 A. Slow down the engine ; put on a strong feed ; pump and 
 blow if necessary. 
 
 Q. What precautions are necessary when the boiler is 
 priming? 
 
 A. Open all cylinder and valve chest drains, and if neces- 
 sary slow down the engine. 
 
 Q. What are the bad effects of oil or grease getting into the 
 boilers? 
 
 A. The oil forms a scum on the surface of the water in the 
 boiler, and gradually collects together with particles of salt 
 scales, sulphate of lime, etc., and will finally settle on the 
 tubes or on the furnace crowns. Being a very poor conductor 
 of heat it is liable to cause the metal to become overheated, 
 with consequent collapse or bulging of the furnaces. The oil 
 will also become decomposed, form acids and expedite elec- 
 trolytic action, with its consequent pitting of the steel plates 
 and tubes. 
 
212 MC ANDREWS FLOATING SCHOOL 
 
 Q. What density would you carry the water in the boiler, 
 using a high-pressure of steam, such as 180 pounds? 
 
 A. With steam at that pressure allow the density to rbe as 
 high as 4 or 4^2 thirty-seconds before blowing, as with high 
 temperature if we keep blowing to hold the density low, we 
 increase the scale as the calcium sulphate in the sea water 
 deposits at the comparatively low temperature of 290 de- 
 grees F. 
 
 Q. How would you determine the density of boiler water 
 if the salinometer was out of order? 
 
 A. By means of noting the boiling point. Fresh water boils 
 at 212 degrees F. under atmospheric pressure only. Ordinary 
 sea water boils at 213.2 degrees F. At a density of 2 thirty- 
 seconds it boils at 214.2 degrees F., and so on. 
 
 Q. How high should the water be carried over the tops of 
 combustion chambers? 
 
 A. Not less than 6 inches. 
 
 Q. Describe a fusible plug. Where are they placed in a 
 boiler? and for what purpose? What materials are used in 
 their construction? 
 
 A. A fusible plug is usually made of brass, filled with Banca 
 tin. They are to relieve the pressure in case of low water 
 in the boiler, the theory being that the tin will melt out when 
 there is no water over it, and allow the steam to blow through 
 the hole thus formed. In boilers having combustion chambers 
 they must be placed in the top, or the highest heating surface. 
 In flue boilers one must be placed in each flue and one in the 
 shell of the boiler from the inside just below the fire line, and 
 not less than 4 feet from the forward end of the boiler. 
 
 Q. Where would you use a soft patch on a boiler, and how 
 should it be applied? 
 
 A. A soft patch should be used over a weak spot on the 
 boiler, or over a part of a joint where the rivets are cor- 
 roded away and leaking. It should never be used where it 
 
EXAMINATION QUESTIONS AND ANSWERS 213 
 
 will come in contact with the fire or flames. It is usual to 
 make them of 3/i6-inch or ^-inch plate, and of a size suf- 
 ficient to overlap all portions of the weak spot to be patched. 
 A templet of lead should be made for the patch. The patch 
 itself should be made to correspond to the templet; it should 
 be lipped around its edges, so as to hold the putty of red lead 
 and iron filings. Each bolt should be fitted with washers and 
 grommets of asbestos thread rubbed down with white lead. 
 Bake the patch with heated irons and set up as tightly on the 
 bolts as possible. 
 
 Q. Where on a boiler would you use a hard patch, and how 
 should it be applied ? 
 
 A. A hard patch is used for a permanent job, and can be 
 fitted over a hole or defective part of the boiler, even if it 
 does come in contact with the fire. The defective part should 
 be cut out, a templet made large enough to allow for a riveted 
 joint all around the hole. The holes should be drilled from 
 the templet, and when all is ready drive the rivets and calk 
 the edges all around the same as in regular boiler con- 
 struction. 
 
 Q. Upon what does the strength of a cylindrical boiler 
 depend ? 
 
 A. Upon the thicknes of the shell. 
 
 Q. Why are two safety valves used instead of one? 
 
 A. The combined area of the two valves must be equal to 
 the area of one valve, as required by the rules of the Steam- 
 boat Inspection Service. When two valves are used there is 
 less likelihood of both getting out of order than would be the 
 case if only one is used. 
 
 Q. What should be the angle of the seat of safety valves? 
 
 A. The seats should have an angle of inclination of 45 
 degrees to the center line of their axes. 
 
 Q. What determines the size of safety valves of different 
 kinds? 
 
214 MC ANDREW'S FLOATING SCHOOL 
 
 A. Lever safety valves must have an area of not less than 
 I square inch to 2 square feet of the grate surface. Spring 
 loaded safety valves must have an area of not less than i 
 square inch for each 3 square feet of grate surface, except for 
 watertube boilers carrying a steam pressure exceeding 175^ 
 pounds per square inch, when they are required to have an 
 area of not less than I square inch for each 6 square feet of 
 grate surface. 
 
 Q. Name all the valves on a boiler, stating the most im- 
 portant one and where it is placed. 
 
 A. The valves on a marine boiler are the safety valve, 
 main stop valve, auxiliary stop valve, main feed check valve, 
 auxiliary feed check valve, surface blow valve, bottom blow 
 valve, drain valve and sometimes a sentinel valve. 
 
 The most important one is the safety valve, which is placed 
 on the shell at the highest part of the boiler. 
 
 Q. What would be the result if both feed valves were shut 
 on a boiler and the engine was in motion at full speed? 
 
 A. The water in the boiler would be gradually used up, and 
 if not replenished the boiler would explode. 
 
 Q. Does the water in the glass always show the true level 
 in the boiler? 
 
 A. No, it does not. Occasionally the pipes leading to the 
 gage glass may become choked up with hardened oil, or the 
 valves may not be opened. These should be frequently tried 
 to see that they are kept open. 
 
 Q. A ship has six double-ended boilers with six furnaces, 
 each of which is 6 feet 6 inches long by 3 feet 3 inches in 
 diameter, and when the ship is making 15 knots there is 
 15 pounds of coal burned per square foot of grate area per 
 hour. How many tons of coal would be required for a voyage 
 of 3,000 miles, and how many tons would be burned each day ? 
 
 A. As each furnace is 6^2 feet long and 3*4 feet in diam- 
 eter, there would be &/ 2 X 3/4 = 21$^ square feet in each 
 
EXAMINATION QUESTIONS AND ANSWERS 215 
 
 furnace; 21 1 /& X 6 = 126^4 square feet of grate surface in 
 each boiler ; 12624 X 6 760^ square feet of grate surface 
 in all the boilers; 760^ X 15 = HA^7 l /2 pounds, or 5.09 tons 
 of coal burned per hour; 3,000 -=- 15 = 200 hours' time to 
 make the voyage of 3,006 miles ; 5.09 X 200 = 1,018 tons to 
 make the voyage of 3,000 miles; 5.09 X 24 = 122.16 tons 
 burned each day. 
 
 Q. If you were in charge of a modern triple-expansion 
 engine, and the intermediate connecting rod broke beyond 
 repair, what would you do? 
 
 A. Disconnect the rod at both ends; take out the inter- 
 mediate valve, so as to allow the steam to pass from the 
 high-pressure exhaust direct to the low-pressure valve chest 
 and proceed on the voyage, using only the high and low- 
 pressure cylinders. 
 
 Q. How long would you run a boiler if you had used only 
 fresh water as feed before cleaning it? 
 
 A. About 700 steaming hours with the main engine in use 
 would be about the safe limit before opening the boiler to 
 clean it, as it will be found at the end of that time that the 
 zincs will need renewing. 
 
 Q. If the high-pressure valve stem broke beyond repair 
 what would you do? 
 
 A. Take out the high-pressure valve and let the live steam 
 from the boilers blow directly through to the intermediate 
 valve chest, and run the engine compound with the inter- 
 mediate and low-pressure cylinders. 
 
 Q. How many gallons of water is pumped per hour by a 
 single-acting plunger pump, whose diameter is 6 inches, stroke 
 IO inches, and making 60 strokes per minute? 
 
 A. The area corresponding to a diameter of 6 inches is 
 28.27 square inches. This is found by multiplying 6x6 = 
 36 X 7854 = 28.27 square inches. Now 28.27 X 10 inches = 
 282.7 cubic inches per stroke; 282.7 X 60 = 16,962 cubic 
 
216 MC ANDREW'S FLOATING SCHOOL 
 
 inches per hour; 16,962 ~ 231 (number of cubic inches per 
 gallon) = 73.4 gallons per minute ; 734 X 60 4404 gallons 
 per hour. 
 
 Q. What are the principal things to look after upon taking 
 charge of a watch? 
 
 A. See first if there is a half a glass of water in each boiler, 
 that the fires are clean, that the ashes have been blown out, 
 that some coal is out on the plates, that no bearings are run- 
 ning warm, that the feed pump is working well, and that a 
 good vacuum is being carried. 
 
 Q. What height must a safety valve be raised or lifted to 
 allow a free escape of steam equal to the area of the valve? 
 
 A. One-fourth the diameter; thus with a 4-inch safety 
 valve it should be lifted i inch. 
 
 Q. Why are counterbores put into each end of a cylinder? 
 
 A. To allow the piston to run over the edge at each end of 
 the stroke, so that it will not wear shoulders in the bore of 
 the cylinder. 
 
 Q. A cylinder is 30 inches diameter, the steam pressure is 
 125 pounds, and 30 bolts hold the cylinder cover in place. 
 What is the stress on each bolt? 
 
 A. The area corresponding to 30 inches diameter is 30 X 
 30 X .7854 = 706.86 square inches, 706.86 X 125 = 88,357.5 
 pounds total stress on the cylinder cover; 88,357.5 -i- 30 = 
 2,945.25 pounds stress on each bolt. 
 
 Q. How should the valves be connected to a boiler? 
 
 A. They should always be bolted to the shell, never riveted 
 or screwed. 
 
 Q. How would you find out the distance the piston and 
 shaft had worked down? 
 
 A. It is customary to mark on the cross-head slipper and 
 cross-head guides the position of the piston at the top of the 
 stroke. If it has worked down from the original position the 
 amount will be the difference between the marks on the guide 
 
EXAMINATION QUESTIONS AND ANSWERS 217 
 
 and the slipper. A tram is usually furnished with every 
 engine showing the position of the top of the crankshaft, 
 relative to the facing on the top of the bed-plate under the 
 bearing caps. If the shaft is worn down, the distance can be 
 ascertained by fitting the tram in place on the bed-plate facing 
 and measuring the space between the tram and the top of the 
 crankshaft. 
 
 Q. What are the principal things to look after before start- 
 ing fires? 
 
 A. See that there is sufficient water in the boiler, that all 
 valves work freely, particularly the feed check valves ; that 
 the air cock or the top gage cock is left open, to allow the 
 air to escape, and that all man and hand-holes are set up 
 tightly. 
 
 Q. Before turning the engine over what precautions are 
 necessary for the engine and vessel? 
 
 A. Inform the deck officers so that they can see that suf- 
 ficient lines are out to hold the vessel to the wharf, and that 
 everything is clear around the propellers. In the engine-room 
 see that the turning gear is disconnected ; that the water ser- 
 vice is turned on ; that all bearings have been oiled ; that there 
 is nothing in the crank-pits, and that all hands are clear of the 
 engine. 
 
 Q. When the pumps are connected to the engine what 
 would you look after before starting? 
 
 A. See that the air pump is not filled with water, and that 
 all valves on the discharge side of the feed pumps or bilge 
 pumps are open. 
 
 Q. What are the causes of feed pumps working poorly? 
 
 A. Generally, bad management. Either the pumps are not 
 getting the water from the hot well regularly or the check 
 valves on the boilers may be closed. Possibly the valves in 
 the water end of the pump are out of order. 
 
 'The foregoing questions which I have quoted cover about 
 
2i8 MC ANDREW'S FLOATING SCHOOL 
 
 the usual ground that is embodied in the examination given 
 by the inspectors for your first papers. I do not mean to 
 imply that you will get any of these particular questions when 
 you go up for your tickets, but if you understand the princi- 
 ples upon which each of them is worked you ought to be 
 able to pass any examination which they give you. 
 
 "This will conclude my course of lectures to you. I know 
 I have not covered every subject in marine engineering, as 
 many volumes have been written on the subject. I have en- 
 deavored to give you a good general idea of what you will 
 have to know to be successful. You must not let up in your 
 studies, as no man can keep up to date unless he is constantly 
 studying. By that I do not mean that you should devote all 
 your spare time to books, but at your ages you should give 
 at least one hour a day of your time off watch to studying 
 some of the many subjects connected with your business." 
 
 "Chief, can you recommend us some good books to get?" 
 queried Pierce. 
 
 "Oh ! yes, indeed I can ; there are lots of good books which 
 you can buy which will be very helpful to you. For example, 
 there are several correspondence schools wherein for a small 
 sum each month you can not only receive their courses of 
 instruction, but you will get their text books into the bargain. 
 As a rule these books are excellently gotten up and will be 
 of great value to you. 
 
 "For a good all-around text book on marine engineering it 
 is doubtful if you can find any better than that written by 
 Prof. W. F. Durand. He was once a sea-going engineer him- 
 self before he settled down in a college, so he knows both 
 the practical and the theoretical sides of the business. Many 
 of the best books on marine engineering are by English 
 authors, as the whole world must admit that Great Britain 
 has produced some of the ablest of engineers, particularly 
 those in the marine branch. When you get further along in 
 
EXAMINATION QUESTIONS AND ANSWERS 2IQ 
 
 your business you should each buy yourself a copy of 'Reed's 
 Engineer's Handbook.' All these books are, of course, very 
 useful to you, but you can each write your own book on the 
 subject." 
 
 "Gee ! we're no highbrows," blurted out O'Rourke. 
 
 "You don't have to be to write the kind of book I'm going 
 to tell you about. 
 
 "You should each get a good-sized blank book, made of 
 serviceable paper for writing with ink and well bound. 
 Whenever you see anything of interest in a text book or in 
 any of the engineering papers you may read, copy it down in 
 this notebook. If some older engineer tells you of a good 
 method of making any particular kind of repairs, or gives 
 you any information that you think will be valuable in the 
 future, make copious notes of them in your book. As you 
 grow older you will find that such a note book will become 
 invaluable for reference, and it will increase in value to you 
 every year that it is kept up. When you take your first ex- 
 amination write down all the questions you can remember, 
 and work them out in your notebook. Even if they are not of 
 much value to you after you have attained your license, they 
 may help some young fellow who is coming after you later on. 
 
 "When these lectures which I have given you are published 
 in book form, I am going to ask the publishers if they will 
 print in the back of the book a lot of tables and useful infor- 
 mation which every marine engineer should have handy. 
 These will include tables of areas of circles, strengths of 
 materials, temperature of steam at different pressures, weights 
 of different kinds of substances with which marine engineers 
 have to deal, etc. I will also ask them to bind with the book 
 a few blank pages, upon which you can write down any other 
 bits of information you may run across which will be of value 
 to you in your business. 
 
 "This will be my last regular talk with you boys as a class 
 
220 MC ANDREW'S FLOATING SCHOOL 
 
 in the 'Floating School/ but I will be only too glad to help 
 you with any of your problems whenever I have the oppor- 
 tunity. As it is about time for you to go on watch you had 
 better turn to. I'll keep my eye on each one of you and see 
 that you get a chance as soon as you can get your tickets." 
 
 "Chief," said Jim Pierce, who had been appointed spokes- 
 man of the class, "I cannot tell you how much all of us 
 appreciate your kindness to us. Every one of us has bene- 
 fited a great deal by the instruction you have given us, and 
 we hope to show you by what we accomplish that your labors 
 with us have not been lost. We want to ask you one parting 
 favor before the 'Floating School' is broken up, and that is if 
 you will do us the honor of going to dinner with your class 
 when we reach New York." 
 
 "That's easy," laughingly replied McAndrew, "of course I 
 will." 
 
 About ten days afterward the Tuscarora arrived in New 
 York. The boys had talked over the dinner they were to 
 have on every occasion when they came together. 
 
 O'Rourke insisted that it must be a "swell dinner," and that 
 "no ordinary West Street restaurant chuck" would go. To 
 this all very readily agreed, and it was decided that they would 
 "blow themselves in a bang-up Broadway joint," as O'Rourke 
 expressed it. 
 
 Promptly at the appointed hour the four sea toilers, arrayed 
 in their best for the occasion, and accompanied by Chief 
 McAndrew, sat down at a fashionable Broadway restaurant 
 not far from Forty-second street. They were not, of course, 
 togged out in evening clothes, as were most of the other men 
 diners, but their clean-shaven faces, stalwart forms and gen- 
 erally spick appearance made them a very presentable group. 
 O'Rourke had elected himself as master of ceremonies, but 
 he was somewhat taken aback when the polite head waiter 
 handed him several bills of fare, and asked if the party would 
 
EXAMINATION QUESTIONS AND ANSWERS 221 
 
 be served a la carte or table d'hote. After getting his breath 
 he replied : 
 
 "Aw, cut out that frog-eater's chatter and give us the best 
 chow you've got in the joint." 
 
 McAndrew came to the waiter's rescue, and told him to 
 serve the dinners table d'hote, afterwards explaining to his 
 hosts that that meant they would have to pay only $1.50 each 
 for the dinner, and that they would get a very good meal for 
 less than it would cost them on the other plan. 
 
 What the boys lacked in style they made up in robust appe- 
 tites, so as each course was served it was quickly disposed 
 of with a noticeable lack of the usual picking and faultfinding 
 indulged in by the habitues of such places. True, there was 
 somewhat of a mix-up In the use of a multiplicity of knives, 
 forks and spoons placed at each plate, but each was made to 
 serve a good purpose, even if Schmidt did try to eat his fish 
 course with a combined fork and spoon usually reserved for 
 the ice cream. 
 
 The menu was printed in French, which caused much specu- 
 lation as to the composition of the next course, and some 
 grave doubts as to the course under consideration at the time. 
 
 O'Rourke had looked forward with great expectation to the 
 viand described as "pommes de terre au naturel," and could 
 not refrain from venting his disappointment when they were 
 served, by shouting out, "Gee ! they're nothing but plain old 
 boiled spuds with some grass on them." 
 
 When the "cafe demi-tasse" was served at the conclusion of 
 the meal, he nearly precipitated a small riot by demanding in 
 loud tones that he be given "a man's size cup of coffee." 
 
 However, the influence of the good dinner soon calmed his 
 ruffled temper, and when the real Havanas, not Savannahs, as 
 O'Rourke announced he had been accustomed to smoking, 
 were lighted, all was serene at the table. 
 
 Drawing a small package from his pocket, Pierce, in a few 
 
222 MC ANDREWS FLOATING SCHOOL 
 
 well-chosen and heartfelt words, presented it to McAndrew. 
 Upon opening the package, McAndrew found, to his complete 
 surprise, that it contained a handsome gold watch and chain. 
 Upon the back of the watch was neatly engraved the fol- 
 lowing : 
 
 "To Chief Engineer James Donald McAndrew, with the 
 highest esteem and gratitude of his pupils in the 'Floating 
 School.' " 
 
 Quite overcome with this evidence of his pupils' apprecia- 
 tion of his efforts, McAndrew cleared his throat and said : 
 
 "Boys, what I have done for you was not with the hope of 
 getting any such handsome reward as this, but from the 
 interest which I take in young men who are anxious to ad- 
 vance themselves in their life work. Each one of you has the 
 making of a good engineer in you, and I wish for you all 
 every success in your efforts to advance. If my instructions 
 serve to help you in accomplishing the first steps in your ad- 
 vancement I shall feel more than repaid. When you get 
 further along, and want to try for higher grades of licenses, 
 I shall, if you desire, and if conditions are such that we can 
 all be together again, be only too glad to try to aid you in the 
 same manner that I have attempted to do with the 'Floating 
 School.' " 
 
 "We'll have to call it the 'Floating High School/" re- 
 sponded O'Rourke, who was bound to have the last word. 
 
 THE END 
 
Useful Tables for Marine 
 Engineers 
 
224 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 Properties of Saturated Steam. 
 
 (Condensed from Marks and Davis's Steam Tables and Diagrams, 1909, 
 by permission of the publishers, Longmans, Green & Co.) 
 
 m 
 
 f 
 
 
 Total Heat 
 
 5i 
 
 3* 
 
 . 
 
 0> 
 
 a 
 
 
 
 B"! 
 
 
 above 32 F . 
 
 j 
 
 
 
 OH] 
 
 3 
 
 | 
 
 C 3 
 *"^ o 
 
 cc 
 
 'S 
 
 v o3 
 
 S 
 
 gW 
 
 s -a 
 
 II 
 
 8 
 
 5 
 
 |a 
 
 % a 
 
 
 II 
 
 1-1 
 
 1*1 
 
 , o5 
 
 gto.-2 
 * a 
 
 oT_ S 
 
 *! 
 
 l! 
 
 n 
 
 li 
 
 11 
 
 c3 
 
 JH 
 
 Bfe 
 
 2 1 
 
 3 g 
 
 
 f.SaQ 
 
 i_ 
 
 " 
 
 a 
 
 *" 
 
 
 H 
 
 a W 
 
 hH W 
 
 H 
 
 > 
 
 *~ 
 
 H 
 
 W 
 
 29.74 
 
 0.0886 
 
 32 
 
 0.00 
 
 1073.4 
 
 1073.4 
 
 3294 
 
 0.000304 
 
 0.0000 
 
 .1832 
 
 29.67 
 
 0.1217 
 
 40 
 
 8.05 
 
 1076.9 
 
 1068.9 
 
 2438 
 
 0.000410 
 
 0.0162 
 
 .1394 
 
 29.56 
 
 0.1780 
 
 50 
 
 18.08 
 
 1081.4 
 
 1063.3 
 
 1702 
 
 0.000587 
 
 0.0361 
 
 .0865 
 
 29.40 
 
 0.2552 
 
 60 
 
 28.08 
 
 1085.9 
 
 1057.8 
 
 1208 
 
 0.000828 
 
 0.0555 
 
 .0358 
 
 29.18 
 
 0.3626 
 
 70 
 
 38.06 
 
 1090.3 
 
 1052.3 
 
 871 
 
 0.001148 
 
 0.0745 
 
 .9868 
 
 28.09 
 
 0.505 
 
 80 
 
 48.03 
 
 1094.8 
 
 1046.7 
 
 636.8 
 
 0.001570 
 
 0.0932 
 
 .9398 
 
 28.50 
 
 0.696 
 
 90 
 
 58.00 
 
 1099.2 
 
 1041.2 
 
 469.3 
 
 0.002131 
 
 0.1114 
 
 .8944 
 
 28.00 
 
 0.946 
 
 100 
 
 67.97 
 
 1103.6 
 
 1035.6 
 
 350.8 
 
 0.002851 
 
 0.1295 
 
 .8505 
 
 27.83 
 
 1 
 
 101.83 
 
 69.8 
 
 1104.4 
 
 1034.6 
 
 333.0 
 
 0.00300 
 
 0.1327 
 
 .8427 
 
 25.85 
 
 2 
 
 126.15 
 
 94.0 
 
 1115.0 
 
 1021.0 
 
 173.5 
 
 0.00576 
 
 0.1749 
 
 .7431 
 
 23.81 
 
 3 
 
 141.52 
 
 109.4 
 
 1121.6 
 
 1012.3 
 
 118.5 
 
 0.00845 
 
 0.2008 
 
 .6840 
 
 21.78 
 
 4 
 
 153.01 
 
 120.9 
 
 1126.5 
 
 1005.7 
 
 90.5 
 
 0.01107 
 
 0.2198 
 
 .6416 
 
 19.74 
 
 5 
 
 162.28 
 
 130.1 
 
 1130.5 
 
 1030.3 
 
 73.33 
 
 0.01364 
 
 0.2348 
 
 .6084 
 
 17.70 
 
 6 
 
 170.06 
 
 137.9 
 
 1133.7 
 
 995.8 
 
 61.89 
 
 01616 
 
 0.2471 
 
 .5814 
 
 15.67 
 
 7 
 
 176.85 
 
 144.7 
 
 1136.5 
 
 991.8 
 
 53.56 
 
 0.01867 
 
 0.2579 
 
 .5582 
 
 13.63 
 
 8 
 
 182.86 
 
 150.8 
 
 1139.0 
 
 938.2 
 
 47.27 
 
 0.02115 
 
 0.2673 
 
 .5380 
 
 11.60 
 
 9 
 
 188.27 
 
 156.2 
 
 1141.1 
 
 985.0 
 
 42.36 
 
 0.02361 
 
 0.2756 
 
 .5202 
 
 9.56 
 
 10 
 
 193.22 
 
 161.1 
 
 1143.1 
 
 982.0 
 
 38.38 
 
 0.02606 
 
 0.2832 
 
 .5042 
 
 7.52 
 
 11 
 
 197.75 
 
 165.7 
 
 1144.9 
 
 979.2 
 
 35.10 
 
 0.02849 
 
 0.2902 
 
 .4895 
 
 5.49 
 
 12 
 
 201 .96 
 
 169.9 
 
 1146.5 
 
 976.6 
 
 32.36 
 
 0.03090 
 
 0.2967 
 
 .4760 
 
 3.45 
 
 13 
 
 205.87 
 
 173.8 
 
 1148.0 
 
 974.2 
 
 30.03 
 
 0.03330 
 
 0.3025 
 
 .4639 
 
 1.42 
 
 14 
 
 209.55 
 
 177.5 
 
 1149.4 
 
 971.9 
 
 28.02 
 
 0.03569 
 
 0.3081 
 
 .4523 
 
 Ibs. 
 
 
 
 
 
 
 
 
 
 
 gage. 
 
 14.70 
 
 212 
 
 180.0 
 
 1150.4 
 
 970.4 
 
 26.79 
 
 0.03732 
 
 0.3118 
 
 .4447 
 
 03 
 
 15 
 
 213.0 
 
 181.0 
 
 1150.7 
 
 969.7 
 
 26.27 
 
 0.03806 
 
 0.3133 
 
 .4416 
 
 1.3 
 
 16 
 
 216.3 
 
 184.4 
 
 1152.0 
 
 967.6 
 
 24.79 
 
 0.04042 
 
 0.3183 
 
 .4311 
 
 2.3 
 
 17 
 
 219.4 
 
 187.5 
 
 1153.1 
 
 965.6 
 
 23.38 
 
 0.04277 
 
 0.3229 
 
 .4215 
 
 3.3 
 
 18 
 
 222.4 
 
 190.5 
 
 1154.2 
 
 963.7 
 
 22.16 
 
 0.04512 
 
 0.3273 
 
 .4127 
 
 4.3 
 
 19 
 
 225.2 
 
 193.4 
 
 1155.2 
 
 961.8 
 
 21.07 
 
 0.04746 
 
 0.3315 
 
 .4045 
 
 5.3 
 
 20 
 
 228.0 
 
 196.1 
 
 1156.2 
 
 960.0 
 
 20.08 
 
 0.049) 
 
 0.3355 
 
 .3965 
 
 6.3 
 
 21 
 
 230.6 
 
 198.8 
 
 1157.1 
 
 958.3 
 
 19.18 
 
 0.05213 
 
 0.3393 
 
 .3887 
 
 7.3 
 
 22 
 
 233.1 
 
 201.3 
 
 1158.0 
 
 956.7 
 
 18.37 
 
 0.05445 
 
 0.3430 
 
 .3811 
 
 8.3 
 
 23 
 
 235.5 
 
 203.8 
 
 1158.8 
 
 955.1 
 
 17.62 
 
 0.05676 
 
 0.3465 
 
 .3739 
 
 9.3 
 
 24 
 
 237.8 
 
 205.1 
 
 1159.6 
 
 953.5 
 
 16.93 
 
 0.05907 
 
 0.3499 
 
 .3670 
 
 10.3 
 
 25 
 
 240.1 
 
 208.4 
 
 1160.4 
 
 952.0 
 
 16.30 
 
 0.0614 
 
 0.3532 
 
 1.3604 
 
 11.3 
 
 25 
 
 242.2 
 
 210 6 
 
 1161.2 
 
 950.. 6 
 
 15.72 
 
 0.0636 
 
 0.3564 
 
 1 .3542 
 
 12.3 
 
 27 
 
 244.4 
 
 212.7 
 
 1161.9 
 
 949.2 
 
 15.18 
 
 0.0659 
 
 0.3594 
 
 1.3483 
 
 13.3 
 
 23 
 
 246.4 
 
 214.8 
 
 1162.6 
 
 947.8 
 
 14.67 
 
 0.0682 
 
 0.3623 
 
 1.3425 
 
 14.3 
 
 29 
 
 248.4 
 
 216.8 
 
 1163.2 
 
 946.4 
 
 14.19 
 
 0.0705 
 
 0.3652 
 
 1 .3367 
 
 15.3 
 
 30 
 
 250.3 
 
 218.8 
 
 1163.9 
 
 945.1 
 
 13.74 
 
 0.0728 
 
 0.3680 
 
 1.3311 
 
 15.3 
 
 31 
 
 252.2 
 
 220.7 
 
 1164.5 
 
 943.8 
 
 13.32 
 
 0.0751 
 
 0.3707 
 
 1.3257 
 
 17.3 
 
 32 
 
 254.1 
 
 222.6 
 
 1165.1 
 
 942.5 
 
 12.93 
 
 0.0773 
 
 0.3733 
 
 1.3205 
 
 18.3 
 
 33 
 
 255.8 
 
 224.4 
 
 1165.7 
 
 941.3 
 
 12.57 
 
 0.0795 
 
 0.3759 
 
 .3155 
 
 19.3 
 
 34 
 
 257.6 
 
 225.2 
 
 1166.3 
 
 940.1 
 
 12.22 
 
 0.0818 
 
 0.3784 
 
 .3107 
 
 20.3 
 
 35 
 
 259.3 
 
 |27.9 
 
 1166.8 
 
 938.9 
 
 11.89 
 
 0.0841 
 
 0.3808 
 
 .3060 
 
 21.3 
 
 36 
 
 261,0 
 
 
 1167.3 
 
 937.7 
 
 11.58 
 
 0.0863 
 
 0.3832 
 
 .3014 
 
 22.3 
 
 37 
 
 262.6 
 
 231 '.3 
 
 1167.8 
 
 936.6 
 
 11.29 
 
 ).0886 
 
 0.3855 
 
 .2969 
 
 23.3 
 
 38 
 
 264.2 
 
 232.9 
 
 1168.4 
 
 935.5 
 
 11.01 
 
 0.0908 
 
 < 877 
 
 .2925 
 
 24.3 
 
 39 
 
 265.8 
 
 234.5 
 
 1168.9 
 
 934.4 
 
 10.74 
 
 0.0931 
 
 03899 
 
 .2882 
 
 25.3 
 
 40 
 
 267.3 
 
 236.1 
 
 1169.4 
 
 933.3 
 
 10.49 
 
 0.0953 
 
 0.3920 
 
 .28^1 
 
 25.3 
 
 41 
 
 268.7 
 
 237.6 
 
 1169.8 
 
 932.2 
 
 10.25 
 
 0.0976 
 
 0.3941 
 
 .2800 
 
 Republished by permission of Messrs. John Wiley & Sons, Inc. 
 from Kent's Mechanical Engineers Pocket- Book. 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 Properties of Saturated Steam. (Continued.) 
 
 225 
 
 fa 
 
 e 
 
 
 Total Heat 
 
 ^ 
 
 
 
 ~ 
 
 T 
 
 3T- 
 
 I c- 
 
 . . 
 
 above 32 F. 
 
 fl 
 
 "3 
 
 -- 
 
 6*3 
 
 3 
 
 5 
 
 IOQ 
 
 1" 
 
 || 
 
 
 
 1 -2 
 
 IS 
 
 6- 
 
 -" 
 
 "8 
 
 Sc 
 
 K 
 
 o> a 
 
 ng 
 
 p 
 
 "3 'c 
 
 2*3 
 
 5 S 
 
 1*3 
 
 I ^ 
 
 tl 
 
 i 
 
 fc 
 
 S3 
 
 il 
 
 3 
 
 1 
 
 H^ 
 
 2 M 
 
 c K 
 
 J 
 
 i>~ 
 
 ^ 
 
 W 
 
 i 
 
 27.3 
 
 42 
 
 270.2 
 
 239.1 
 
 1170.3 
 
 931.2 
 
 10.02 
 
 0.0998 
 
 3962 
 
 2759 
 
 23.3 
 
 43 
 
 271.7 
 
 240.5 
 
 1170.7 
 
 933.2 
 
 9.80 
 
 0.1020 
 
 0.3982 
 
 2720 
 
 29 3 
 
 44 
 
 273.1 
 
 242.0 
 
 1171.2 
 
 929.2 
 
 9.59 
 
 0.1043 
 
 0.4002 
 
 2681 
 
 33.3 
 
 45 
 
 274.5 
 
 243.4 
 
 1171.6 
 
 923.2 
 
 9.39 
 
 0.1065 
 
 4021 
 
 .2644 
 
 31.3 
 
 46 
 
 275.8 
 
 244.8 
 
 1172.0 
 
 927.2 
 
 9.20 
 
 0.1087 
 
 0.4040 
 
 2607 
 
 32.3 
 
 47 
 
 277.2 
 
 246.1 
 
 1172.4 
 
 926.3 
 
 9.02 
 
 0.1109 
 
 0.4059 
 
 2571 
 
 33.3 
 
 43 
 
 278 5 
 
 247.5 
 
 1172 8 
 
 925.3 
 
 8.84 
 
 0.1131 
 
 ^V)77 
 
 2336 
 
 34.3 
 
 49 
 
 279.8 
 
 243.8 
 
 1173.2 
 
 924.4 
 
 8 67 
 
 0.1153 
 
 0^4095 
 
 '2502 
 
 33.3 
 
 50 
 
 281.0 
 
 250.1 
 
 1173.6 
 
 923.5 
 
 8.51 
 
 0.1175 
 
 0.4113 
 
 2468 
 
 35.3 
 
 51 
 
 282.3 
 
 251.4 
 
 1174.0 
 
 922.6 
 
 8.35 
 
 0.1197 
 
 4130 
 
 2432 
 
 37.3 
 
 52 
 
 283.5 
 
 252.6 
 
 1174.3 
 
 921.7 
 
 8.20 
 
 0.1219 
 
 0.4147 
 
 '2405 
 
 33.3 
 
 53 
 
 284 7 
 
 253.9 
 
 1174.7 
 
 920.8 
 
 8.05 
 
 0.1241 
 
 0.4164 
 
 2370 
 
 39.3 
 
 54 
 
 285.9 
 
 255.1 
 
 1175.0 
 
 919.9 
 
 7.91 
 
 0.1263 
 
 0.4180 
 
 .2339 
 
 40.3 
 
 55 
 
 237.1 
 
 255.3 
 
 1175.4 
 
 919.0 
 
 7.73 
 
 0.1285 
 
 0.4196 
 
 2309 
 
 41.3 
 
 56 
 
 238.2 
 
 257.5 
 
 1175.7 
 
 918.2 
 
 7.65 
 
 0.1307 
 
 0.4212 
 
 2278 
 
 42.3 
 
 57 
 
 239.4 
 
 258.7 
 
 1176.0 
 
 917.4 
 
 7.52 
 
 0.1329 
 
 0.4227 
 
 .2248 
 
 43.3 
 
 58 
 
 290.5 
 
 259.8 
 
 1176.4 
 
 916.5 
 
 7.40 
 
 1350 
 
 0.4242 
 
 .2218 
 
 44.3 
 
 59 
 
 291.6 
 
 261.0 
 
 1176.7 
 
 915.7 
 
 7.23 
 
 0.1372 
 
 0.4257 
 
 2189 
 
 45.3 
 
 60 
 
 292.7 
 
 262.1 
 
 1177.0 
 
 914.9 
 
 7.17 
 
 0.1394 
 
 0.4272 
 
 .2160 
 
 45.3 
 
 61 
 
 293.8 
 
 263.2 
 
 1177.3 
 
 914.1 
 
 7.05 
 
 0.1416 
 
 0.4287 
 
 .2132 
 
 47.3 
 
 62 
 
 294.9 
 
 254.3 
 
 1177.6 
 
 913.3 
 
 6.93 
 
 0.1438 
 
 0.4302 
 
 2104 
 
 43.3 
 
 63 
 
 295.9 
 
 265.4 
 
 1177.9 
 
 912.5 
 
 6.85 
 
 0.1450 
 
 0.4316 
 
 .2077 
 
 49.3 
 
 64 
 
 297.0 
 
 256.4 
 
 1178.2 
 
 911.8 
 
 6.75 
 
 0.1482 
 
 0.4330 
 
 .2050 
 
 50.3 
 
 65 
 
 293.0 
 
 257.5 
 
 1178.5 
 
 911.0 
 
 6.65 
 
 0.1503 
 
 0.4344 
 
 2024 
 
 51.3 
 
 66 
 
 299.0 
 
 253.5 
 
 1178.8 
 
 910.2 
 
 6.56 
 
 0.1525 
 
 0.4358 
 
 1998 
 
 52.3 67 
 
 303.0 
 
 259.6 
 
 1179.0 
 
 909.5 
 
 6.47 
 
 0.1547 
 
 0.4371 
 
 .1972 
 
 53.3 
 
 68 
 
 301.0 
 
 270.6 
 
 1179.3 
 
 933.7 
 
 6.38 
 
 0.1569 
 
 0.4385 
 
 .1946 
 
 54.3 
 
 69 
 
 302.0 
 
 271.6 
 
 1179.6 
 
 933.0 
 
 6.29 
 
 0.1590 
 
 0.4398 
 
 1921 
 
 55.3 
 
 70 
 
 302.9 
 
 272.6 
 
 1179.8 
 
 937.2 
 
 6 20 
 
 0.1612 
 
 0.4411 
 
 .1896 
 
 56.3 
 
 71 
 
 303.9 
 
 273.6 
 
 1180.1 
 
 935.5 
 
 6.12 
 
 0.1634 
 
 0.4424 
 
 .1872 
 
 57.3 
 
 72 
 
 304.8 
 
 274.5 
 
 1133.4 
 
 903.8 
 
 6.04 
 
 0.1656 
 
 0.4437 
 
 .1848 
 
 58.3 
 
 73 
 
 305.8 
 
 275.5 
 
 1130. 6 
 
 905.1 
 
 5.95 
 
 0.1678 
 
 0.4449 
 
 .1825 
 
 59.3 
 
 74 
 
 306.7 
 
 276.5 
 
 1133.9 
 
 904.4 
 
 5.89 
 
 0.1699 
 
 0.4462 
 
 .1801 
 
 60.3 
 
 75 
 
 307.6 
 
 277.4 
 
 1181.1 
 
 903.7 
 
 5.81 
 
 0.1721 
 
 0.4474 
 
 .1778 
 
 61.3 
 
 76 
 
 303.5 
 
 273.3 
 
 1181.4 
 
 903.0 
 
 5.74 
 
 0.1743 
 
 0.4487 
 
 .1755 
 
 62.3 
 
 77 
 
 309.4 
 
 279.3 
 
 1181. 6 
 
 902.3 
 
 5.67 
 
 0.1764 
 
 0.4499 
 
 .1730 
 
 63.3 
 
 73 
 
 310.3 
 
 280.2 
 
 1181.8 
 
 901.7 
 
 5.60 
 
 0.1785 
 
 0.4511 
 
 .1712 
 
 64.3 
 
 79 
 
 311.2 
 
 231.1 
 
 1182.1 
 
 901.0 
 
 5.54 
 
 0.1803 
 
 0.4523 
 
 .1687 
 
 65.3 
 
 80 
 
 312.0 
 
 232.0 
 
 1182.3 
 
 933.3 
 
 5.47 
 
 0.1829 
 
 0.4535 
 
 .1665 
 
 66.3 
 
 81 
 
 312.9 
 
 232.9 
 
 1182.5 
 
 899.7 
 
 5.41 
 
 0.1851 
 
 0.4546 
 
 .1644 
 
 67.3 
 
 82 
 
 313.8 
 
 233.8 
 
 1182.8 
 
 899.0 
 
 5.34 
 
 0.1873 
 
 0.4557 
 
 .1623 
 
 68.3 
 
 83 
 
 314.6 
 
 284.6 
 
 1133.0 
 
 893.4 
 
 5.28 
 
 0.1894 
 
 0.4568 
 
 .1602 
 
 69.3 
 
 84 
 
 315.4 
 
 283.5 
 
 1183.2 
 
 897.7 
 
 5.22 
 
 0.1915 
 
 0.4579 
 
 .1581 
 
 70.3 
 
 85 
 
 316.3 
 
 285.3 
 
 1183.4 
 
 897.1 
 
 5.16 
 
 0.1937 
 
 0.4590 
 
 1561 
 
 71.3 
 
 86 
 
 317.1 
 
 237.2 
 
 1183.6 
 
 895.4 
 
 5.10 
 
 1959 
 
 0.4601 
 
 1540 
 
 72.3 
 
 87 
 
 317.9 
 
 283.0 
 
 1183.8 
 
 895.8 
 
 5.05 
 
 0.1980 
 
 0.4612 
 
 1520 
 
 73.3 
 
 88 
 
 318.7 
 
 283.9 
 
 1 184.0 
 
 895.2 
 
 5 00 
 
 0.2001 
 
 0.4623 
 
 .1500 
 
 74.3 
 
 89 
 
 319.5 
 
 239.7 
 
 1184.2 
 
 894.6 
 
 4.94 
 
 0.2023 
 
 0.4633 
 
 1481 
 
 75.3 
 
 90 
 
 320.3 
 
 290.5 
 
 1184.4 
 
 893.9 
 
 4.89 
 
 0.2044 
 
 0.4644 
 
 1461 
 
 76.3 
 
 91 
 
 321.1 
 
 291.3 
 
 1184.6 
 
 893.3 
 
 4.84 
 
 0.2065 
 
 0.4654 
 
 1442 
 
 77.3 
 
 92 
 
 321.8 
 
 292 1 
 
 1184.8 
 
 892.7 
 
 4.79 
 
 0.2087 
 
 0.4664 
 
 1423 
 
 73.3 
 
 93 
 
 322.6 
 
 292.9 
 
 1185.0 
 
 892.1 
 
 4.74 
 
 0.2109 
 
 0.4674 
 
 1404 
 
 79.3 
 
 94 
 
 323.4 
 
 293.7 
 
 1185 2 
 
 891.5 
 
 4.69 
 
 0.2130 
 
 4584 
 
 1385 
 
 80.3 
 
 95 
 
 324.1 
 
 294.5 
 
 1185.4 
 
 890.9 
 
 4.65 
 
 0.2151 
 
 0.4694 
 
 1367 
 
226 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 Properties of Saturated Steam. (Continued.) 
 
 "- 
 
 g a 
 
 
 Total Heat 
 
 ^^ 
 
 ^ 
 
 
 cu 
 
 ft 
 
 M 
 
 13 
 
 3^ 
 
 
 above 32 F. 
 
 ^"S 
 
 fa*o 
 
 Oh-! 
 
 
 
 03 
 
 UU 1 
 
 P 
 
 II 
 
 
 |w 
 
 P.a 
 
 ~ g" 
 
 * 
 
 H 
 
 <" a 
 
 6 u 
 
 o 
 
 PH 
 
 "oj C 
 
 *- .~ 
 
 O> 'Q 
 
 te"^ 
 
 ^i-) 
 
 ! 
 
 
 *o 
 
 ft 
 
 .2 ft 
 
 t. 53 
 a 
 
 ^ P 
 
 
 +3 03 
 
 a 
 
 
 j 
 
 || 
 
 |fj 
 
 o 1 " 1 
 
 I* 
 
 H 
 
 E 
 
 * 
 
 jp 
 
 O 
 
 -O-SCQ 
 
 |e 
 
 11 
 
 W 
 
 "c o 
 
 W 
 
 81.3 
 
 96 
 
 324.9 
 
 295.3 
 
 1185.6 
 
 890.3 
 
 4.60 
 
 0.2172 
 
 0.4704 
 
 1348 
 
 82.3 
 
 97 
 
 325.6 
 
 296.1 
 
 1185.8 
 
 889.7 
 
 4.56 
 
 0.2193 
 
 0.4714 
 
 .1330 
 
 83.3 
 
 93 
 
 326.4 
 
 296.8 
 
 1185.0 
 
 689.2 
 
 4.51 
 
 0.2215 
 
 0.4724 
 
 .1312 
 
 G4.3 
 
 99 
 
 327.1 
 
 297.6 
 
 1185.2 
 
 888.6 
 
 4.47 
 
 0.2237 
 
 0.4733 
 
 .1295 
 
 85.3 
 
 100 
 
 327.8 
 
 293.3 
 
 1!36.3 
 
 888.0 
 
 4.429 
 
 0.2253 
 
 4743 
 
 .1277 
 
 87.3 
 
 102 
 
 329.3 
 
 299.8 
 
 1186.7 
 
 886.9 
 
 4.347 
 
 0.2300 
 
 0.4762 
 
 .1242 
 
 89.3 
 
 104 
 
 330.7 
 
 301.3 
 
 1187.0 
 
 885.8 
 
 4.268 
 
 0.2343 
 
 0.4780 
 
 .1208 
 
 91.3 
 
 106 
 
 332.0 
 
 302.7 
 
 1187.4 
 
 884.7 
 
 4.192 
 
 0.2335 
 
 4798 
 
 .1174 
 
 93.3 
 
 103 
 
 333.1 
 
 304.1 
 
 1187.7 
 
 883.6 
 
 4.118 
 
 0.2429 
 
 0.4816 
 
 .1141 
 
 95.3 
 
 110 
 
 334.8 
 
 305.5 
 
 1188.0 
 
 882.5 
 
 4.047 
 
 2472 
 
 0.4834 
 
 .1108 
 
 97.3 
 
 112 
 
 335.1 
 
 305.9 
 
 1 188. 4 
 
 881.4 
 
 3.978 
 
 0.2514 
 
 0.4852 
 
 .1076 
 
 99.3 
 
 114 
 
 337.4 
 
 303.3 
 
 1188.7 
 
 880.4 
 
 3.912 
 
 0.2556 
 
 0.4869 
 
 1045 
 
 UI.3 
 
 116 
 
 338.7 
 
 309.6 
 
 1189.0 
 
 879.3 
 
 3.848 
 
 0.2599 
 
 4885 
 
 .1014 
 
 103.3 
 
 118 
 
 340.0 
 
 311.0 
 
 1189.3 
 
 878.3 
 
 3.786 
 
 0.2641 
 
 0.4903 
 
 .0984 
 
 105.3 
 
 120 
 
 341.3 
 
 312.3 
 
 1189.6 
 
 877.2 
 
 3.726 
 
 2683 
 
 0.4919 
 
 0954 
 
 107.3 
 
 122 
 
 342.5 
 
 313.6 
 
 1189.8 
 
 876.2 
 
 3.668 
 
 0.2726 
 
 0.4935 
 
 .0924 
 
 109.3 
 
 124 
 
 343.8 
 
 314.9 
 
 1190.1 
 
 875.2 
 
 3.611 
 
 0.2769 
 
 0.4951 
 
 .0895 
 
 111.3 
 
 125 
 
 345.0 
 
 316.2 
 
 1190.4 
 
 874.2 
 
 3.556 
 
 0.2812 
 
 0.4967 
 
 .0865 
 
 113.3 
 
 123 
 
 346.2 
 
 317.4 
 
 1190.7 
 
 873.3 
 
 3 504 
 
 0.2854 
 
 0.49.2 
 
 .0837 
 
 115.3 
 
 130 
 
 347.4 
 
 318.6 
 
 1191.0 
 
 872.3 
 
 3.452 
 
 0.2897 
 
 0.4998 
 
 .0809 
 
 117.3 
 
 132 
 
 348.5 
 
 319.9 
 
 1191.2 
 
 871.3 
 
 3.402 
 
 0.2939 
 
 0.5013 
 
 .0782 
 
 119.3 
 
 134 
 
 349.7 
 
 321. 1 
 
 1191.5 
 
 870.4 
 
 3.354 
 
 0.2981 
 
 0.5028 
 
 .0755 
 
 121.3 
 
 136 
 
 350.8 
 
 322.3 
 
 1191.7 
 
 869.4 
 
 3.308 
 
 3023 
 
 0.5043 
 
 .0728 
 
 123.3 
 
 138 
 
 352.0 
 
 323.4 
 
 1192.0 
 
 868.5 
 
 3.263 
 
 0.3065 
 
 5057 
 
 .0702 
 
 125.3 
 
 149 
 
 353.1 
 
 324.6 
 
 1192.2 
 
 867.6 
 
 3.219 
 
 0.3107 
 
 0.5072 
 
 .0675 
 
 127.3 
 
 142 
 
 354.2 
 
 325.8 
 
 1192.5 
 
 866.7 
 
 3.175 
 
 0.3150 
 
 0.5086 
 
 .0649 
 
 129.3 
 
 144 
 
 355.3 
 
 326.9 
 
 1192.7 
 
 865.8 
 
 3.133 
 
 0.3192 
 
 0.5100 
 
 .0624 
 
 131 3 
 
 145 
 
 355.3 
 
 328.0 
 
 1192.9 
 
 864.9 
 
 3.092 
 
 0.3234 
 
 0.5114 
 
 .0599 
 
 133.3 
 
 143 
 
 357.4 
 
 329.1 
 
 1193.2 
 
 864.0 
 
 3.052 
 
 3276 
 
 0.5128 
 
 .0574 
 
 135.3 
 
 150 
 
 358.5 
 
 330.2 
 
 1193.4 
 
 863.2 
 
 3 012 
 
 0.3320 
 
 0.5142 
 
 .0550 
 
 137.3 
 
 152 
 
 359.5 
 
 331.4 
 
 1193.6 
 
 862.3 
 
 2.974 
 
 0.3362 
 
 0.5155 
 
 .0525 
 
 139.3 
 
 154 
 
 350.5 
 
 332.4 
 
 1193.8 
 
 861.4 
 
 2.938 
 
 3404 
 
 0.5169 
 
 .0501 
 
 141.3 
 
 156 
 
 3o1.6 
 
 333.5 
 
 1194.1 
 
 860.6 
 
 2.902 
 
 0.3446 
 
 0.5182 
 
 .0477 
 
 143.3 
 
 158 
 
 352.6 
 
 334.6 
 
 1194.3 
 
 859.7 
 
 2.868 
 
 3488 
 
 0.5195 
 
 .0454 
 
 145.3 
 
 160 
 
 363.6 
 
 335.6 
 
 1194.5 
 
 858.8 
 
 2.834 
 
 0.3529 
 
 0.5208 
 
 .0431 
 
 147.3 
 
 162 
 
 364.6 
 
 336.7 
 
 1194.7 
 
 858.0 
 
 2.801 
 
 0.3570 
 
 0.5220 
 
 .0409 
 
 149.3 
 
 164 
 
 365.6 
 
 337.7 
 
 1194.9 
 
 857.2 
 
 2.769 
 
 0.3612 
 
 0.5233 
 
 .0387 
 
 151.3 
 
 166 
 
 365.5 
 
 338.7 
 
 1195.1 
 
 856.4 
 
 2.737 
 
 0.3654 
 
 5245 
 
 .0365 
 
 153.3 
 
 168 
 
 357.5 
 
 339.7 
 
 1195.3 
 
 855.5 
 
 2.706 
 
 3696 
 
 0.5257 
 
 .0343 
 
 155.3 
 
 170 
 
 358.5 
 
 340.7 
 
 1195.4 
 
 854.7 
 
 2.675 
 
 0.3738 
 
 0.5269 
 
 0321 
 
 157.3 
 
 172 
 
 359.4 
 
 341.7 
 
 1195.6 
 
 853.9 
 
 2.645 
 
 3780 
 
 0.5281 
 
 .0300 
 
 159.3 
 
 174 
 
 370.4 
 
 342.7 
 
 1195.8 
 
 853.1 
 
 2.616 
 
 0.3822 
 
 0.5293 
 
 0278 
 
 161.3 
 
 175 
 
 371.3 
 
 343.7 
 
 11%. 
 
 852.3 
 
 2.588 
 
 0.3864 
 
 5305 
 
 0257 
 
 153.3 
 
 173 
 
 372.2 
 
 344.7 
 
 1196.2 
 
 851.5 
 
 2 560 
 
 3906 
 
 0.5317 
 
 .0235 
 
 165 3 
 
 180 
 
 373.1 
 
 345.6 
 
 1196.4 
 
 850.8 
 
 2.533 
 
 0.3948 
 
 0.5328 
 
 .0215 
 
 167.3 
 
 182 
 
 374.0 
 
 346.6 
 
 1195.6 
 
 850.0 
 
 2.507 
 
 0.3989 
 
 0.5339 
 
 .0195 
 
 159.3 
 
 184 
 
 374.9 
 
 347.6 
 
 1195.8 
 
 849.2 
 
 2.481 
 
 0.4031 
 
 0.5351 
 
 .0174 
 
 171.3 
 
 186 
 
 375.8 
 
 348.5 
 
 1196.9 
 
 848.4 
 
 2.455 
 
 0.4073 
 
 0.5362 
 
 0154 
 
 173.3 
 
 183 
 
 376.7 
 
 349.4 
 
 1197.1 
 
 847.7 
 
 2.430 
 
 0.4115 
 
 0.5373 
 
 .0134 
 
 175 3 
 
 190 
 
 377.6 
 
 350.4 
 
 1197.3 
 
 846.9 
 
 2.406 
 
 0.4157 
 
 5384 
 
 .0114 
 
 177.3 
 
 192 
 
 378.5 
 
 351.3 
 
 1197.4 
 
 846.1 
 
 2.381 
 
 0.4199 
 
 0.5395 
 
 .0095 
 
 179.3 
 
 194 
 
 379.3 
 
 352.2 
 
 1197.6 
 
 845.4 
 
 2.358 
 
 0.4241 
 
 0.5405 
 
 .0076 
 
 181 3 
 
 196 
 
 380.2 
 
 353.1 
 
 1197.8 
 
 844.7 
 
 2.335 
 
 0.4283 
 
 0.5416 
 
 .0056 
 
 183.3 
 
 198 
 
 381.0 
 
 354.0 
 
 1197.9 
 
 843.9 
 
 2.312 
 
 0.4325 
 
 0.5426 
 
 .0038 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 Properties of Saturated Steam. (Continued.) 
 
 227 
 
 af 
 
 2" a 
 
 
 Total Heat 
 
 - , 
 
 
 
 O 
 
 , 
 
 3M 
 
 
 
 above32F. 
 
 .J 
 
 -8 
 
 0^ 
 
 J3 
 
 jg 
 
 If 
 
 |f 
 
 il 
 
 I 
 
 i * 
 
 |f 
 
 o*3 
 
 si 
 
 8 
 
 "8 . 
 
 
 || 
 
 II 
 
 H 
 
 o^ j> 
 
 1*1 
 
 af _ g 
 
 i 
 
 II 
 
 H 
 
 2^9 
 
 
 S ~~~ 
 
 -*J ^ 
 
 ^ o 
 
 *-* 11 ^ 
 
 |.sl 
 
 
 "c ^ 
 
 "c o 
 
 o 
 
 < 
 
 H 
 
 HH * 
 
 5 s 
 
 h-) 
 
 
 ^ 
 
 w 
 
 w 
 
 185.3 
 
 200 
 
 381.9 
 
 354.9 
 
 1198.1 
 
 843.2 
 
 2.290 
 
 0.437 
 
 5437 
 
 1.0019 
 
 190.3 
 
 205 
 
 384.0 
 
 357.1 
 
 1198.5 
 
 841.4 
 
 2.237 
 
 0.447 
 
 0.5463 
 
 0.9973 
 
 195 3 
 
 210 
 
 386.0 
 
 359.2 
 
 1198.8 
 
 839.6 
 
 2.187 
 
 0.457 
 
 5488 
 
 9928 
 
 200.3 
 
 215 
 
 388.0 
 
 361.4 
 
 1 199. 2 
 
 837.9 
 
 2.138 
 
 0.468 
 
 0.5513 
 
 0.9885 
 
 205.3 
 
 220 
 
 389.9 
 
 363.4 
 
 1199.6 
 
 836.2 
 
 2 091 
 
 0.478 
 
 0.5538 
 
 0.9841 
 
 210.3 
 
 225 
 
 391.9 
 
 365.5 
 
 1199.9 
 
 834.4 
 
 2.046 
 
 0.489 
 
 0.5562 
 
 9799 
 
 215.3- 
 
 230 
 
 393.8 
 
 367.5 
 
 1200.2 
 
 832.8 
 
 2.004 
 
 0.499 
 
 5586 
 
 0.9758 
 
 220.3 
 
 235 
 
 395.6 
 
 369.4 
 
 1200.6 
 
 831.1 
 
 I 964 
 
 0.509 
 
 0.5610 
 
 0.9717 
 
 225.3 
 
 240 
 
 397.4 
 
 371.4 
 
 1200.9 
 
 829.5 
 
 1.924 
 
 0.520 
 
 0.5633 
 
 0.9676 
 
 230.3 
 
 245 
 
 399.3 
 
 373.3 
 
 1201.2 
 
 827.9 
 
 1.887 
 
 0.530 
 
 0.5655 
 
 9638 
 
 235.3 
 
 250 
 
 401.1 
 
 375.2 
 
 1201.5 
 
 825.3 
 
 1.850 
 
 0.541 
 
 0.5676 
 
 0.9600 
 
 245.3 
 
 260 
 
 404.5 
 
 378.9 
 
 1202.1 
 
 823.1 
 
 1 782 
 
 0.561 
 
 5719 
 
 0.9525 
 
 255.3 
 
 270 
 
 407.9 
 
 382.5 
 
 1202.6 
 
 820.1 
 
 1.718 
 
 582 
 
 0.5760 
 
 9454 
 
 255.3 
 
 280 
 
 411. 2 
 
 385.0 
 
 1203.1 
 
 817.1 
 
 1 658 
 
 0.603 
 
 0.5800 
 
 0.9385 
 
 275.3 
 
 290 
 
 414.4 
 
 389.4 
 
 1203.6 
 
 814.2 
 
 1.602 
 
 0.624 
 
 0.5840 
 
 9316 
 
 285.3 
 
 300 
 
 417.5 
 
 392.7 
 
 1204.1 
 
 811.3 
 
 1.551 
 
 0.645 
 
 0.5878 
 
 0.9251 
 
 295.3 
 
 310 
 
 420.5 
 
 395.9 
 
 1204.5 
 
 808.5 
 
 1.502 
 
 0.666 
 
 5915 
 
 9187 
 
 305.3 
 
 320 
 
 423.4 
 
 399.1 
 
 1204.9 
 
 805.8 
 
 1.456 
 
 687 
 
 0.5951 
 
 0.9125 
 
 315.3 
 
 330 
 
 425.3 
 
 402.2 
 
 1205.3 
 
 803.1 
 
 1.413 
 
 0.708 
 
 5986 
 
 0.9065 
 
 325.3 
 
 340 
 
 429.1 
 
 405.3 
 
 1205.7 
 
 800.4 
 
 1.372 
 
 729 
 
 0.6020 
 
 9005 
 
 335.3 
 
 350 
 
 431.9 
 
 408.2 
 
 1205.1 
 
 797.8 
 
 1 334 
 
 0.750 
 
 0.6053 
 
 0.8949 
 
 345.3 
 
 360 
 
 434.6 
 
 411.2 
 
 1205.4 
 
 795.3 
 
 1.298 
 
 0.770 
 
 0.6085 
 
 8894 
 
 355.3 
 
 370 
 
 437.2 
 
 414.0 
 
 1205.8 
 
 792.8 
 
 1.264 
 
 0.791 
 
 0.6116 
 
 0.8840 
 
 355.3 
 
 380 
 
 439.8 
 
 416.8 
 
 1207.1 
 
 790.3 
 
 1.231 
 
 0.812 
 
 6147 
 
 0.8788 
 
 375.3 
 
 390 
 
 442.3 
 
 419.5 
 
 1207.4 
 
 787.9 
 
 1.200 
 
 0.833 
 
 0.6178 
 
 0.8737 
 
 385.3 
 
 400 
 
 444.8 
 
 422 
 
 1203 
 
 786 
 
 1.17 
 
 0.86 
 
 0.621 
 
 0.868 
 
 435.3 
 
 450 
 
 456.5 
 
 435 
 
 1209 
 
 774 
 
 1.04 
 
 0.96 
 
 0.635 
 
 0.844 
 
 485.3 
 
 500 
 
 467.3 
 
 448 
 
 1210 
 
 762 
 
 0.93 
 
 1.08 
 
 0.648 
 
 0.822 
 
 535.3 
 
 550 
 
 477.3 
 
 459 
 
 1210 
 
 751 
 
 0.83 
 
 1.20 
 
 0.659 
 
 0.801 
 
 585.3 
 
 600 
 
 485.6 
 
 459 
 
 1210 
 
 741 
 
 0.76 
 
 1.32 
 
 0.670 
 
 0.783 
 
 Available Energy in Expanding Steam. Rankine Cycle. (J. B. 
 Stan wood, Power, June 9, 1908.) A simple formula for finding, with tha 
 aid of the steam and entropy tables, the available energy per pound of 
 steam in B.T.U. when it is expanded adiabatically from a higher to a 
 lower pressure is: 
 
 U = H - Hi + T (Ni - N). 
 
 U = available B.T.U. in 1 Ib. of expanding steam; H and H\ total heat 
 in 1 Ib. steam at the two pressures; T = absolute temperature at the 
 lower pressure; N N\, difference of entropy of 1 Ib. of steam at the two 
 pressures. 
 
 EXAMPLE. Required the available B.T.U. in 1 Ib. steam expanded 
 from 100 Ibs. to 14.7 Ibs. absolute. H = 1186.3; Hi = 1150.4; T = 672; 
 N = 1.602; Ni = 1.756. 35.9 + 103.5 = 138.4. 
 
 Efficiency of the Cycle. Let the steam be made from feed-water at 
 212. Heat required = 1186.3 - 180 = 1006.3; efficiency = 138.4 -*- 
 1006.3 = 0.1375. 
 
 Rankine Cycle. This efficiency is that of the Rankine cycle, which 
 assumes that the steam is expanded adiabatically to the lowest pressure 
 and temperature, and that the feed-water from which the steam is made 
 is introduced into the system at the same low temperature. 
 
 Carnot Cycle. The Carnot ideal cycle, which assumes that all. the 
 heat entering the system enters at the highest temperature, and in which 
 the efficiency is (Ti - Tt) + Ti, gives (327.8- 212) -*- (327.8+ 460) = 
 1470 and the available energy inB.T.U.=0. 1470X1006.3 = 147.9 B.T.U. 
 
228 MC ANDREW'S FLOATING SCHOOL 
 
 WIRE AND SHEET-METAL, GAUGES COMPARED. 
 
 
 Sc 
 
 . 
 
 -0 6 
 
 - -o 
 
 British Imperial 
 
 g _: 
 
 . 
 
 g 
 
 *S| 
 
 c*o Si 
 
 S^ 3 
 
 " MCO 
 
 Standard 
 
 S (-,j2 oj 
 
 o 
 
 fe> 
 
 
 G * 03 
 
 03 n 
 
 02 i a 
 
 Wire Gauge. 
 
 'c ; 2^ . 
 
 <u 8*. 
 
 II 
 
 s 2 ^ 
 
 I i^ 
 
 III 
 
 
 (Legal Standard 
 
 Islli 
 
 J9 SJ 
 
 81 
 
 |o 
 
 l| 
 
 s|l 
 
 p ^ C 
 
 " S * 
 
 a3,o3 o 
 
 ||| 
 
 in Great Britain 
 since 
 
 odff | 
 
 
 
 n sf 
 
 ^ oi 
 
 <gs 
 
 "^ 
 
 March 1, 1884.) 
 
 ^ 
 
 
 
 inch. 
 
 inch. 
 
 inch. 
 
 inch. 
 
 inch. 
 
 millim. 
 
 inch. 
 
 
 0000000 
 
 
 
 .49 
 
 
 .500 
 
 12.7 
 
 .5 
 
 7/0 
 
 000000 
 
 
 
 .46 
 
 
 .464 
 
 11.73 
 
 .469 
 
 6-0 
 
 00000 
 
 
 
 .43 
 
 
 .432 
 
 10.97 
 
 .438 
 
 5/0 
 
 0000 
 
 .454 
 
 .46 
 
 .393 
 
 
 .4 
 
 10.16 
 
 .406 
 
 4/ 
 
 000 
 
 .425 
 
 .40964 
 
 .362 
 
 
 .372 
 
 9.45 
 
 .375 
 
 3/0 
 
 00 
 
 .38 
 
 .3648 
 
 .331 
 
 
 .348 
 
 8.84 
 
 .344 
 
 2/0 
 
 
 
 .34 
 
 .32486 
 
 .307 
 
 
 .324 
 
 8.23 
 
 .313 
 
 
 
 1 
 
 .3 
 
 .2893 
 
 .283 
 
 .227 
 
 .3 
 
 7.62 
 
 .281 
 
 1 
 
 2 
 
 .284 
 
 .25763 
 
 .263 
 
 .219 
 
 .276 
 
 7.01 
 
 .266 
 
 2 
 
 3 
 
 .259 
 
 .22942 
 
 .244 
 
 .212 
 
 .252 
 
 6.4 
 
 .25 
 
 3 
 
 4 
 
 .23-3 
 
 .20431 
 
 .225 
 
 .207 
 
 .232 
 
 5.89 
 
 .234 
 
 4 
 
 5 
 
 .22 
 
 .18194 
 
 .207 
 
 .204 
 
 .212 
 
 5.38 
 
 .219 
 
 5 
 
 6 
 
 .203 
 
 .16202 
 
 .192 
 
 .201 
 
 .192 
 
 4.88 
 
 .203 
 
 6 
 
 7 
 
 .18 
 
 .14428 
 
 .177 
 
 .199 
 
 .176 
 
 4.47 
 
 .188 
 
 7 
 
 8 
 
 .165 
 
 .12849 
 
 .162 
 
 .197 
 
 .16 
 
 4.06 
 
 .172 
 
 8 
 
 9 
 
 .148 
 
 .11443 
 
 .148 
 
 .194 
 
 .144 
 
 3.66 
 
 .156 
 
 9 
 
 10 
 
 .134 
 
 .J0189 
 
 .135 
 
 .191 
 
 .128 
 
 3.25 
 
 .141 
 
 10 
 
 11 
 
 .12 
 
 .09074 
 
 .12 
 
 .188 
 
 .116 
 
 2.95 
 
 .125 
 
 11 
 
 12 
 
 .109 
 
 .08081 
 
 .105 
 
 .185 
 
 .104 
 
 2.64 
 
 .109 
 
 12 
 
 13 
 
 .095 
 
 .07196 
 
 .092 
 
 .182 
 
 .092 
 
 2.34 
 
 .094 
 
 13 
 
 14 
 
 .033 
 
 .06408 
 
 .08 
 
 .180 
 
 .08 
 
 2.03 
 
 .078 
 
 14 
 
 15 
 
 .072 
 
 .05707 
 
 .072 
 
 .178 
 
 .072 
 
 1.83 
 
 .07 
 
 15 
 
 16 
 
 .065 
 
 .05032 
 
 .063 
 
 .175 
 
 .064 
 
 1.63 
 
 .0625 
 
 16 
 
 17 
 
 .053 
 
 .04526 
 
 .054 
 
 .172 
 
 .056 
 
 1.42 
 
 .0563 
 
 17 
 
 18 
 
 .049 
 
 .0403 
 
 .047 
 
 .168 
 
 .048 
 
 1.22 
 
 .05 
 
 18 
 
 19 
 
 .042 
 
 .03589 
 
 .041 
 
 164 
 
 .04 
 
 1.02 
 
 .0438 
 
 19 
 
 20 
 
 .035 
 
 .03196 
 
 .035 
 
 .161 
 
 .036 
 
 .91 
 
 .0375 
 
 20 
 
 21 
 
 .032 
 
 .02846 
 
 .032 
 
 .157 
 
 .032 
 
 .81 
 
 .0344 
 
 21 
 
 22 
 
 028 
 
 .02535 
 
 .028 
 
 .155 
 
 .028 
 
 .71 
 
 .0313 
 
 22 
 
 23 
 
 .025 
 
 .02257 
 
 .025 
 
 .153 
 
 .024 
 
 .61 
 
 .0281 
 
 23 
 
 24 
 
 .022 
 
 .0201 
 
 .023 
 
 .151 
 
 .022 
 
 .56 
 
 .025 
 
 24 
 
 25 
 
 .02 
 
 .0179 
 
 .02 
 
 .148 
 
 .02 
 
 .51 
 
 .0219 
 
 25 
 
 26 
 
 .018 
 
 .01594 
 
 .018 
 
 .146 
 
 .018 
 
 .46 
 
 .0188 
 
 26 
 
 27 
 
 .016 
 
 .01419 
 
 .017 
 
 .143 
 
 .0164 
 
 .42 
 
 .0172 
 
 27 
 
 28 
 
 .014 
 
 .01264 
 
 .016 
 
 .139 
 
 .0148 
 
 .38 
 
 .0156 
 
 28 
 
 29 
 
 .013 
 
 .01126 
 
 .015 
 
 .134 
 
 .0136 
 
 .35 
 
 .0141 
 
 29 
 
 30 
 
 .012 
 
 .01002 
 
 .014 
 
 .127 
 
 .0124 
 
 .31 
 
 .0125 
 
 30 
 
 31 
 
 .01 
 
 .00893 
 
 .013 
 
 .120 
 
 .0116 
 
 .29 
 
 .0109 
 
 31 
 
 32 
 
 .009 
 
 .00795 
 
 .013 
 
 .115 
 
 .0108 
 
 .27 
 
 .0101 
 
 32 
 
 33 
 
 .003 
 
 .00708 
 
 .011 
 
 .112 
 
 .01 
 
 .25 
 
 .0094 
 
 33 
 
 34 
 
 .007 
 
 .0063 
 
 .01 
 
 .110 
 
 .0092 
 
 .23 
 
 .0086 
 
 34 
 
 35 
 
 .005 
 
 .00561 
 
 .00 
 
 .108 
 
 .0084 
 
 .21 
 
 .0078 
 
 35 
 
 36 
 
 .004 
 
 .005 
 
 .009 
 
 .106 
 
 .0076 
 
 .19 
 
 .007 
 
 36 
 
 37 
 
 
 .00445 
 
 .0085 
 
 .103 
 
 .0068 
 
 .17 
 
 .0066 
 
 37 
 
 38 
 
 
 .00396 
 
 .008 
 
 .101 
 
 .006 
 
 .15 
 
 .0063 
 
 38 
 
 39 
 
 
 .00353 
 
 .0075 
 
 099 
 
 .0052 
 
 .13 
 
 
 39 
 
 40 
 
 
 .00314 
 
 .007 
 
 097 
 
 .0048 
 
 .12 
 
 
 40 
 
 41 
 
 
 
 
 .095 
 
 .0044 
 
 .11 
 
 
 41 
 
 42 
 
 
 
 
 .092 
 
 .004 
 
 .10 
 
 
 42 
 
 43 
 
 
 
 
 .088 
 
 .0036 
 
 .09 
 
 
 43 
 
 44 
 
 
 
 
 .085 
 
 .0032 
 
 .08 
 
 
 44 
 
 45 
 
 
 
 
 .081 
 
 .0028 
 
 .07 
 
 
 45 
 
 46 
 
 
 
 
 .079 
 
 .0024 
 
 .06 
 
 
 46 
 
 47 
 
 
 
 
 .077 
 
 .002 
 
 .05 
 
 
 47 
 
 48 
 
 
 
 
 .075 
 
 .0016 
 
 .04 
 
 
 48 
 
 49 
 
 
 
 
 .092 
 
 .0012 
 
 .03 
 
 
 49 
 
 50 
 
 
 
 
 .069 
 
 .001 
 
 .025 
 
 
 50 
 
 Republished by permission of Messrs. John Wiley & Sons, 
 from Kent's Mechanical Engineers Pocket- Book. 
 
 Inc. 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 229 
 
 SQUARES, CUBES, SQUARE ROOTS AND CUBE ROOTS OF 
 NUMBERS FROM O.I TO 16OO. 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 0.1 
 
 .01 
 
 .001 
 
 .3162 
 
 .4642 
 
 3.1 
 
 9.61 
 
 29.791 
 
 .761 
 
 ^ 
 
 .15 
 
 .0225 
 
 .0034 
 
 .3873 
 
 .5313 
 
 .2 
 
 10.24 
 
 32.768 
 
 .789 
 
 .474 
 
 .2 
 
 .04 
 
 .008 
 
 .4472 
 
 .5846 
 
 .3 
 
 1089 
 
 35.937 
 
 .817 
 
 489 
 
 .25 
 
 .0625 
 
 .0156 
 
 .500 
 
 .6300 
 
 4 
 
 11.56 
 
 39.304 
 
 .844 
 
 504 
 
 .3 
 
 .09 
 
 .027 
 
 .5477 
 
 .6694 
 
 .5 
 
 12.2!) 
 
 42.875 
 
 .871 
 
 .518 
 
 .35 
 
 .1225 
 
 .0429 
 
 .5916 
 
 .7047 
 
 .6 
 
 12.96 
 
 46656 
 
 .897 
 
 533 
 
 .4 
 
 16 
 
 .064 
 
 .6325 
 
 .7368 
 
 .7 
 
 13.69 
 
 50.653 
 
 .924 
 
 .547 
 
 .45 
 
 .2025 
 
 .0911 
 
 .6708 
 
 .7663 
 
 .8 
 
 14.44 
 
 54.872 
 
 .949 
 
 .560 
 
 .5 
 
 .25 
 
 .125 
 
 .7071 
 
 .793} 
 
 .9 
 
 15.21 
 
 59.319 
 
 .975 
 
 574 
 
 .55 
 
 .3025 
 
 .1664 
 
 .7416 
 
 .8193 
 
 4. 
 
 16. 
 
 64. 
 
 2. 
 
 .5874 
 
 .6 
 
 .36 
 
 .216 
 
 .7746 
 
 .8434 
 
 1 
 
 16.81 
 
 68.921 
 
 2025 
 
 .601 
 
 .65 
 
 .4225 
 
 .2746 
 
 .8062 
 
 .8662 
 
 .2 
 
 17.64 
 
 74.088 
 
 2049 
 
 .613 
 
 .7 
 
 .49 
 
 .343 
 
 .8367 
 
 .88?c 
 
 .3 
 
 18.49 
 
 79.507 
 
 2.C74 
 
 .626 
 
 .75 
 
 .5625 
 
 .4219 
 
 .8660 
 
 .9086 
 
 .4 
 
 19.36 
 
 85.184 
 
 2.C98 
 
 1.639 
 
 .8 
 
 .64 
 
 .512 
 
 .8944 
 
 .9283 
 
 .5 
 
 20.25 
 
 91.125 
 
 2.121 
 
 1.651 
 
 .85 
 
 .7225 
 
 .6141 
 
 .9219 
 
 .9473 
 
 .6 
 
 21.16 
 
 97.336 
 
 2.145 
 
 1 .663 
 
 9 
 
 .81 
 
 .729 
 
 .9487 
 
 .9655 
 
 .7 
 
 22.09 
 
 103.823 
 
 2 1C8 
 
 1 b75 
 
 .95 
 
 .9025 
 
 .8574 
 
 .9747 
 
 .9830 
 
 .8 
 
 23.04 
 
 110.592 
 
 2.191 
 
 1.687 
 
 1. 
 
 1. 
 
 
 
 1. 
 
 .9 
 
 24.01 
 
 117.64? 
 
 2214 
 
 1.690 
 
 1.05 
 
 1.1025 
 
 J58 
 
 !025 
 
 1.016 
 
 5. 
 
 25. 
 
 125. 
 
 2.2361 
 
 1.7100 
 
 1.1 
 
 1.21 
 
 .331 
 
 049 
 
 1.032 
 
 .1 
 
 26.01 
 
 132.651 
 
 2258 
 
 .721 
 
 1.15 
 
 1.3225 
 
 .521 
 
 .072 
 
 1.048 
 
 .2 
 
 27.04 
 
 140.608 
 
 2.280 
 
 .732 
 
 1.2 
 
 1.44 
 
 .728 
 
 .095 
 
 1.063 
 
 .3 
 
 23.09 
 
 148.877 
 
 2.302 
 
 .744 
 
 1.25 
 
 1.5625 
 
 953 
 
 .118 
 
 1.077 
 
 .4 
 
 29.16 
 
 157.464 
 
 2324 
 
 .754 
 
 1.3 
 
 1.69 
 
 2.197 
 
 .140 
 
 1.091 
 
 .5 
 
 30.25 
 
 166.375 
 
 2.345 
 
 .765 
 
 1.35 
 
 1.8225 
 
 2.460 
 
 .162 
 
 .105 
 
 .6 
 
 31.36 
 
 175.616 
 
 2.366 
 
 .776 
 
 1.4 
 
 1.96 
 
 2.744 
 
 .183 
 
 .119 
 
 .7 
 
 32.49 
 
 185 193 
 
 2.387 
 
 .786 
 
 1.45 
 
 2.1025 
 
 3.049 
 
 .204 
 
 132 
 
 .8 
 
 33.64 
 
 195.112 
 
 2408 
 
 .797 
 
 1.5 
 
 2.25 
 
 3.375 
 
 .2247 
 
 .1447 
 
 .9 
 
 34.81 
 
 205.379 
 
 2.429 
 
 .807 
 
 1.55 
 
 2.4025 
 
 3.724 
 
 .245 
 
 .157 
 
 a. 
 
 36. 
 
 216. 
 
 2.4495 
 
 .8171 
 
 1.6 
 
 2.56 
 
 4.096 
 
 .265 
 
 .170 
 
 .1 
 
 37.21 
 
 226.981 
 
 2.470 
 
 .827 
 
 1.65 
 
 2.7225 
 
 4.492 
 
 .285 
 
 .182 
 
 .2 
 
 38.44 
 
 238.328 
 
 2.490 
 
 .837 
 
 1.7 
 
 2.89 
 
 4913 
 
 .304 
 
 .193 
 
 .3 
 
 39.69 
 
 250.047 
 
 2,510 
 
 .847 
 
 1.75 
 
 3.0625 
 
 5.359 
 
 .323 
 
 .205 
 
 .4 
 
 40.96 
 
 262.144 
 
 2530 
 
 .857 
 
 1.8 
 
 3.24 
 
 5.832 
 
 .342 
 
 .216 
 
 .5 
 
 42.25 
 
 274.625 
 
 2.550 
 
 .866 
 
 1.85 
 
 3.4225 
 
 6.332 
 
 .360 
 
 .228 
 
 .6 
 
 43.56 
 
 287.496 
 
 2.569 
 
 1.876 
 
 1.9 
 
 3.61 
 
 6.859 
 
 .378 
 
 .239 
 
 .7 
 
 44.89 
 
 300.763 
 
 2.588 
 
 1.885 
 
 1.95 
 
 3.8025 
 
 7.415 
 
 .396 
 
 .249 
 
 .8 
 
 46.24 
 
 314.432 
 
 2.603 
 
 1.895 
 
 2. 
 
 4. 
 
 8. 
 
 .4142 
 
 .2599 
 
 .9 
 
 47.61 
 
 328.509 
 
 2.627 
 
 1.904 
 
 .1 
 
 4.41 
 
 9.261 
 
 .449 
 
 .281 
 
 7. 
 
 49. 
 
 343. 
 
 2.6458 
 
 1.9129 
 
 .2 
 
 4.84 
 
 10.648 
 
 .483 
 
 .301 
 
 .1 
 
 50.41 
 
 357.911 
 
 2.665 
 
 1.922 
 
 .3 
 
 5.29 
 
 12.167 
 
 .517 
 
 .320 
 
 .2 
 
 51.84 
 
 373.248 
 
 2.683 
 
 1.931 
 
 .4 
 
 5.76 
 
 13.824 
 
 .549 
 
 .339 
 
 .3 
 
 53.29 
 
 389.017 
 
 2.702 
 
 1 940 
 
 .5 
 
 6.25 
 
 15.625 
 
 .581 
 
 .357 
 
 .4 
 
 54.76 
 
 405.224 
 
 2.720 
 
 1.949 
 
 .6 
 
 6.76 
 
 17.576 
 
 .612 
 
 .375 
 
 .5 
 
 56.25 
 
 421.875 
 
 2.739 
 
 1.957 
 
 .7 
 
 7.29 
 
 19.683 
 
 .643 
 
 .392 
 
 .6 
 
 57.76 
 
 438.976 
 
 2.757 
 
 1.966 
 
 ,8 
 
 7.84 
 
 21.952 
 
 .673 
 
 .409 
 
 .7 
 
 59.29 
 
 456.533 
 
 2.775 
 
 1.975 
 
 .9 
 
 8.41 
 
 24.389 
 
 .703 
 
 .426 
 
 .8 
 
 60.84 
 
 474.552 
 
 2.793 
 
 1.983 
 
 3. 
 
 9. 
 
 27. 
 
 .7321 
 
 .4422 
 
 .9 
 
 62.41 
 
 493.039 
 
 2.811 
 
 .992 
 
 Republished by permission of Messrs. John Wiley & Sons, Inc. 
 from Kent's Mechanical Engineers Pocket- Book. 
 
230 
 
 C ANDREW'S FLOATING SCHOOL 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No 
 
 Square 
 
 Cube. 
 
 Sq. 
 
 Root. 
 
 Cube 
 Root. 
 
 8. 
 
 64. 
 
 512. 
 
 2.8284 
 
 2. 
 
 45 
 
 2025 
 
 9112." 
 
 6.7082 3.ii69 
 
 .1 
 
 65.61 
 
 531.441 
 
 2846 
 
 2.008 
 
 46 
 
 2116 
 
 97336 
 
 6.7823 3 5830 
 
 .2 
 
 67.24 
 
 551.368 
 
 2.864 
 
 2.017 
 
 47 
 
 2209 
 
 103823 
 
 6.65571 3.6088 
 
 .3 
 
 68.89 
 
 571.787 
 
 2.881 
 
 2.025 
 
 43 
 
 2304 
 
 110592 
 
 6.9282 
 
 3.6342 
 
 A 
 
 70.56 
 
 592.704 
 
 2.898 
 
 2.033 
 
 49 
 
 2401 
 
 1 1 7649 
 
 7. 
 
 3.6593 
 
 .5 
 
 72.25 
 
 614.125 
 
 2.915 
 
 2.041 
 
 50 
 
 2500 
 
 125000 
 
 7.0711 
 
 3.6840 
 
 .6 
 
 73.96 
 
 636.056 
 
 2.933 
 
 2.049 
 
 51 
 
 2601 
 
 132651 
 
 7J.414 
 
 3.7084 
 
 .7 
 
 75.69 
 
 653.503 
 
 2.950 
 
 2.057 
 
 52 
 
 2704 
 
 140608 
 
 7.2111 
 
 3.7325 
 
 .8 
 
 77.44 
 
 681.472 
 
 2.966 
 
 2.065 
 
 53 
 
 2309 
 
 143377 
 
 7.2801 
 
 3.7563 
 
 .9 
 
 79.21 
 
 704.969 
 
 2.983 
 
 2.072 
 
 54 
 
 2916 
 
 157464 
 
 7.3485 
 
 3.7798 
 
 9. 
 
 81. 
 
 729. 
 
 3. 
 
 2.0801 
 
 55 
 
 3025 
 
 166375 
 
 7.4162 
 
 3.8030 
 
 .1 
 
 82.81 
 
 753.571 
 
 3.017 
 
 2.088 
 
 56 
 
 3136 
 
 175616 
 
 7.4833 
 
 3.8259 
 
 .2 
 
 84.64 
 
 778.688 
 
 3.033 
 
 2.095 
 
 57 
 
 3249 
 
 185193 
 
 7.5498 
 
 3.8485 
 
 .3 
 
 86.49 
 
 804.357 
 
 3.050 
 
 2.103 
 
 53 
 
 3364 
 
 195112 
 
 7.6158 
 
 3.8709 
 
 .4 
 
 83.36 
 
 830.584 
 
 3.066 
 
 2.110 
 
 59 
 
 3481 
 
 205379 
 
 7,6811 
 
 3.8930 
 
 .5 
 
 90.25 
 
 857.375 
 
 3.082 
 
 2.118 
 
 60 
 
 3600 
 
 216000 
 
 7.7460 
 
 3.9149 
 
 .6 
 
 92.16 
 
 884.736 
 
 3.098 
 
 2.125 
 
 61 
 
 3721 
 
 22698 1 
 
 7.8102 
 
 3.9365 
 
 .7 
 
 94.09 
 
 912.673 
 
 3.114 
 
 2.133 
 
 62 
 
 3344 
 
 238328 
 
 7.8740 
 
 3.9579 
 
 .8 
 
 96.04 
 
 941.192 
 
 3.130 
 
 2.140 
 
 63 
 
 3969 
 
 250047 
 
 7.9373 
 
 3.9791 
 
 .9 
 
 98.01 
 
 970.299 
 
 3.146 
 
 2.147 
 
 64 
 
 4096 
 
 262144 
 
 8. 
 
 4. 
 
 10 
 
 100 
 
 1000 
 
 3.1623 
 
 2.1544 
 
 65 
 
 4225 
 
 274625 
 
 8.0623 
 
 4.0207 
 
 11 
 
 121 
 
 1331 
 
 3.3166 
 
 2.2240 
 
 66 
 
 4356 
 
 287496 
 
 8.1240 
 
 4.0412 
 
 12 
 
 144 
 
 1728 
 
 3.4641 
 
 2.2894 
 
 67 
 
 4489 
 
 300763 
 
 8.1854 
 
 4.0615 
 
 13 
 
 169 
 
 2197 
 
 3.6056 
 
 2.3513 
 
 68 
 
 4624 
 
 3 1 4432 
 
 8.2462 
 
 4.0817 
 
 14 
 
 196 
 
 2744 
 
 3.7417 
 
 2.4101 
 
 69 
 
 4761 
 
 328509 
 
 8.3066 
 
 4.1016 
 
 15 
 
 225 
 
 3375 
 
 3.8730 
 
 2.4662 
 
 70 
 
 4900 
 
 343000 
 
 8.3666 
 
 4.1213 
 
 16 
 
 256 
 
 4096 
 
 4 
 
 2.5198 
 
 71 
 
 5041 
 
 357911 
 
 8.4261 
 
 4.1408 
 
 17 
 
 289 
 
 4913 
 
 4.1231 
 
 2.5713 
 
 72 
 
 5184 
 
 373248 
 
 8.4853 
 
 4.1602 
 
 18 
 
 324 
 
 5832 
 
 4.2426 
 
 2.6207 
 
 73 
 
 5329 
 
 389017 
 
 8.5440 
 
 4. 1 793 
 
 19 
 
 361 
 
 6859 
 
 4.3589 
 
 2.6684 
 
 74 
 
 5476 
 
 405224 
 
 8.6023 
 
 4.1983 
 
 20 
 
 400 
 
 8000 
 
 4.4721 
 
 2.7144 
 
 75 
 
 5625 
 
 421875 
 
 8.6603 
 
 4.2172 
 
 21 
 
 441 
 
 9261 
 
 4.5826 
 
 2.7589 
 
 76 
 
 5776 
 
 438976 
 
 8.7178 
 
 4.2358 
 
 22 
 
 484 
 
 10648 
 
 4.6904 
 
 2.8020 
 
 77 
 
 5929 
 
 456533 
 
 8.7750 
 
 4.2543 
 
 23 
 
 529 
 
 12167 
 
 4.7958 
 
 28439 
 
 78 
 
 6084 
 
 474552 
 
 8.8318 
 
 4.2727 
 
 24 
 
 576 
 
 13824 
 
 4.8990 
 
 2.8845 
 
 79 
 
 6241 
 
 493039 
 
 8.8882 
 
 4.2908 
 
 25 
 
 625 
 
 15625 
 
 5. 
 
 2.9240 
 
 80 
 
 6400 
 
 512000 
 
 8.9443 
 
 4.3089 
 
 26 
 
 676 
 
 17576 
 
 5.0990 
 
 2.9625 
 
 81 
 
 6561 
 
 531441 
 
 9 
 
 4.3267 
 
 27 
 
 729 
 
 19683 
 
 5.1962 
 
 3. 
 
 82 
 
 6724 
 
 551368 
 
 9.0554 
 
 4.3445 
 
 28 
 
 784 
 
 21952 
 
 5.2915 
 
 3.0366 
 
 83 
 
 6839 
 
 571787 
 
 9.1104 
 
 43621 
 
 29 
 
 841 
 
 24389 
 
 5.3852 
 
 3.0723 
 
 84 
 
 7056 
 
 592704 
 
 9.1652 
 
 4.3795 
 
 30 
 
 900 
 
 27000 
 
 5.4772 
 
 3.1072 
 
 85 
 
 7225 
 
 614125 
 
 9.2195 
 
 4.3968 
 
 31 
 
 961 
 
 29791 
 
 5.5678 
 
 3.1414 
 
 86 
 
 7396 
 
 636056 
 
 9.2736 
 
 4.4140 
 
 32 
 
 1024 
 
 32768 
 
 5.6569 
 
 3.1748 
 
 87 
 
 7569 
 
 658503 
 
 9.3276 
 
 4.4310 
 
 33 
 
 1039 
 
 35937 
 
 5.7446 
 
 3.2075 
 
 88 
 
 7744 
 
 631472 
 
 9.3808 
 
 4.446v> 
 
 34 
 
 1156 
 
 39304 
 
 5.8310 
 
 3.2396 
 
 89 
 
 7921 
 
 704969 
 
 9.4340 
 
 4.4647 
 
 35 
 
 1225 
 
 42875 
 
 5.9161 
 
 3.2711 
 
 90 
 
 8100 
 
 729000 
 
 94868 
 
 4.4814 
 
 36 
 
 1296 
 
 46656 
 
 6. 
 
 3.3019 
 
 91 
 
 8281 
 
 753571 
 
 9.5394 
 
 4.4979 
 
 37 
 
 1369 
 
 50653 
 
 6.0828 
 
 3.332; 
 
 92 
 
 8464 
 
 778688 
 
 9.5917 
 
 4.5144 
 
 38 
 
 1444 
 
 54872 
 
 6.1644 
 
 3.3620 
 
 93 
 
 8649 
 
 804357 
 
 96437 
 
 4.5307 
 
 39 
 
 1521 
 
 59319 
 
 6.2450 
 
 3.3912 
 
 94 
 
 8836 
 
 830584 
 
 9.6954 
 
 4.5468 
 
 40 
 
 1600 
 
 64000 
 
 6.3246 
 
 3.4200 
 
 95 
 
 9025 
 
 857375 
 
 9.7468 
 
 4.5629 
 
 41 
 
 1681 
 
 68921 
 
 64031 
 
 3.4482 
 
 96 
 
 9216 
 
 884736 
 
 9.7980 
 
 4.5789 
 
 42 
 
 1764 
 
 74083 
 
 6.4807 
 
 3.4760 
 
 97 
 
 9409 
 
 912673 
 
 98^89 
 
 4.5947 
 
 43 
 
 1849 
 
 79507 
 
 6.5574 
 
 3.5034 
 
 98 
 
 9604 
 
 941 192 
 
 9.8995 
 
 4.6104 
 
 44 
 
 1936 
 
 85184 
 
 6.6332 
 
 3.5303 
 
 99 
 
 9801 
 
 970299 
 
 9 9499 
 
 4.6261 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 231 
 
 No. 
 
 Sq. 
 
 Cube 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 1JJ 
 
 lUJUJ 
 
 1 00000 J 
 
 10. 
 
 4.6416 
 
 155 24C25 
 
 3723875 
 
 12.4499 
 
 5.3717 
 
 131 
 
 10231 
 
 1030301 
 
 10.0499 
 
 4.6570 
 
 156 24336 
 
 3796416 
 
 12.4900 
 
 5.3832 
 
 132 
 
 10434 
 
 1061203 
 
 10.0995 
 
 4.6723 
 
 157 
 
 24649 
 
 3869893 
 
 12.5300 
 
 5 3947 
 
 103 
 
 10609 
 
 1092727 
 
 10.1489 
 
 4.6875 
 
 158 
 
 24964 
 
 3944312 
 
 12.5698 
 
 5 4061 
 
 104 
 
 10316 
 
 1124864 
 
 10.1980 
 
 4.7027 
 
 159 
 
 25281 
 
 4019679 
 
 12.6095 
 
 5.4175 
 
 105 
 
 11025 
 
 1157625 
 
 10.2470 
 
 4.7177 
 
 160 
 
 25600 
 
 4096000 
 
 12.6491 
 
 5.4288 
 
 135 
 
 11236 
 
 1191016 
 
 10.2956 
 
 4.7326 
 
 161 
 
 25921 
 
 4173281 
 
 12.6886 
 
 5.4401 
 
 137 
 
 1 1449 
 
 1225043 
 
 10.3441 
 
 4.7475 
 
 162 
 
 26244 
 
 425 1 528 
 
 12.7279 
 
 5.4514 
 
 133 
 
 11664 
 
 1259712 
 
 10.3923 
 
 4.7622 
 
 163 
 
 26569 
 
 4330747 
 
 12.7671 
 
 5.4626 
 
 139 
 
 11831 
 
 1295029 
 
 10.4403 
 
 4.7769 
 
 164 
 
 26896 
 
 4410944 
 
 12.8062 
 
 5.4737 
 
 110 
 
 12100 
 
 1331000 
 
 10.4881 
 
 4.7914 
 
 165 
 
 27225 
 
 4492 1 25 
 
 12.8452 
 
 5.4848 
 
 111 
 
 12321 
 
 1367631 
 
 10.5357 
 
 4.8059 
 
 166 
 
 27556 
 
 4574296 
 
 12.8841 
 
 5.4959 
 
 112 
 
 12544 
 
 1404923 
 
 10.5830 
 
 4.8203 
 
 167 
 
 27889 
 
 4657463 
 
 12.9228 
 
 5.5069 
 
 113 
 
 12769 
 
 1442397 
 
 10.6301 
 
 4.8346 
 
 168 
 
 28224 
 
 4741632 
 
 12.9615 
 
 5.5178 
 
 114 
 
 12996 
 
 1431544 
 
 10.6771 
 
 4.8488 
 
 169 
 
 28561 
 
 4826809 
 
 13.0000 
 
 5.5288 
 
 115 
 
 13225 
 
 1520375 
 
 10.7238 
 
 4.8629 
 
 170 
 
 28900 
 
 4913000 
 
 13.0384 
 
 5.5397 
 
 115 
 
 13436 
 
 1560396 
 
 10.7703 
 
 4.8770 
 
 171 
 
 29241 
 
 50002 1 1 
 
 13.0767 
 
 5.5505 
 
 117 
 
 13639 
 
 1601613 
 
 10.8167 
 
 4.8910 
 
 172 
 
 29584 
 
 5088448 
 
 13.1149 
 
 5.5613 
 
 113 
 
 13924 
 
 1643032 
 
 10.8628 
 
 4.9049 
 
 173 
 
 29929 
 
 5177717 
 
 13.1529 
 
 5.5721 
 
 119 
 
 14151 
 
 1635159 
 
 10.9087 
 
 4.9187 
 
 .174 
 
 30276 
 
 5268024 
 
 13.1909 
 
 5.5828 
 
 120 
 
 14403 
 
 1 728000 
 
 10.9545 
 
 4.9324 
 
 175 
 
 30625 
 
 5359375 
 
 13.2288 
 
 5.5934 
 
 121 
 
 14641 
 
 1771561 
 
 1 1 .0000 
 
 4.946 
 
 176 
 
 30976 
 
 5451776 
 
 13.2665 
 
 5.6041 
 
 122 
 
 14334 
 
 1815343 
 
 11.0454 
 
 49597 
 
 177 
 
 31329 
 
 5545233 
 
 13.3041 
 
 5.6147 
 
 123 
 
 15129 
 
 1860367 
 
 1 1 .0905 
 
 4.9732 
 
 178 
 
 31684 
 
 5639752 
 
 13.3417 
 
 5.6252 
 
 124 
 
 15376 
 
 1906624 
 
 11.1355 
 
 4.9866 
 
 179 
 
 32041 
 
 5735339 
 
 13.3791 
 
 5.6357 
 
 125 
 
 15625 
 
 1953125 
 
 11.1803 
 
 5.0000 
 
 180 
 
 32400 
 
 5832000 
 
 13.4164 
 
 5.6462 
 
 125 
 
 15376 
 
 2000376 
 
 11.2250 
 
 5.0133 
 
 181 
 
 32761 
 
 5929741 
 
 13.4536 
 
 5.6567 
 
 127 
 
 16129 
 
 2043333 
 
 1 1 .2694 
 
 5.0265 
 
 182 
 
 33124 
 
 6028568 
 
 13.4907 
 
 5.6671 
 
 123 
 
 16334 
 
 2097 1 52 
 
 11.3137 
 
 5.0397 
 
 183 
 
 33489 
 
 6128487 
 
 13.5277 
 
 5.6774 
 
 129 
 
 16641 
 
 2146639 
 
 11.3578 
 
 5.0528 
 
 184 
 
 33856 
 
 6229504 
 
 13.5647 
 
 5.6877 
 
 130 
 
 16930 
 
 2197000 
 
 11.4018 
 
 5.0658 
 
 185 
 
 34225 
 
 6331625 
 
 13.6015 
 
 5.6980 
 
 131 
 
 17161 
 
 224309! 
 
 11.4455 
 
 50788 
 
 186 
 
 34596 
 
 6434856 
 
 13.6382 
 
 5 7083 
 
 132 
 
 17424 
 
 2299963 
 
 11.4891 
 
 5.0916 
 
 187 
 
 34969 
 
 6539203 
 
 13.6748 
 
 5.7185 
 
 133 
 
 17639 
 
 2352637 
 
 11.5326 
 
 5.1045 
 
 188 
 
 35344 
 
 6644672 
 
 13.711315.7287 
 
 134 
 
 17956 
 
 2406104 
 
 11.5758 
 
 5.1172 
 
 189 
 
 35721 
 
 6751269 
 
 13.7477 
 
 5.7388 
 
 135 
 
 18225 
 
 2460375 
 
 11.6190 
 
 5.1299 
 
 190 
 
 36100 
 
 6859000 
 
 13.7840 
 
 5.7489 
 
 136 
 
 18496 
 
 2515456 
 
 11 6619 
 
 5.1426 
 
 191 
 
 36481 
 
 696787 1 
 
 13.8203 
 
 5.7590 
 
 137 
 
 18769 
 
 2571353 
 
 11.7047 
 
 5.155 
 
 192 
 
 36864 
 
 7077888 
 
 13.8564 
 
 5.7690 
 
 133 
 
 19044 
 
 2623072 
 
 11.7473 
 
 5.1676 
 
 193 
 
 37249 
 
 7189057 
 
 13.8924 
 
 5.7790 
 
 139 
 
 19321 
 
 2685619 
 
 11.7898 
 
 5.1801 
 
 194 
 
 37636 
 
 7301384 
 
 13.9284 
 
 5.7890 
 
 140 
 141 
 H2 
 
 19600 
 19331 
 20164 
 
 2744003 
 2803221 
 2363233 
 
 1 1 .8322 
 11.8743 
 1 1 9164 
 
 5.1925 
 5.2048 
 5.2171 
 
 195 
 196 
 197 
 
 38025 
 38416 
 38809 
 
 7414875 
 7529536 
 7645373 
 
 13.9642 5.7989 
 14.00005.8088 
 14.0357l5.8186 
 
 1 H 
 
 20449 
 
 2924207 
 
 11.9583 
 
 5.2293 
 
 198 
 
 39204 
 
 7762392 
 
 14.0712 
 
 5.8285 
 
 144 
 
 20735 
 
 2985934 
 
 12.0000 
 
 5.2415 
 
 199 
 
 39601 
 
 7880599 
 
 14.1067 
 
 5.8383 
 
 145 
 
 21025 
 
 3043625 
 
 120416 
 
 5 2536 
 
 200 
 
 40000 
 
 80000CO 
 
 14.1421 
 
 5.8480 
 
 146 
 
 21316 
 
 3112136 
 
 12'.0830 
 
 5.2656 
 
 201 
 
 40401 
 
 8120601 
 
 14.1774 
 
 5.8578 
 
 147 
 143 
 149 
 
 21609 
 21904 
 22201 
 
 3176523 
 3241792 
 3307949 
 
 12.1244 
 12.1655 
 12.2066 
 
 5.2776 
 5.2896 
 5.3015 
 
 202 
 203 
 204 
 
 40804 
 41209 
 41616 
 
 8242408 
 8365427 
 8489664 
 
 14.2127 
 14.2478 
 14.2829 
 
 5.8675 
 5.8771 
 5.8868 
 
 150 
 151 
 152 
 153 
 154 
 
 22500 
 22891 
 23104 
 23409 
 23716 
 
 3375000 
 3442951 
 3511803 
 3581577 
 3652264 
 
 12.2474 
 12.2882 
 12.3288 
 12.3693 
 12.4097 
 
 5.3133 
 5.325 
 5.336P 
 5.3485 
 5.360 
 
 205 
 206 
 207 
 208 
 209 
 
 42025 
 42436 
 42849 
 43264 
 43681 
 
 8615125 
 8741816 
 8869743 
 8998912 
 9129329 
 
 14.3178 
 14.3527 
 14.3875 
 14.4222 
 14.4568 
 
 5.8964 
 5.9059 
 5.9155 
 5.9250 
 5.9345 
 
232 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 No. 
 
 Sq. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 210 
 
 44100 
 
 9261000 
 
 14.4914 
 
 5.9439 
 
 ^65 
 
 70225 
 
 18609625 
 
 16.2788 
 
 6.4232 
 
 211 
 
 44521 
 
 939393 1 
 
 14.5258 
 
 5.9533 
 
 266 
 
 70756 
 
 18821096 
 
 16.3095 
 
 6.4312 
 
 212 
 
 44944 
 
 9528128 
 
 14.5602 
 
 5.9627 
 
 267 
 
 71289 
 
 19034163 
 
 16.3401 
 
 6.4393 
 
 213 
 
 45369 
 
 9663597 
 
 14.5945 
 
 5.9721 
 
 268 
 
 71824 
 
 19248832 
 
 16.3707 
 
 6.4473 
 
 214 
 
 45796 
 
 9800344 
 
 14.6287 
 
 5.9814 
 
 269 
 
 72361 
 
 19465109 
 
 16.4012 
 
 6.4553 
 
 215 
 
 46225 
 
 9938375 
 
 14.6629 
 
 5.9907 
 
 270 
 
 72900 
 
 19683000 
 
 16.4317 
 
 6.4633 
 
 216 
 
 46656 
 
 10077696 
 
 14.6969 
 
 6.0000 
 
 271 
 
 73441 
 
 19902511 
 
 1 6.462 1 
 
 6.4713 
 
 217 
 
 47089 
 
 10218313 
 
 14.7309 
 
 6.0092 
 
 272 
 
 73934 
 
 20123648 
 
 1 6.4924 
 
 6.4792 
 
 218 
 
 47524 
 
 10360232 
 
 147643 
 
 6.0185 
 
 273 
 
 74529 
 
 20346417 
 
 16.5227 
 
 6.4872 
 
 219 
 
 47961 
 
 10503459 
 
 14.7986 
 
 6.0277 
 
 274 
 
 75076 
 
 20570824 
 
 16.5529 
 
 6.4951 
 
 220 
 
 48400 
 
 10648000 
 
 14.8324 
 
 6.0368 
 
 275 
 
 75625 
 
 20796875 
 
 16.5831 
 
 6.5030 
 
 221 
 
 43341 
 
 10793861 
 
 14.8661 
 
 6.0459 
 
 276 
 
 76176 
 
 21024576 
 
 16.6132 
 
 6.5108 
 
 222 
 
 49234 
 
 10941048 
 
 14.8997 
 
 60550 
 
 277 
 
 76729 
 
 21253933 
 
 16.6433 
 
 65187 
 
 223 
 
 49729 
 
 11039567 
 
 14.9332 
 
 6.0641 
 
 278 
 
 77234 
 
 21434952 
 
 16.6733 
 
 6.5265 
 
 224 
 
 50176 
 
 11239424 
 
 14.9666 
 
 6.0732 
 
 279 
 
 77841 
 
 21717639 
 
 16.7033 
 
 6.5343 
 
 225 
 
 50625 
 
 11390625 
 
 15.0000 
 
 6.0822 
 
 280 
 
 78400 
 
 21952000 
 
 16.7332 
 
 6.5421 
 
 226 
 
 51076 
 
 1154317C 
 
 15.0333 
 
 6.0912 
 
 231 
 
 78961 
 
 22188041 
 
 16.7631 
 
 6.5499 
 
 227 
 
 51529 
 
 11697083 
 
 15.0665 
 
 6.1002 
 
 282 
 
 79524 
 
 22425768 
 
 16.7929 
 
 6.5577 
 
 223 
 
 51934 
 
 11852352 
 
 15.0997 
 
 6.1091 
 
 283 
 
 80089 
 
 22665187 
 
 16.8226 
 
 6.5654 
 
 229 
 
 52441 
 
 12008939 
 
 15.1327 
 
 6.1180 
 
 284 
 
 80656 
 
 22906304 
 
 16.8523 
 
 6.5731 
 
 230 
 
 52900 
 
 12167000 
 
 15.1658 
 
 6.1269 
 
 285 
 
 81225 
 
 23149125 
 
 16.8819 
 
 6.5808 
 
 231 
 
 53361 
 
 1232639! 
 
 15.1937 
 
 6.1358 
 
 286 
 
 81796 
 
 23393656 
 
 16.9115 
 
 6.5885 
 
 232 
 
 53824 
 
 1243716C 
 
 15.2315 
 
 6.1446 
 
 287 
 
 82369 
 
 23639903 
 
 16.9411 
 
 6.5962 
 
 233 
 
 54289 
 
 12649337 
 
 15.2643 
 
 6.1534 
 
 233 
 
 82944 
 
 23887872 
 
 16.9706 
 
 6.6039 
 
 234 
 
 54756 
 
 12812904 
 
 15.2971 
 
 6.1622 
 
 239 
 
 83521 
 
 24137569 
 
 17.0000 
 
 6.6115 
 
 235 
 
 55225 
 
 12977875 
 
 15.3297 
 
 5.1710 
 
 290 
 
 84100 
 
 24389000 
 
 17.0294 
 
 66191 
 
 236 
 
 55696 
 
 1314425C 
 
 15.3623 
 
 6.1797 
 
 291 
 
 84681 
 
 24642171 
 
 17.0587 
 
 6.6267 
 
 237 
 
 56169 
 
 13312053 
 
 15.3948 
 
 6 1885 
 
 292 
 
 85264 
 
 24897088 
 
 17.0880 
 
 6.6343 
 
 238 
 
 56644 
 
 13431272 
 
 15.4272 
 
 6.1972 
 
 293 
 
 85849 
 
 25153757 
 
 17.1172 
 
 6.6419 
 
 239 
 
 57121 
 
 13651919 
 
 15.4596 
 
 6.2058 
 
 294 
 
 86436 
 
 25412184 
 
 17.1464 
 
 6.6494 
 
 240 
 
 57600 
 
 13824000 
 
 15.4919 
 
 6.2145 
 
 295 
 
 87025 
 
 25672375 
 
 17.1756 
 
 6.6569 
 
 241 
 
 53081 
 
 13997521 
 
 15.5242 
 
 6.2231 
 
 296 
 
 87616 
 
 25934336 
 
 17.2047 
 
 6.6644 
 
 242 
 
 53564 
 
 14172483 
 
 15.5563 
 
 6.2317 
 
 297 
 
 83209 
 
 26198073 
 
 17.2337 
 
 6.6719 
 
 243 
 
 59049 
 
 14348907 
 
 15.5885 
 
 6.2403 
 
 293 
 
 88304 
 
 26463592 
 
 17.2627 
 
 6.6794 
 
 244 
 
 59536 
 
 14526784 
 
 15.6205 
 
 6.2488 
 
 299 
 
 89401 
 
 26730899 
 
 17.29 1C 
 
 6.6869 
 
 245 
 
 60025 
 
 14706125 
 
 15.6525 
 
 6.2573 
 
 300 
 
 90000 
 
 27000000 
 
 17.3205 
 
 6.6943 
 
 246 
 
 60516 
 
 14886936 
 
 15.6844 
 
 62658 
 
 301 
 
 90601 
 
 27270901 
 
 17.3494 
 
 6.7018 
 
 247 
 
 61009 
 
 1 5069223 
 
 15.7162 
 
 6.2743 
 
 302 
 
 91204 
 
 27543608 
 
 17.3781 
 
 6.7092 
 
 248 
 
 61504 
 
 15252992 
 
 15.7480 
 
 6.2828 
 
 303 
 
 91809 
 
 27818127 
 
 1 7.4069 
 
 6.7166 
 
 249 
 
 62001 
 
 1 5438249 
 
 15.7797 
 
 6.2912 
 
 304 
 
 92416 
 
 28094464 
 
 17.4356 
 
 6.7240 
 
 250 
 
 62500 
 
 15625000 
 
 15.8114 
 
 6.2996 
 
 305 
 
 93025 
 
 28372625 
 
 1 7.4642 
 
 6.7313 
 
 251 
 
 63001 
 
 15813251 
 
 15.8430 
 
 6.3030 
 
 306 
 
 93636 
 
 23652616 17.4929 
 
 6.7387 
 
 252 
 
 63504 
 
 16003003 
 
 15.8745 
 
 6.3164 
 
 307 
 
 94249 
 
 28934443117.5214 
 
 6.7460 
 
 253 
 
 64009 
 
 16194277 
 
 15.9060 
 
 6.3247 
 
 308 
 
 94864 
 
 292 181 12J 17. 5499 
 
 6.7533 
 
 254 
 
 64516 
 
 16387064 
 
 15.9374 
 
 6.3330 
 
 309 
 
 95481 
 
 29503629 
 
 17.5784 
 
 6.7606 
 
 255 
 
 65025 
 
 16581375 
 
 15.9687 
 
 6.3413 
 
 310 
 
 96100 
 
 29791000 
 
 17.6068 
 
 6.7679 
 
 256 
 
 65536 
 
 16777216 
 
 16.0000 
 
 6.3496 
 
 311 
 
 96721 
 
 300S023 1 
 
 17.6352 
 
 6.7752 
 
 257 
 
 66049 
 
 16974593 
 
 16.0312 
 
 6,3579 
 
 312 
 
 97344 
 
 30371328 
 
 17.6635 
 
 6.7824 
 
 253 
 
 66564 
 
 17173512 
 
 16.0624 
 
 6.3661 
 
 313 
 
 97969 
 
 30664297 
 
 17.6918 
 
 6.7897 
 
 259 
 
 67081 
 
 17373979 
 
 16.0935 
 
 6.3743 
 
 314 
 
 98596 
 
 30959144 
 
 17.7200 
 
 6.7969 
 
 260 
 
 67600 
 
 17576000 
 
 16.1245 
 
 6.3825 
 
 315 
 
 99225 
 
 31255875 
 
 17.7482 
 
 6.8041 
 
 261 
 
 68121 
 
 17779581 
 
 16 1555 
 
 6.3907 
 
 316 
 
 99856 
 
 31554496 
 
 17.7764 
 
 68113 
 
 262 
 
 68644 
 
 1 7984728 
 
 16 1864 
 
 63988 
 
 317 
 
 100489 
 
 31855013 
 
 17.8045 
 
 6.8185 
 
 263 
 
 69169 
 
 18191447 
 
 16.2173 
 
 6.4070 
 
 318 
 
 101124 
 
 32157432117.8326 
 
 6.8256 
 
 264 
 
 69696 
 
 18399744 
 
 16.2481 
 
 6.415 
 
 319 
 
 101761 3246175917.8606 
 
 6.8328 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 233 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Rcot. 
 
 320 
 321 
 
 102400 
 103041 
 
 32768000 
 33076161 
 
 1 7.8885 J6.8399 
 17.91656.8470 
 
 ^375 
 376 
 
 140625 
 141376 
 
 52734375 
 53157376 
 
 19.3649 
 19.3907 
 
 7.2112 
 7.2177 
 
 322 
 
 103684 
 
 33386248 
 
 17.94446.8541 
 
 377|I42129 
 
 53582633 
 
 19.4165 
 
 7^2240 
 
 323 
 
 104329 
 
 33698267 
 
 17.9722 
 
 6.8612 
 
 378 
 
 142884 
 
 54010152 
 
 19.4422 
 
 7 2304 
 
 324 
 
 104976 
 
 34012224 
 
 18.00006.8683 
 
 379 
 
 143641 
 
 54439939 
 
 19.4679 
 
 7J368 
 
 325 
 
 105625 
 
 34328125 
 
 18.02786.8753 
 
 380 
 
 1 44400 
 
 54872000 
 
 1 9.4936 
 
 72432 
 
 326 
 
 106276 
 
 34645976 
 
 18.0555 
 
 6.8824 
 
 381 
 
 145161 
 
 55306341 
 
 19.5192 
 
 7 2495 
 
 327 
 
 1 06929 
 
 34965783 
 
 18.0831 
 
 6.8894 
 
 382 
 
 145924 
 
 55742968 
 
 19 5448 
 
 7.2558 
 
 328 
 
 107584 
 
 35287552 
 
 1 8. 1 1 08 6.8964 
 
 383 
 
 1 46689 
 
 56181887 
 
 19.5704 
 
 7 2622 
 
 329 
 
 108241 
 
 35611289 
 
 18.1384 
 
 6.9034 
 
 384 
 
 147456 
 
 56623104 
 
 19.5959 
 
 7.2685 
 
 330 
 
 108900 
 
 35937000 
 
 18.1659 
 
 6.9104 
 
 385 
 
 148225 
 
 57066625 
 
 19.6214 
 
 72748 
 
 331 
 
 109561 
 
 36264691 
 
 18.1934i6.9174 
 
 386 
 
 148996 
 
 57512456 
 
 19.6469 
 
 7.2811 
 
 332 
 
 110224 
 
 36594368 
 
 18.2209 
 
 6.9244 
 
 387 
 
 1 49769 
 
 57 C 60603 
 
 19 6723 
 
 7 2874 
 
 333 
 
 110889 
 
 36926037J 18.2483 6.9313 
 
 383 
 
 1 50544 
 
 58411072 
 
 19.6977 
 
 7.2936 
 
 334 
 
 111555 
 
 37259704 
 
 18.2757 
 
 6.9382 
 
 389 
 
 151321 
 
 58863869 
 
 19.7231 
 
 7.2999 
 
 335 
 
 336 
 
 112225 
 112896 
 
 37595375 
 37933056 
 
 18.3030 
 18.3303 
 
 6.9451 
 6.9521 
 
 390 
 391 
 
 152100 
 152881 
 
 593 1 9000 
 59776471 
 
 1 9.7484 
 19.7737 
 
 7.3061 
 7.3124 
 
 337 
 
 113569 
 
 38272753 
 
 18.3576 
 
 6.9589 
 
 392 
 
 153664 
 
 60236288 
 
 19.7990 
 
 7.3166 
 
 338 
 
 114244 
 
 38614472 
 
 18.3848 
 
 6.9658 
 
 393 
 
 1 54449 
 
 60598457 
 
 19.8242 
 
 73248 
 
 339 
 
 114921 
 
 38958219 
 
 18.4120 
 
 6.9727 
 
 394 
 
 155236 
 
 61162984 
 
 19.8494 
 
 7.3310 
 
 340 
 
 1 1 5600 
 
 39304000 
 
 18.4391 
 
 6.9795 
 
 395 
 
 156025 61629875 
 
 19.8746 
 
 7.3372 
 
 341 
 
 116281 
 
 39651821 
 
 1 8.4662 
 
 6.9864 
 
 5% 
 
 156816 62099136 
 
 19.8997 
 
 7.3434 
 
 342 
 
 116964 
 
 4000 168S 
 
 18.4932 
 
 6.9932 
 
 397 
 
 157(09 
 
 62570773 
 
 19.9249 
 
 7.3496 
 
 343 
 
 1 1 7649 
 
 40353607 
 
 18.5203 
 
 7.0000 
 
 398 
 
 158404 
 
 63044792 
 
 19.9499 
 
 7.35*8 
 
 344 
 
 118336 
 
 40707584 
 
 18.5472 
 
 7.0068 
 
 399 
 
 159201 
 
 63521199 
 
 19.9750 
 
 7.3619 
 
 345 
 
 119025 
 
 41063625 
 
 18.5742 
 
 7.0136 
 
 400 
 
 160000 
 
 64000000 
 
 20.CCOO 
 
 7.3681 
 
 346 
 
 119716 
 
 41421736 
 
 18.6011 
 
 7.0203 
 
 401 
 
 leoeoi 
 
 64481201 20.0250 
 
 7 3742 
 
 347 
 
 120409 
 
 41781923 
 
 18.62797.0271 
 
 402 
 
 161(04 
 
 64964808120.0499 
 
 7.3803 
 
 348 
 
 121104 
 
 42144192 
 
 18.6548 
 
 7.0338 
 
 403 
 
 162 -'09 
 
 65450627 
 
 20.0749 
 
 7.3864 
 
 349 121801 
 
 42508549 
 
 18.6815 
 
 7.0406 
 
 404 
 
 163216 
 
 65939264 
 
 20.0998 
 
 7.3925 
 
 350 122500 
 
 42875000 
 
 18.7083 
 
 7.0473 
 
 405 
 
 164025 
 
 66430125 
 
 20.1246 
 
 7.3986 
 
 351 123201 
 
 43243551 
 
 18.7350 
 
 7.0540 
 
 406 
 
 164836 
 
 6923416 
 
 20.1494 
 
 7.4047 
 
 352 123904 
 
 436 1 4208 
 
 18.7617 
 
 7.0607 
 
 407 
 
 165649 
 
 6741914320.1742 
 
 7.4108 
 
 353 124609 
 
 43986977 
 
 18.7883 
 
 7.0674 
 
 403 
 
 166464 
 
 67917312120.1990 
 
 7.4169 
 
 354 125316 
 
 44361864 
 
 18.8149 
 
 7.0740 
 
 409 
 
 167281 
 
 68417929 
 
 20.2237 
 
 7.4229 
 
 355| 126025 
 
 44738875 
 
 18.8414 
 
 7.0807 
 
 410 
 
 168100 
 
 68921 COO 
 
 20 2485 
 
 74290 
 
 356 126736 
 
 45118016 
 
 18.8680 
 
 7.0873 
 
 411 
 
 168921 
 
 69426531 
 
 20.2731 
 
 7.4350 
 
 357, 127449 
 
 45499293 
 
 1 8 8944 
 
 70940 
 
 412 
 
 169744 
 
 69934528 
 
 20.2978 
 
 7.4410 
 
 358 128164 
 359 128881 
 
 45882712 
 46263279 
 
 1892097 1006 
 18.9473 7! 1072 
 
 413 
 414 
 
 1 70569 
 171396 
 
 70444997 
 70957944 
 
 20.3224 
 20.3470 
 
 7.4470 
 7.4530 
 
 360 
 
 129600 
 
 46656000 
 
 189737 
 
 7.1138 
 
 415 
 
 172225 
 
 7147337520.3715 
 
 7.4590 
 
 361 130321 
 
 47045881 
 
 19.0000 
 
 7.1204 
 
 4!6 
 
 173056 
 
 7199129620.3961 
 
 7.4650 
 
 362 131044 
 
 47437928 
 
 19.0263 
 
 7.1269 
 
 417 
 
 1738S9 
 
 7251171320.4206 
 
 7.4710 
 
 363 131769 
 
 47832147 
 
 19.0526 
 
 7 1335 
 
 418 
 
 174724 
 
 73034632 20.4450 
 
 7.4770 
 
 364 
 
 132496 
 
 48228544 
 
 19.0788 
 
 7.1400 
 
 419 
 
 175561 
 
 73560059 
 
 20.4695 
 
 7.4829 
 
 365 133225 
 
 48627125 
 
 19 1050 
 
 7.1466 
 
 420 
 
 1 76400 
 
 74088000 
 
 20.4939 
 
 7.4889 
 
 366 133956 
 
 49027896 
 
 19.1311 
 
 7.1531 
 
 421 
 
 177241 
 
 74618461 
 
 20.5183 
 
 7.4948 
 
 367 134689 
 
 49430863 
 
 19.1572 
 
 7.1596 
 
 422 
 
 1 78084 
 
 75151448 
 
 20.5426 
 
 7.5C07 
 
 368 135424 
 
 49836032 
 
 19.1833 
 
 7.1661 
 
 423 
 
 1 78929 
 
 75686967 20.5670 
 
 7.5067 
 
 369 
 
 136161 
 
 50243409 
 
 19.2094 
 
 7.1726 
 
 424 
 
 1 79776 
 
 76225024 
 
 20.5913 
 
 7.5126 
 
 370 
 
 1 36900 
 
 50653000 
 
 192354 
 
 7.1791 
 
 425 
 
 180625 
 
 76765625 
 
 20.6155 
 
 7.5185 
 
 371 137641 51064811 
 
 192614 
 
 7.1855 
 
 426 
 
 18'476 
 
 7730877620.6398 
 
 7.5244 
 
 372 
 
 138384 51478848 
 
 19.2873 
 
 7.1920 
 
 427 
 
 182329 
 
 77854483 20.6640 
 
 7.5302 
 
 373 
 
 139129 51895117 
 
 19.3132 
 
 7.1984 
 
 428 
 
 183184 7840275220.6882 
 
 7.5361 
 
 374 139876 52313624 
 
 19.3391 
 
 7.2048 
 
 429 
 
 184041 7895358920.7123 7.5420 
 
234 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 No. 
 430 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 184900 
 
 79507000 
 
 20.7364 7.5478 
 
 485 
 
 235225 
 
 114084125 
 
 22.0227 
 
 7.8563 
 
 431 
 
 185761 
 
 80062991 
 
 20.76057.5537 
 
 486 
 
 236196 
 
 114791256 
 
 22.0454 
 
 7 8622 
 
 432 
 
 186624 
 
 80621568 
 
 20.7846'7.5595 
 
 487 
 
 237169 
 
 115501303 
 
 220681 
 
 7 8676 
 
 433 
 
 187489 
 
 81182737 
 
 20.8087 
 
 7.5654 
 
 488 
 
 238144 
 
 116214272122.0907 
 
 7.8730 
 
 434 
 
 188356 
 
 81746504 
 
 20.8327 
 
 7.5712 
 
 489 
 
 239121 
 
 116930169 
 
 22.1133 
 
 7.8784 
 
 435 
 
 139225 
 
 82312875 
 
 20.8567 
 
 7.5770 
 
 490 
 
 240100 
 
 1 1 7649000 
 
 22.1359 
 
 7.8837 
 
 436 
 
 1 90096 
 
 82831856 
 
 20 8806 
 
 7.5828 
 
 491 
 
 241081 
 
 118370771 
 
 22.1585 
 
 7.8891 
 
 437 
 
 190969 
 
 83453453 
 
 20.9045 
 
 7.5886 
 
 492 
 
 242064 
 
 119095488 
 
 22.1811 
 
 7.8944 
 
 438 
 
 191844 
 
 84027672 
 
 20.9284 
 
 7.5944 
 
 493 
 
 243049 
 
 119823157 
 
 22.2036 
 
 7.8998 
 
 439 
 
 192721 
 
 846045 1 9 
 
 20.9523 
 
 7.6001 
 
 494 
 
 244036 
 
 120553784 
 
 22.2261 
 
 7.9051 
 
 440 
 
 193600 
 
 85184000 
 
 20.9762 
 
 7.6059 
 
 495 
 
 245025 
 
 121287375 
 
 22.2486 
 
 7.9105 
 
 441 
 
 194481 
 
 85766121 
 
 21.0000 
 
 7.6117 
 
 496 
 
 246016 
 
 122023936 
 
 22.2711 
 
 7.9153 
 
 442 
 
 195364 
 
 86350888 
 
 21 .0238 
 
 7.6174 
 
 497 
 
 247009 
 
 122763473 
 
 22.2935 
 
 7.9211 
 
 443 
 
 196249 
 
 86938307 
 
 21 0476 
 
 7.6232 
 
 498 
 
 248004 
 
 123505992 
 
 22.3159 
 
 7.9264 
 
 444 
 
 197136 
 
 87528384 
 
 21.0713 
 
 7.6289 
 
 499 
 
 249001 
 
 124251499 
 
 22.3383 
 
 7.9317 
 
 445 
 
 198025 
 
 88121125 
 
 21.0950 
 
 7.6346 
 
 500 
 
 250000 
 
 125000000 
 
 22.3607 
 
 7.9370 
 
 446 
 
 198916 
 
 88716536 
 
 21.1187 
 
 7.6403 
 
 501 
 
 251C01 
 
 125751501 
 
 22.3830 
 
 7.9423 
 
 447 
 
 199309 
 
 893 1 4623 
 
 21.1424 
 
 7.6460 
 
 502 
 
 257C04 
 
 126506008 
 
 22 4054 
 
 7.9476 
 
 443 
 
 200704 
 
 89915392 
 
 21.1660 
 
 7.6517 
 
 5u3 
 
 253009 
 
 127263527 
 
 22.4277 
 
 7.9523 
 
 449 
 
 201601 
 
 90518849 
 
 21.1896 
 
 7.6574 
 
 504 
 
 254016 
 
 128024064 
 
 22.4499 
 
 7.9581 
 
 450 
 
 202500 
 
 91125000 
 
 21.2132 
 
 7.6631 
 
 505 
 
 255025 
 
 128787625 
 
 22.-'.722 
 
 7.9634 
 
 451 
 
 203401 
 
 91733851 
 
 21.2368 
 
 7.6688 
 
 506 
 
 256036 
 
 129554216 
 
 22.4944 
 
 7.9686 
 
 452 
 
 204304 
 
 92345408 
 
 21.2603 
 
 7.6744 
 
 507 
 
 257049 
 
 130323843 
 
 22.5167 
 
 79739 
 
 453 
 
 205209 
 
 92959677 
 
 21.2838 
 
 7.6800 
 
 508 
 
 258064 
 
 131096512 
 
 22.5389 
 
 7.9791 
 
 454 
 
 206116 
 
 93576664 
 
 21.3073 
 
 7.6857 
 
 509 
 
 259081 
 
 131872229 
 
 22.5610 
 
 7-9843 
 
 455 
 
 207025 
 
 94196375 
 
 21.3307 
 
 7.6914 
 
 510 
 
 260100 
 
 132651000 
 
 22.5832 
 
 7.9896 
 
 456 
 
 207936 
 
 94818816 
 
 21.3542 
 
 7.6970 
 
 511 
 
 261121 
 
 133432331 
 
 22.6053 
 
 7.9948 
 
 457 
 
 203849 
 
 95443993 
 
 21.3776 
 
 7.7026 
 
 512 
 
 262144 
 
 134217728 
 
 22.6274 
 
 8.COOO 
 
 458 
 
 209764 
 
 96071912 
 
 2 1 .4009 
 
 7.7082 
 
 513 
 
 263169 
 
 1 35005697 
 
 22.6495 
 
 8.0052 
 
 459 
 
 210681 
 
 96702579 
 
 21.4243 
 
 7.7138 
 
 514 
 
 264196 
 
 135796744 
 
 22.6716 
 
 8.0104 
 
 <60 
 
 211600 
 
 97336000 
 
 21.4476 
 
 7.7194 
 
 515 
 
 265225 
 
 136590875 
 
 22.6936 
 
 8.0156 
 
 461 
 
 212521 
 
 97972181 
 
 21.4709 
 
 7.7250 
 
 516 
 
 266256 
 
 137388096 
 
 22.7156 
 
 8.0208 
 
 462 
 
 213444 
 
 98611128 
 
 21.4942 
 
 7.7306 
 
 517 
 
 267289 
 
 138138413 
 
 22.7376 
 
 8.0260 
 
 463 
 
 214369 
 
 99252847 
 
 21.5174 
 
 7.7362 
 
 518 
 
 268324 
 
 138991832 
 
 22.7596 
 
 8.0311 
 
 464 
 
 215296 
 
 99897344 
 
 21.5407 
 
 7.7418 
 
 519 
 
 269361 
 
 139798359 
 
 22.7816 
 
 8.0363 
 
 465 
 
 216225 
 
 100544625 
 
 21.5639 
 
 7.7473 
 
 520 
 
 270400 
 
 140608000 
 
 22.8035 
 
 8.0413 
 
 466 
 
 217156 
 
 101194696 
 
 21.5870 
 
 7.7529 
 
 521 
 
 271441 
 
 141420761 
 
 22.8254 
 
 8.0466 
 
 467 
 
 218039 
 
 101847563 
 
 21.6102 
 
 7.7584 
 
 522 
 
 272484 
 
 142236648 
 
 22.8473 
 
 8.0517 
 
 468 
 
 219024 
 
 102503232 
 
 21.6333 
 
 7.7639 
 
 523 
 
 273529 
 
 143055667 
 
 22.8692 
 
 80569 
 
 469 
 
 219961 
 
 103161709 
 
 21.6564 
 
 7.7695 
 
 524 
 
 274576 
 
 143877824 
 
 22.8910 
 
 8.0620 
 
 470 
 
 220900 
 
 103823000 
 
 21.6795 
 
 7.7750 
 
 525 
 
 275625 
 
 144703125 
 
 22.9129 
 
 8.0671 
 
 471 
 
 221341 
 
 104437111 
 
 21.7025 
 
 7.7805 
 
 526 
 
 276676 
 
 145531576 
 
 22.9347 
 
 8.0723 
 
 472 
 
 222734 
 
 105154048 
 
 21.7256 
 
 7.7860 
 
 527 
 
 277729 
 
 146363183 
 
 22.9565 
 
 8.0774 
 
 473 
 
 223729 
 
 105823317 
 
 21.7486 
 
 7.7915 
 
 528 
 
 278784 
 
 147197952 
 
 22.9783 
 
 8.0825 
 
 474 
 
 224576 
 
 106496424 
 
 21.7715 
 
 7.7970 
 
 529 
 
 279841 
 
 148035889 
 
 23.0000 
 
 8.0876 
 
 475 
 
 225625 
 
 107171875 
 
 21 7945 
 
 7.8025 
 
 530 
 
 280900 
 
 148877000 
 
 23.0217 
 
 8.0927 
 
 476 
 
 226576 
 
 107850176 
 
 21.8174 
 
 7.8079 
 
 531 
 
 281961 
 
 149721291 
 
 23.0434 
 
 8.0978 
 
 477 
 
 227529 
 
 108531333 
 
 21.8403 
 
 7.8134 
 
 532 
 
 283024 
 
 1 50568768 
 
 23.0651 
 
 8.1028 
 
 478 
 
 228484 
 
 109215352 
 
 21 8632 
 
 7.8188 
 
 533 
 
 284089 
 
 151419437 
 
 23.0868 
 
 8.1079 
 
 479 
 
 229441 
 
 109902239 
 
 2K8861 
 
 7.8243 
 
 534 
 
 285156 
 
 152273304 
 
 23.1084 
 
 8.1130 
 
 480 
 
 230400 
 
 1 1 0592000 
 
 21.9089 
 
 7.8297 
 
 535 
 
 286225 
 
 153130375 
 
 23.1301 
 
 8.1180 
 
 481 
 
 231361 
 
 111284641 
 
 21.9317 
 
 7.8352 
 
 536 
 
 287296 
 
 1 53990656 
 
 23.1517 
 
 8.1231 
 
 482 
 
 232324 
 
 111980168 
 
 21.9545 
 
 7.8406 
 
 537 
 
 288369 
 
 154854153 
 
 23.1733 
 
 8.1281 
 
 483 
 
 233289 
 
 112678587 
 
 21.9773 
 
 7.8460 
 
 538 
 
 289444 
 
 155720872 
 
 23.1948 
 
 8.1332 
 
 484 
 
 234256 
 
 1 13379904 
 
 22.0000 
 
 7.8514 
 
 539 
 
 290521 
 
 156590319 
 
 23.2164 
 
 8.1382 
 
USEFUL TABLES FOE MARINE ENGINEERS 
 
 235 
 
 No. 
 
 540 
 541 
 542 
 543 
 544 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 29 1 600 
 292681 
 293764 
 294349 
 295936 
 
 157464000 
 158340421 
 1 59220083 
 160103007 
 160989184 
 
 23.2379 
 23.2594 
 23.2809 
 23.3024 
 23.3238 
 
 8.1433 
 8.1483 
 8.1533 
 8.1583 
 8.1633 
 
 595 
 596 
 597 
 598 
 599 
 
 354025 
 355216 
 356409 
 357604 
 358801 
 
 2106448/5 
 211708736 
 212776173 
 213847192 
 214921799 
 
 24.3926 
 24.4131 
 24.4336 
 24.4540 
 24.4745 
 
 8.4108 
 8.4155 
 8.4202 
 8.4249 
 8.4296 
 
 545 
 
 546 
 547 
 543 
 549 
 
 297025 
 298116 
 299209 
 300304 
 301401 
 
 161378625 
 162771336 
 163667323 
 164566592 
 165469149 
 
 23.3452 
 23.3666 
 23.3880 
 23.4094 
 23.4307 
 
 8.1683 
 8.1733 
 8.1783 
 8.1833 
 8.1882 
 
 600 
 601 
 602 
 603 
 604 
 
 360000 
 361201 
 362404 
 363609 
 364816 
 
 216000000 
 217081801 
 218167208 
 219256227 
 220348864 
 
 24.4949 
 24.5153 
 24.5357 
 24.5561 
 24.5764 
 
 8.4343 
 8.4390 
 8.4437 
 8.4484 
 8.4530 
 
 550 
 551 
 552 
 553 
 554 
 
 302500 
 303601 
 304704 
 305809 
 306916 
 
 166375000 
 
 167234151 
 163196608 
 169112377 
 170031464 
 
 23.4521 
 23.4734 
 23.4947 
 23.5160 
 23.5372 
 
 8.1932 
 8.1982 
 8.2031 
 8.2081 
 8.2130 
 
 605 
 606 
 607 
 608 
 609 
 
 366025 
 367236 
 363449 
 369664 
 370881 
 
 221445125 
 222545016 
 223648543 
 224755712 
 225866529 
 
 24.5967 
 24.6171 
 24.6374 
 24.6577 
 24.6779 
 
 8.4577 
 8.4623 
 8.4670 
 8.4716 
 8.4763 
 
 555 
 556 
 557 
 
 553 
 559 
 
 308025 
 309136 
 310249 
 3 1 1 364 
 312481 
 
 170953875 23.5584 
 17187961623.5797 
 172803693 23.6003 
 173741112 23.6220 
 17467687923.6432 
 
 8.2180 
 8.2229 
 8.2278 
 8.2327 
 8.2377 
 
 610 
 611 
 612 
 613 
 614 
 
 372100 
 373321 
 374544 
 375769 
 376996 
 
 226981000 
 228099131 
 229220928 
 230346397 
 231415544 
 
 24.6982 
 24.7184 
 24.7386 
 24.7588 
 24.7790 
 
 8.4809 
 8.4856 
 8.4902 
 8.4948 
 8.4994 
 
 560 
 561 
 D62 
 563 
 564 
 
 313600 17561600023.6643 
 314721 176553431:23.6354 
 3 1 5844: 1 77504323 23.7065 
 3 1 6969 1 78453547 23.7276 
 318096 17940614423.7487 
 
 8.2426 
 8.2475 
 8.2524 
 8.2573 
 8.2621 
 
 615 
 616 
 617 
 618 
 619 
 
 378225 
 379456 
 380639 
 381924 
 383161 
 
 232608375 
 233744896 
 234885113 
 236029032 
 237176659 
 
 24.7992 
 24.8193 
 24.8395 
 24.8596 
 24.8797 
 
 8.5040 
 8.5086 
 8.5132 
 8.5178 
 8.5224 
 
 565 
 566 
 '>67 
 568 
 569 
 
 319225 
 
 320356 
 321489 
 322624 
 323761 
 
 180362125 23.7697 
 18132149623.7903 
 182234263 23.0118 
 1P3250432 23.8323 
 .8422000923.8537 
 
 8.2670 
 8.2719 
 8.2763 
 8.2816 
 8.2865 
 
 620 
 621 
 622 
 623 
 624 
 
 384400 
 385641 
 336884 
 383129 
 389376 
 
 238328000 
 239483061 
 240641848 
 241804367 
 242970624 
 
 24 8998 
 249199 
 24.9399 
 24.9600 
 24.9800 
 
 8.5270 
 8.5316 
 8.5362 
 8.5408 
 8.5453 
 
 570 
 571 
 572 
 573 
 574 
 
 324900 
 326041 
 327184 
 328329 
 329476 
 
 18519300023.8747 
 186169411 23.8956 
 187149243:23.9165 
 18313251723.9374 
 18911922423.9583 
 
 8.2913 
 8.2962 
 8.3010 
 8.3059 
 8.3107 
 
 625 
 626 
 627 
 628 
 629 
 
 390625 
 391876 
 393129 
 394384 
 395641 
 
 244140625 
 245314376 
 246491833 
 247673152 
 248858189 
 
 25.0000 
 25.0200 
 25.0400 
 25.0599 
 25.0799 
 
 8.5499 
 8.5544 
 85590 
 8.5635 
 8.5681 
 
 575 
 576 
 
 577 
 578 
 579 
 
 330625 
 331776 
 332929 
 334084 
 335241 
 
 190109375 
 191102976 
 192100033 
 193100552 
 194104539 
 
 23.9792 
 24.0000 
 24.0208 
 24.0416 
 24.0624 
 
 8.3155 
 8.3203 
 8.3251 
 8.3300 
 8.3348 
 
 630 
 631 
 632 
 633 
 634 
 
 396900 
 398161 
 399424 
 400639 
 401956 
 
 250047000 
 251239591 
 252435968 
 253636137 
 254840104 
 
 25.0998 
 25.1197 
 25.1396 
 25.1595 
 25.1794 
 
 8.5726 
 8.5772 
 8.5817 
 8.5862 
 8.5907 
 
 580 
 581 
 582 
 583 
 584 
 
 336400 
 337561 
 338724 
 339889 
 341056 
 
 195112000 
 196122941 
 197137368 
 193155287 
 199176704 
 
 24.0832 
 24.1039 
 24.1247 
 24. 1 454 
 24.1661 
 
 8.3396 
 8.3443 
 8.3491 
 8.3539 
 8.3587 
 
 635 
 636 
 637 
 638 
 639 
 
 403225 
 404496 
 405769 
 407044 
 40832 1 
 
 256047875 
 257259456 
 258474853 
 259694072 
 260917119 
 
 25.1992 
 25.2190 
 25.2389 
 25.2587 
 25.2784 
 
 8.5952 
 8.5997 
 8.6043 
 8.6083 
 8.6132 
 
 585 
 
 536 
 587 
 533 
 589 
 
 342225 
 343396 
 344569 
 345744 
 34692 1 
 
 200201625 
 201230056 
 202262003 
 203297472 
 204336469 
 
 24.1868 
 24.2074 
 24.2281 
 24.2437 
 24.2693 
 
 8.3634 
 8.3682 
 8.3730 
 8.3777 
 8.3825 
 
 640 
 641 
 642 
 643 
 644 
 
 409600 
 410881 
 412164 
 413449 
 414736 
 
 262144000 
 263374721 
 264609288 
 265847707 
 267089934 
 
 25.2982 
 25.3180 
 25.3377 
 25.3574 
 25.37>2 
 
 8.6177 
 8.6222 
 8.6267 
 8.6312 
 8.6357 
 
 590 
 591 
 592 
 593 
 594 
 
 343100 
 349281 
 350464 
 351649 
 352836 
 
 205379000 
 206425071 
 207474688 
 208527857 
 209584584 
 
 24.2899 
 243105 
 24.331 1 
 24.3516 
 24.3721 
 
 8.3872 
 8.3919 
 8.3967 
 8.4014 
 8.4061 
 
 645 
 646 
 647 
 648 
 649 
 
 416025 
 417316 
 418609 
 419904 
 421201 
 
 268336125 
 269586136 
 270840n?3 
 272097792 
 273359449 
 
 25.3969 
 25.4165 
 25.4362 
 25.4558 
 254755 
 
 8.6401 
 8.6446 
 86490 
 86535 
 8.6579 
 
236 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 No. 
 
 650 
 651 
 652 
 653 
 654 
 
 Square. 
 
 422500 
 423801 
 425104 
 426409 
 427716 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 ~705 
 706 
 707 
 708 
 709 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 274625000 
 27 389445 1 
 277167808 
 278445077 
 279726264 
 
 25.4951 
 25.5147 
 25.5343 
 25.5539 
 25.5734 
 
 8.6624 
 8.6668 
 8.6713 
 8.6757 
 8.6801 
 
 497025 
 498436 
 499849 
 501264 
 502681 
 
 350402625 
 351895816 
 353393243 
 354894912 
 356400829 
 
 26.5518 
 26.5707 
 26.5895 
 26.6083 
 26.6271 
 
 8.9001 
 8.9043 
 8.9085 
 8.9127 
 8.9169 
 
 655 
 656 
 657 
 658 
 659 
 
 429025 
 430336 
 431649 
 432964 
 434281 
 
 281011375 
 282300416 
 283593393 
 284890312 
 286191179 
 
 25.5930 
 25.6125 
 25.6320 
 25.6515 
 25.6710 
 
 8.6845 
 8.6890 
 8.6934 
 8.6978 
 8.7022 
 
 710 
 711 
 712 
 713 
 714 
 
 504100 
 505521 
 506944 
 508369 
 509796 
 
 357911000 
 359425431 
 360944128 
 362467097 
 363994344 
 
 26.6458 
 26.6646 
 26.6833 
 26.7021 
 26.7208 
 
 8.9211 
 8.9253 
 8.9295 
 8.9337 
 8.9378 
 
 660 
 661 
 662 
 663 
 664 
 
 435600 
 43692 1 
 438244 
 439569 
 440896 
 
 287496000 
 288804781 
 290117528 
 291434247 
 292754944 
 
 25.6905 
 25.7099 
 25.7294 
 25.7483 
 25.7682 
 
 8.7066 
 8.7110 
 8.7154 
 8.7198 
 8.7241 
 
 715 
 716 
 717 
 718 
 719 
 
 511225 
 512656 
 5 1 4089 
 515524 
 516961 
 
 365525875 
 367061696 
 366601813 
 370146232 
 371694959 
 
 26.7395 
 26.7582 
 26.7769 
 26.7955 
 26.8142 
 
 8.9420 
 8.9462 
 8.9503 
 8.9545 
 8.9587 
 
 665 
 666 
 667 
 663 
 669 
 
 442225 
 443556 
 444889 
 446224 
 447561 
 
 294079625 
 295408296 
 296740963 
 298077632 
 299418309 
 
 25.7876 
 25.8070 
 25 8263 
 25.8457 
 25.8650 
 
 8.7285 
 o.7329 
 87373 
 8. 7< 16 
 8.7460 
 
 720 
 
 721 
 722 
 723 
 724 
 
 518400 
 519841 
 521284 
 522729 
 524176 
 
 373248000 
 374805361 
 376367048 
 377933067 
 379503424 
 
 26.8328 
 26.8514 
 26.8701 
 26.8887 
 26.9072 
 
 8.9628 
 8.9670 
 8.9711 
 8.9752 
 8.9794 
 
 670 
 671 
 672 
 673 
 674 
 
 448900 
 450241 
 451584 
 452929 
 454276 
 
 300763000 
 302111711 
 303464448 
 304821217 
 306182024 
 
 25.8844 
 25.9037 
 25 9230 
 25.9422 
 25.9615 
 
 8.7503 
 8.7547 
 8.7590 
 3.7634 
 8.7677 
 
 725 
 726 
 727 
 728 
 729 
 
 525625 
 527076 
 528529 
 529984 
 531441 
 
 381078125 
 382657176 
 384240583 
 385828352 
 387420489 
 
 26.9258 
 26 9444 
 26.9629 
 26.9815 
 27.0000 
 
 8.9835 
 8.9876 
 8.9918 
 8.9959 
 90000 
 
 675 
 676 
 677 
 678 
 679 
 
 455625 
 456976 
 458329 
 459684 
 461041 
 
 307546875 
 308915776 
 310288733 
 311665752 
 313046839 
 
 25.9803 
 26 0000 
 26.0192 
 26.0384 
 26.0576 
 
 8.7721 
 87764 
 8.7807 
 8.7850 
 8.7893 
 
 730 
 731 
 732 
 733 
 734 
 
 532900 
 534361 
 535824 
 537289 
 538756 
 
 389017000 
 390617891 
 392223168 
 393832837 
 395446904 
 
 27.0185 
 27.0370 
 27.0555 
 27.0740 
 27.0924 
 
 9.0041 
 9.0082 
 9.0123 
 9.0164 
 9.0205 
 
 680 
 681 
 682 
 683 
 684 
 
 462400 
 463761 
 465124 
 466489 
 467856 
 
 314432000 
 315821241 
 317214569 
 318611987 
 320013504 
 
 26.0768 
 26 0960 
 26.1151 
 26.1343 
 26.1534 
 
 8.7937 
 87980 
 8.8023 
 8.8066 
 8.8109 
 
 735 
 736 
 737 
 733 
 739 
 
 540225 
 541696 
 543 1 69 
 544644 
 546121 
 
 397065375 
 398688256 
 400315553 
 401947272 
 403583419 
 
 27.1109 
 27.1293 
 27.1477 
 27.1662 
 27.1846 
 
 9.0246 
 9.0287 
 9.0328 
 90369 
 9.0410 
 
 685 
 686 
 687 
 688 
 689 
 
 469225 
 470596 
 47 1 969 
 473344 
 474721 
 
 321419125 
 322828856 
 324242703 
 325660672 
 327082769 
 
 26.1725 
 26 1916 
 26.2107 
 26.2298 
 26.2488 
 
 88152 
 88194 
 8.8237 
 88280 
 8.8323 
 
 740 
 741 
 742 
 743 
 744 
 
 547600 
 54908 1 
 550564 
 552049 
 553536 
 
 40522400C 
 406869021 
 408518488 
 410172407 
 411830704 
 
 27.2029 
 27.2213 
 27.2397 
 27.2560 
 27.2764 
 
 9.0450 
 90491 
 9.0532 
 9.0572 
 9.0613 
 
 690 
 691 
 692 
 693 
 694 
 
 476100 
 477481 
 478364 
 480249 
 481636 
 
 328509000 
 329939371 
 331373888 
 332812557 
 334255384 
 
 26 2679 
 26.2869 
 26.3059 
 26.3249 
 26.3439 
 
 8.8366 
 6.8408 
 88451 
 8.8493 
 8.8536 
 
 745 
 746 
 747 
 74S 
 749 
 
 555025 
 556516 
 558009 
 559504 
 561001 
 
 413493625 
 415160936 
 416832723 
 418508992 
 420189749 
 
 27 2947 
 27.3130 
 27.3313 
 27.3496 
 27.3679 
 
 9.0654 
 9.0694 
 90735 
 9.0775 
 9.0816 
 
 695 
 696 
 697 
 693 
 699 
 
 483025 
 484416 
 485809 
 487204 
 488601 
 
 335702375 
 337153536 
 338608873 
 340068392 
 341532099 
 
 26.3629 
 26.3818 
 26.4008 
 26.4197 
 26.4386 
 
 8.8578 
 8.8621 
 8.8663 
 8.8706 
 8.8748 
 
 750 
 751 
 752 
 753 
 754 
 
 562500 
 564001 
 565504 
 567009 
 5685 1 6 
 
 4218750CO 
 423564751 
 425259008 
 42695777/ 
 428661061 
 
 273861 
 27.404< 
 27.4226 
 27.4408 
 27.4591 
 
 9.0856 
 90896 
 9.0937 
 9.0977 
 9.1017 
 
 700 
 701 
 702 
 703 
 704 
 
 490000 
 491401 
 492804 
 494209 
 495616 
 
 343000000 
 344472101 
 345948408 
 347428927 
 348913664 
 
 26.4575 
 26 4764 
 264953 
 26.5141 
 765330 
 
 8.8790 
 88833 
 88875 
 88917 
 88959 
 
 755 
 756 
 757 
 758 
 759 
 
 570025 
 571536 
 573049 
 574564 
 576081 
 
 430368875 
 432081216 
 433798093 
 435519512 
 437245479 
 
 27.4/73 
 27.4955 
 27 5136 
 27.5318 
 27.5500 
 
 91057 
 9 1098 
 9.1138 
 9 1178 
 9.1218 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 237 
 
 No 
 
 760 
 76 
 762 
 763 
 764 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 57/60U 
 579121 
 580644 
 532169 
 533696 
 
 438976000 
 J4407I1081 
 442450728 
 444194947 
 445943744 
 
 27.5681 
 27.5862 
 27.6043 
 27.6225 
 27.6405 
 
 9.1258 
 9.1298 
 9.1338 
 9.1378 
 9.1418 
 
 815 
 816 
 817 
 818 
 819 
 
 664225 
 665856 
 667489 
 669124 
 670761 
 
 541343375 
 543338496 
 545338513 
 547343432 
 549353259 
 
 28.5482 
 28.5657 
 28.5832 
 28.6007 
 28.6182 
 
 9.3408 
 9.3447 
 9.3485 
 9.3523 
 9.3561 
 
 765 
 766 
 767 
 763 
 769 
 
 535225 
 536736 
 533289 
 539324 
 591361 
 
 447697125 
 449455096 
 451217663 
 452984832 
 454756609 
 
 27.6586 
 27.6767 
 27.6948 
 27.7128 
 27.7308 
 
 9.1458 
 9.1498 
 9.1537 
 9.1577 
 9.1617 
 
 820 
 821 
 822 
 823 
 824 
 
 672400 
 674041 
 675684 
 677329 
 678976 
 
 551368000 
 553387661 
 555412248 
 557441767 
 559476224 
 
 28.6356 
 28.6531 
 28.6705 
 
 28.688C 
 28.7054 
 
 9.3599 
 9.3637 
 9.3675 
 9.3713 
 9.3751 
 
 770 
 771 
 772 
 773 
 774 
 
 592903 
 594441 
 595984 
 597529 
 599076 
 
 456533000 
 458314011 
 460099648 
 461889917 
 463684824 
 
 27.7489 
 27.7669 
 27.7849 
 27.8029 
 27.8209 
 
 9.1657 
 9.1696 
 9.1736 
 9.1775 
 9.1815 
 
 825 
 826 
 827 
 823 
 829 
 
 680625 
 632276 
 633929 
 685584 
 687241 
 
 561515625 
 563559976 
 565609283 
 567663552 
 569722789 
 
 28.7228 
 28.7402 
 28.7576 
 28.775C 
 28.7924 
 
 9.3789 
 9.3827 
 9.3865 
 9.3902 
 9.3940 
 
 775 
 
 776 
 777 
 778 
 779 
 
 630625 
 632176 
 633729 
 635234 
 636341 
 
 465434375 
 467283576 
 469097433 
 470910952 
 472729139 
 
 27.8383 
 27.8563 
 27.8747 
 27.8927 
 27.9106 
 
 9.1855 
 9.1894 
 9.1933 
 9.1973 
 9.2012 
 
 830 
 831 
 832 
 833 
 834 
 
 688900 
 690561 
 692224 
 693889 
 695556 
 
 571787000 
 573856191 
 575930368 
 578009537 
 580093704 
 
 28.8097 
 28.8271 
 28.8444 
 28.8617 
 28.8791 
 
 9.3978 
 9.4016 
 9.4053 
 9.4091 
 9.4129 
 
 733 
 731 
 782 
 733 
 784 
 
 603403 
 639961 
 611524 
 613039 
 614656 
 
 474552000 
 476379541 
 478211763 
 430043637 
 431890304 
 
 27.9285 
 27.9464 
 27.9643 
 27.9821 
 28.0000 
 
 9.2052 
 9.2091 
 9.2130 
 9.2170 
 9.2209 
 
 835 
 836 
 837 
 833 
 839 
 
 697225 
 698896 
 700569 
 702244 
 703921 
 
 582182875 
 584277056 
 586376253 
 588480472 
 590589719 
 
 28.8964 
 28.9137 
 28.9310 
 28.9482 
 28.9655 
 
 9.4166 
 9.4204 
 9.4241 
 9.4279 
 9.4316 
 
 785 
 
 786 
 787 
 733 
 739 
 
 616225 
 617796 
 619369 
 620944 
 622521 
 
 483736625 
 435537656 
 437443403 
 439303372 
 491169069 
 
 28.0179 
 28.03 7 
 28.0535 
 23.0713 
 28.0891 
 
 9.2243 
 9.2287 
 9.2326 
 9.2365 
 9.2404 
 
 840 
 841 
 842 
 843 
 844 
 
 705600 
 
 707281 
 708964 
 710649 
 712336 
 
 592704000 
 594323321 
 596947688 
 599077107 
 601211584 
 
 28.9828 
 29.0000 
 29.0172 
 29.0345 
 29.0517 
 
 9.4354 
 9.4391 
 9.4429 
 9.4466 
 9.4503 
 
 793 
 
 791 
 792 
 793 
 794 
 
 624100 
 625631 
 627264 
 623349 
 630436 
 
 493039000 
 494913*71 
 496793083 
 493677257 
 500566184 
 
 28.1069 
 28.1247 
 28.1425 
 23.1603 
 28. 1 780 
 
 9.2443 
 9.2482 
 9.2521 
 ~.2560 
 9.2599 
 
 845 
 846 
 847 
 843 
 849 
 
 714025 
 715716 
 717409 
 719104 
 720801 
 
 603351125 
 605495736 
 607645423 
 609800192 
 611960049 
 
 29.0689 
 29.0861 
 29.1033 
 29.1204 
 29.1376 
 
 9.4541 
 9.4578 
 9.4615 
 9.4652 
 9.4690 
 
 795 
 796 
 797 
 793 
 799 
 
 632025 
 633616 
 635209 
 636304 
 638401 
 
 502459875 
 504353336 
 5062:1573 
 508160592 
 510082399 
 
 28.1957 
 28.2135 
 28.2312 
 28.2489 
 28.2666 
 
 9.2638 
 9.2677 
 9.2716 
 9.2754 
 9.2793 
 
 850 
 851 
 852 
 853 
 854 
 
 722500 614125000 29.1548 
 724201 616295051 29.1719 
 725904 618470208 29.1890 
 727609 620650477; 29.2062 
 7293 1 6 622835864 29.2233 
 
 9.4727 
 9.4764 
 9.4301 
 9.-+83S 
 9.4875 
 
 800 
 801 
 802 
 803 
 804 
 
 640000 5 1 2000000 
 641601 513922401 
 643204 515849608 
 644809 517781627 
 646416519718464 
 
 28.2843 
 28.3019 
 28.3196 
 28.3373 
 28.3549 
 
 9.2832 
 9.2870 
 9.2909 
 9.2948 
 9.2986 
 
 855 7310251 
 856 732736 
 857 734449 
 858 736164 
 859 737881 
 
 625026375 29.2404 
 62722201629.2575 
 629422793 29.2746 
 63162871229.2916 
 633839779 29.3087 
 
 9.4912 
 9.4949 
 9.4986 
 9.5023 
 9.5060 
 
 805 
 806 
 807 
 808 
 809 
 
 643025 
 649636 
 651249 
 652864 
 654431 
 
 52166012528.37259.3025 
 523606616 28.3901 9.3063 
 525557943 28.4077 9.3102 
 52751411228.42539.3140 
 52947512928.44299.3179 
 
 860 739600 636056000 
 861 741321 638277381 
 862 743044 640503928 
 863 744769 642735647 
 864 746496 644972544 
 
 29.3258 
 29.3428 
 29.3598 
 29.3769 
 29.3939 
 
 9.5097 
 9.5134 
 9.5171 
 9.5207 
 9.5244 
 
 810 
 811 
 812 
 813 
 814 
 
 656100 
 657721 
 659344 
 660969 
 662596 
 
 53144100028.46059.3217 
 533411 73 1;28.4781 9.3255 
 535387328*28.4956 9.3294 
 537367797!28.5132 9.3332 
 539353 1 441 28.5307 9.3370 
 
 865 
 866 
 867 
 868 
 869 
 
 748225 647214625 29.4109 
 749956 649461896 29.4279 
 751689651714363:29.4449 
 75342465397203229.4618 
 755 161 1656234909129.4783 
 
 9.5231 
 9.5317 
 9.5354 
 9.5391 
 9.5427 
 
238 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 No 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root . 
 
 Xo. 
 
 ^925 
 926 
 927 
 928 
 929 
 
 Square 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 870 
 
 87! 
 872 
 873 
 874 
 
 756900 
 758641 
 760384 
 762 1 29 
 763876 
 
 658503000 
 6607763 1 1 
 603054848 
 665338617 
 667627624 
 
 29.4958 
 29.5127 
 29.5296 
 29.5466 
 29.5635 
 
 9.5464 
 9.5501 
 9.5537 
 9.5574 
 9.5610 
 
 855625 
 857476 
 859329 
 861184 
 863041 
 
 791453125 
 794022776 
 796597983 
 799178752 
 801765089 
 
 30.4138 
 30.4302 
 30.4467 
 30.4631 
 30.4795 
 
 9.7435 
 9.7470 
 9.7505 
 9.7540 
 9.7575 
 
 875 
 876 
 877 
 878 
 879 
 
 765625 
 767376 
 769129 
 770884 
 772641 
 
 669921875 
 672221376 
 674526133 
 676836152 
 679151439 
 
 29.5804 
 29.5973 
 29.6142 
 29.63 1 
 29.6479 
 
 9.5647 
 9.5683 
 9.5719 
 9.5756 
 9.5792 
 
 930 
 931 
 932 
 933 
 934 
 
 864900 
 866761 
 868624 
 870489 
 872356 
 
 S0435700C 
 806954491 
 809557568 
 812166237 
 814780504 
 
 30.4959 
 30.5123 
 30.5287 
 30.5450 
 30.5614 
 
 9.7610 
 9.7645 
 9.7680 
 9.7715 
 9.7750 
 
 880 
 881 
 882 
 883 
 884 
 
 774400 
 776161 
 777924 
 779689 
 781456 
 
 681472000 
 683797841 
 686128968 
 688465387 
 690807104 
 
 29.6648 
 29.6816 
 29.6985 
 29.7153 
 29.7321 
 
 9.5828 
 9.5865 
 9.5901 
 9.5937 
 9.5973 
 
 935 
 936 
 937 
 938 
 939 
 
 874225 
 876096 
 877969 
 879844 
 881721 
 
 817400375 
 820025856 
 822656953 
 825293672 
 827936019 
 
 30.5778 
 30.5941 
 30.6105 
 30.6263 
 30.6431 
 
 9.7785 
 9.7819 
 9.7854 
 9.7889 
 9.7924 
 
 885 
 
 886 
 887 
 883 
 889 
 
 783225 
 784996 
 786769 
 788544 
 790321 
 
 693154125 
 695506456 
 697864103 
 700227072 
 702595369 
 
 29.748? 
 29.7658 
 29.7825 
 29.7993 
 29.8161 
 
 9.6010 
 9.6046 
 9.6082 
 9.6118 
 9.6154 
 
 940 
 941 
 942 
 943 
 944 
 
 833600 
 835481 
 837364 
 839249 
 891136 
 
 830584000 
 833237621 
 835896888 
 838561807 
 841232384 
 
 30.6594 
 30.6757 
 30.6920 
 30.7083 
 30.7246 
 
 9.7959 
 9.7993 
 9.8028 
 9.8063 
 9.8097 
 
 890 
 891 
 892 
 893 
 894 
 
 792100 
 793881 
 795664 
 797449 
 799236 
 
 704969000 
 707347971 
 709732288 
 712121957 
 714516984 
 
 29.8329 
 29.8496 
 29.8664 
 29.883 1 
 29.8998 
 
 9.6190 
 9.6226 
 9.6262 
 9.6298 
 9.6334 
 
 945 
 946 
 947 
 943 
 949 
 
 893025 
 894916 
 896809 
 898704 
 900601 
 
 843908625 
 846590536 
 849278123 
 851971392 
 854670349 
 
 30.7409 
 30.757! 
 30.7734 
 30.7896 
 30.8058 
 
 9.8132 
 9.8167 
 9.8201 
 9.8236 
 9.8270 
 
 895 
 896 
 897 
 898 
 899 
 
 801025 
 802816 
 804609 
 806404 
 808201 
 
 716917375 
 719323136 
 721734273 
 724150792 
 726572699 
 
 299166 
 29.9333 
 29.9500 
 29.9666 
 29.9833 
 
 9.6370 
 
 9.6406 
 9.6442 
 9.6477 
 9.6513 
 
 950 
 951 
 952 
 953 
 954 
 
 902500 
 904401 
 906304 
 908209 
 910116 
 
 857375000 
 86008535 1 
 862801408 
 865523177 
 868250664 
 
 30.8221 
 30.8383 
 30.8545 
 30.8707 
 30.8869 
 
 9.8305 
 9.8339 
 9.8374 
 9.8408 
 9.8443 
 
 900 
 901 
 902 
 903 
 904 
 
 810000 
 811801 
 813604 
 815409 
 817216 
 
 729000000 
 731432701 
 733870808 
 736314327 
 738763264 
 
 30.000C 
 30.0167 
 30.0333 
 30.0500 
 30.0666 
 
 9.6549 
 9.6585 
 9.6620 
 9.6656 
 9.6692 
 
 955 
 956 
 957 
 953 
 959 
 
 912025 870983875 
 913936873722816 
 915849876467493 
 917764879217912 
 919681 831974079 
 
 30.903 1 
 30.9192 
 30.9354 
 30.9516 
 30.9677 
 
 9.8477 
 9.8511 
 9.8546 
 9.8580 
 9.8614 
 
 905 
 906 
 907 
 908 
 909 
 
 819025 
 820836 
 822649 
 824464 
 826281 
 
 741217625 
 743677416 
 746142643 
 743613312 
 751089429 
 
 30.0832 
 30.099 
 30.1164 
 30.133C 
 30.1496 
 
 9.6727 
 9.6763 
 9.6799 
 9.6834 
 9.6870 
 
 960 
 961 
 962 
 963 
 964 
 
 921600 
 923521 
 925444 
 927369 
 92929C 
 
 884736000 
 887503681 
 890277128 
 893056347 
 895841344 
 
 30.9839 
 3 1 .0000 
 31.0161 
 31.0322 
 31.0483 
 
 9.8643 
 9.8683 
 9.8717 
 9.8751 
 9.8785 
 
 910 
 911 
 912 
 913 
 914 
 
 828100 
 82992 1 
 83 1 744 
 833569 
 835396 
 
 75357100C 
 756058031 
 758550523 
 761048497 
 763551944 
 
 30.1662 
 30.1825 
 30.1993 
 30.2159 
 30.2324 
 
 9.6905 
 9.6941 
 9.6976 
 9.7012 
 9.7047 
 
 965 
 966 
 967 
 963 
 969 
 
 931225 
 933156 
 935089 
 937024 
 938961 
 
 398632125 
 901428696 
 904231063 
 907039232 
 909853209 
 
 3 1 .0644 
 3 1 .0805 
 3 1 .0966 
 31.1127 
 31.1288 
 
 9.8819 
 9.8854 
 9.8888 
 9.8922 
 9.8956 
 
 915 
 916 
 917 
 918 
 919 
 
 837225 
 839056 
 840889 
 842724 
 844561 
 
 766060875 
 763575296 
 771095213 
 773620632 
 776151559 
 
 30.2490 
 30.2655 
 30.2S2C 
 30.2935 
 30.3150 
 
 9.7032 
 9.7113 
 9.7153 
 9.7183 
 9.7224 
 
 970 
 971 
 972 
 973 
 974 
 
 940900 
 942841 
 944784 
 946729 
 948676 
 
 912673000 
 915498611 
 918330048 
 921167317 
 924010424 
 
 31.1443 
 31.1609 
 3 1 . 1 769 
 31.1929 
 3 1 .2090 
 
 9.8990 
 9.9024 
 9.9058 
 9.9092 
 9.9126 
 
 920 
 921 
 922 
 923 
 924 
 
 846400 
 848241 
 850084 
 851929 
 853776 
 
 778688000 
 781229961 
 783777443 
 786330467 
 78&889024 
 
 30.3315 
 30.3480 
 30.3645 
 30.3809 
 30.3974 
 
 9.7259 
 9.7294 
 9.7329 
 9.7364 
 9.7400 
 
 975 
 976 
 977 
 978 
 979 
 
 950625 
 952576 
 954529i 
 956484' 
 95844 li 
 
 926859375 
 929714176 
 932574833 
 935441352 
 938313739 
 
 31.2250 
 31.2410 
 31.2570 
 31.2730 
 31.2890 
 
 99160 
 99194 
 9.9227 
 9.9261 
 9.9293 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 239 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 No. 
 
 Square. 
 
 Cube. 
 
 Sq. 
 Root. 
 
 Cube 
 Root. 
 
 "980 
 
 960400 
 
 941 192000 
 
 31.3050 
 
 9.9329 
 
 1033 
 
 1071225 
 
 1108717875 
 
 32.1714 
 
 10.1153 
 
 981 
 
 962361 
 
 944076141 
 
 31.3209 
 
 9.9363 
 
 1036 
 
 10732% 
 
 1111934656 
 
 32 1870 
 
 10 1186 
 
 932 
 983 
 
 964324 
 966289 
 
 946966168 
 949862087 
 
 31.3369 
 31.3528 
 
 9.93% 
 9.9430 
 
 1037 
 1038 
 
 1075369 1115157653 
 1077444 1 1 18386872 
 
 32.2025 
 32.2180 
 
 10J218 
 10 1251 
 
 984 
 
 968256 
 
 952763904 
 
 31.3688 
 
 9.9464 
 
 1039 
 
 1079521 
 
 1121622319 
 
 32.2335 
 
 10.1283 
 
 935 
 
 970225 
 
 955671625 
 
 31.3847 
 
 9.9497 
 
 1040 
 
 1081600 
 
 1124864000 
 
 32.2490 
 
 10.1316 
 
 986 
 
 972196 
 
 958585256 
 
 31.4006 
 
 9.9531 
 
 1041 
 
 1083681 
 
 1128111921 
 
 322645 
 
 10 1343 
 
 087 
 
 974169 
 
 96150430331.4166 
 
 9.9565 
 
 1042 
 
 1085764 
 
 1131366033 
 
 32.2800 
 
 10.1381 
 
 933 
 
 976144 
 
 964430272 
 
 31.4325 
 
 9.9598 
 
 1043 
 
 1087849 
 
 1134626507 
 
 32.2955 
 
 10.1413 
 
 939 
 
 978121 
 
 967361569 
 
 31.4484 
 
 9.%32 
 
 1044 
 
 1089936 
 
 1137893184 
 
 32.3110 
 
 10.1446 
 
 990 
 
 980100 
 
 970299000 
 
 31.4643 
 
 9.9666 
 
 1045 
 
 1092025 
 
 1141166125 
 
 32.3265 
 
 10.1478 
 
 991 
 
 932081 
 
 973242271 
 
 31.4802 
 
 9.9699 
 
 1046 
 
 1094116 
 
 1144445336 
 
 32.3419 
 
 10.1510 
 
 992 
 
 934064 
 
 976191438 
 
 31.4960 
 
 9.9733 
 
 1047 
 
 10%209 
 
 1147730323 
 
 32 3574 
 
 10.1543 
 
 993 
 
 936049 
 
 979146657 
 
 31.5119 
 
 9.9766 
 
 1043 
 
 1098304 
 
 1151022592 
 
 32.3723 
 
 10.1575 
 
 994 
 
 988036 
 
 932107784 
 
 31.5278 
 
 9.9800 
 
 1049 
 
 1100401 
 
 1 154320649 
 
 32.3883 
 
 10.1607 
 
 995 
 
 990025 
 
 935074875 
 
 31.5436 
 
 9.9833 
 
 1050 
 
 1 102500 
 
 1157625000 
 
 32.4037 
 
 10.1640 
 
 996 
 
 992016 
 
 933047936 
 
 31.5595 
 
 9.9366 
 
 1051 
 
 1104601 
 
 1160935651 
 
 32.4191 
 
 10.1672 
 
 997 
 
 994009 
 
 991026973 
 
 31.5753 
 
 9.9900 
 
 1052 
 
 1106704 
 
 1164252603 
 
 32.4345 
 
 10.1704 
 
 993 
 
 996004 
 
 99401 1992 
 
 31.5911 
 
 99933 
 
 1053 
 
 1108309 
 
 1167575877 
 
 324500 
 
 10.1736 
 
 999 
 
 993001 
 
 997002999 
 
 31.6070 
 
 9.9%; 
 
 1054 
 
 1110916 
 
 1170905464 
 
 32.4654 
 
 10.1769 
 
 1000 
 
 1000000 
 
 100000000C 
 
 31.6223 
 
 10.0000 
 
 1055 
 
 1113025 
 
 1174241375 
 
 32.4803 
 
 10 1801 
 
 1001 
 
 1002001 
 
 1003003001 
 
 31.6336 
 
 10.0033 
 
 1056 
 
 1115136 
 
 1177583616 
 
 32.4%2 
 
 10.1833 
 
 1002 
 
 1004004 
 
 1006012003 
 
 31.6544 
 
 10.006/ 
 
 1057 
 
 1117249 
 
 1180932193 
 
 32.5115 
 
 10.1865 
 
 1003 
 
 1006009 
 
 1009027027 
 
 31.6702 
 
 100100 
 
 1053 
 
 1119364 
 
 1184287112 
 
 32.5269 
 
 10.1897 
 
 1004 
 
 1008016 
 
 1012048064 
 
 31.636C 
 
 10.0133 
 
 1059 
 
 1121481 
 
 1 187648379 
 
 32.5423 
 
 10.1929 
 
 1005 
 
 1010025 
 
 1015075125 
 
 31.7017 
 
 100166 
 
 1060 
 
 1123600 
 
 1191016000 
 
 32.5576 
 
 10.1%1 
 
 1006 
 
 1012036 
 
 1018108216 
 
 31.7175 
 
 10.0200 
 
 1061 
 
 1125721 
 
 1194389981 
 
 32.5730 
 
 101993 
 
 1007 
 
 1014049 
 
 1021147343 
 
 31.7333 
 
 10.0233 
 
 1062 
 
 1127844 
 
 1 197770328 
 
 32.5883 
 
 10.2025 
 
 1008 
 
 1016064 
 
 1024192512 
 
 31 7490 
 
 100266 
 
 1063 
 
 1129%9 
 
 1201157047 
 
 32.6036 
 
 10.2057 
 
 1009 
 
 1018031 
 
 1027243729 
 
 31.7648 
 
 10.0299 
 
 1064 
 
 11320% 
 
 1204550144 
 
 32.6190 
 
 10.2039 
 
 1010 
 
 1020100 
 
 1030301000 
 
 31.7805 
 
 10.0332 
 
 1065 
 
 1134225 
 
 120794%25 
 
 32.6343 
 
 10.2121 
 
 1011 
 
 1022121 
 
 1033364331 
 
 31.7%2 
 
 10.0365 
 
 1066 
 
 1136356 
 
 12113554% 
 
 326497 
 
 10.2153 
 
 1012 
 
 1024144 
 
 1036433728 
 
 31.8119 
 
 10.0398 
 
 1067 
 
 1138489 
 
 1214767763 
 
 32.6650 
 
 10.2185 
 
 1013 
 
 1026169 
 
 1039509197 
 
 31.8277 
 
 100431 
 
 1063 
 
 1 140624 
 
 1218186432 
 
 32.6803 
 
 10.2217 
 
 1014 
 
 10281% 
 
 1042590744 
 
 31.8434 
 
 10.0465 
 
 1069 
 
 1 142761 
 
 1221611509 
 
 32.6956 
 
 10.2249 
 
 1015 
 
 1030225 
 
 1045678375 
 
 31.8591 
 
 100493 
 
 1070 
 
 1144900 
 
 1225043000 
 
 32.7109 
 
 10.2281 
 
 1016 
 
 1032256 
 
 10487720% 
 
 31.8743 
 
 10.0531 
 
 1071 
 
 1 147041 
 
 1228480911 
 
 32.7261 
 
 10.2313 
 
 1017 
 
 1034239 
 
 1051871913 
 
 31.8904 
 
 10.0563 
 
 1072 
 
 1149184 
 
 1231925248 
 
 32.7414 
 
 10.2345 
 
 1013 
 
 1036324 
 
 1054977832 
 
 31.9061 
 
 10.05% 
 
 1073 
 
 1151329 
 
 1235376017 
 
 32.7567 
 
 10.2376 
 
 1019 
 
 1033361 
 
 1053089859 
 
 31.9218 
 
 10.0629 
 
 1074 
 
 1153476 
 
 1238833224 
 
 32.7719 
 
 10.2403 
 
 1020 
 
 1040400 
 
 1061208000 
 
 31.9374 
 
 100662 
 
 107 
 
 1155625 
 
 1242296875 
 
 32.7872 
 
 10.2440 
 
 1021 
 
 1042441 
 
 1064332261 
 
 31.9531 
 
 10.0695 
 
 107o 
 
 1157776 
 
 1245766976 
 
 32.8024 
 
 10.2472 
 
 1022 
 
 1044434 
 
 1067462648 
 
 31.9687 
 
 10.0723 
 
 1077 
 
 1159929 
 
 1249243533 
 
 32.8177 
 
 10 2503 
 
 1023 
 
 1046529 
 
 1070599167 
 
 31.9844 
 
 10.0761 
 
 1078 
 
 1162084 
 
 125272655232.8329 
 
 10.2535 
 
 1024 
 
 1043576 
 
 1073741824 
 
 32.0000 
 
 10.0794 
 
 1079 
 
 1 164241 
 
 1256216039 
 
 32.8481 
 
 10.2567 
 
 1025 
 
 1050525 
 
 1076890625 
 
 32.0156 
 
 10.0326 
 
 1030 
 
 1166400 
 
 1259712000 
 
 32.8634 
 
 10.2599 
 
 1026 
 
 1052676 
 
 1030045576 
 
 32.0312 
 
 100359 
 
 1031 
 
 1 163561 
 
 1263214441 
 
 32.8786 
 
 10.2630 
 
 1027 
 
 1054729 
 
 1033206683 
 
 32.0468 
 
 10.0892 
 
 1032 
 
 1170724 
 
 1266723368 
 
 32.8933 
 
 10.2662 
 
 1028 
 
 1056734 
 
 1036373952 
 
 320624 
 
 10.0925 
 
 1033 
 
 1172389 
 
 1270238787 
 
 32.9090 
 
 10.2693 
 
 1029 
 
 1053341 
 
 1089547389 
 
 32.0780 
 
 10.0957 
 
 1034 
 
 1175056 
 
 1273760704 
 
 32.9242 
 
 10.2725 
 
 1030 
 
 1060900 
 
 1092727000 
 
 320936 
 
 10.099fi 
 
 1035 
 
 1177225 
 
 1277289125 
 
 32.9393 
 
 10 2757 
 
 1031 
 
 1062961 
 
 1095912791 
 
 32 1092 10 1023 
 
 1036 
 
 1179396 
 
 1280824056 
 
 32.9545 
 
 10.2783 
 
 1032 
 
 1065024 
 
 1099104768 
 
 32.1243 10.1055 
 
 1087 
 
 1181569 
 
 1284365503 
 
 32%97 
 
 10.2820 
 
 1033 
 
 1067089 
 
 1 102302937 
 
 32.1403 10.1088 
 
 1038 
 
 1183744 
 
 1287913472 
 
 32.9843 
 
 10.2851 
 
 1034 
 
 1069156 
 
 1 105507304 
 
 32.1559'10.1121 
 
 1089 
 
 1185921 
 
 1291467%9 
 
 330000 
 
 10.2883 
 
240 MC ANDREW'S FLOATING SCHOOL 
 
 CIRCUMFERENCES AND AREAS OF CIRCLES. 
 
 Diam. 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 1/64 
 
 . 04909 
 
 .00019 
 
 23/8 
 
 7.4613 
 
 4.4301 
 
 61/8 
 
 19.242 
 
 29 465 
 
 V32 
 
 .09818 
 
 .00077 
 
 7/16 
 
 7.6576 
 
 4.6664 
 
 V4 
 
 19.635 
 
 ZV . *fO J 
 
 30 680 
 
 3/64 
 
 .14726 
 
 .00173 
 
 V2 
 
 7.8540 
 
 4.9087 
 
 3/8 
 
 20.028 
 
 31 919 
 
 Vl6 
 
 .19635 
 
 .00307 
 
 9/16 
 
 8.0503 
 
 5.1572 
 
 1/2 
 
 20.420 
 
 33 1 83 
 
 3/32 
 
 .29452 
 
 . 00690 
 
 5/8 
 
 8.2467 
 
 5.4119 
 
 5/8 
 
 20.813 
 
 34 472 
 
 1/8 
 
 .39270 
 
 .01227 
 
 
 8.4430 
 
 5.6727 
 
 3/4 
 
 21.206 
 
 35 785 
 
 5/32 
 
 . 49087 
 
 .01917 
 
 a/? 
 
 8.6394 
 
 5.9396 
 
 7/8 
 
 21.598 
 
 37! 122 
 
 3/16 
 
 . 58905 
 
 .02761 
 
 13/16 
 
 8.8357 
 
 6.2126 
 
 7. 
 
 21.991 
 
 38 485 
 
 7/32 
 
 .68722 
 
 .03758 
 
 7/8 
 
 9.0321 
 
 6.4918 
 
 Vs 
 
 22.384 
 
 39^871 
 
 
 
 
 15/16 
 
 9.2284 
 
 6.7771 
 
 
 22.776 
 
 41 282 
 
 1/4 
 
 .78540 
 
 . 04909 
 
 
 
 
 3/8 
 
 23 . 1 69 
 
 42 '. 1 1 8 
 
 9/32 
 
 .88357 
 
 .06213 
 
 3. 
 
 9.4248 
 
 7 . 0686 
 
 !/> 
 
 23.562 
 
 44 ] 79 
 
 5/16 
 
 .98175 
 
 .07670 
 
 Vie 
 
 9.6211 
 
 7.3662 
 
 58 
 
 23.955 
 
 45 664 
 
 H/32 
 
 .0799 
 
 .09281 
 
 Vs 
 
 9.8175 
 
 7 . 6699 
 
 3/4 
 
 24.347 
 
 47! 173 
 
 3/8 
 
 .1781 
 
 .11045 
 
 3 /16 
 
 10 014 
 
 7.9798 
 
 7/8 
 
 24 740 
 
 48 '. 707 
 
 13/32 
 
 .2763 
 
 .12962 
 
 V4 
 
 10.210 
 
 8.2958 
 
 8. 
 
 25.133 
 
 50.265 
 
 7/16 
 
 .3744 
 
 .15033 
 
 5/16 
 
 10.407 
 
 8.6179 
 
 1/8 
 
 25.525 
 
 51 849 
 
 15/32 
 
 .4726 
 
 .17257 
 
 3/8 
 
 10.603 
 
 8 . 9462 
 
 
 25.918 
 
 53 455 
 
 
 
 
 7/16 
 
 10.799 
 
 9.2806 
 
 3 /8 
 
 26.311 
 
 55 088 
 
 V2 
 17/32 
 
 .5708 
 .6690 
 
 .19635 
 .22166 
 
 V2 
 9/16 
 
 10.996 
 11.192 
 
 9 . 62 1 1 
 9.9678 
 
 V2 
 5/8 
 
 26.704 
 27.096 
 
 56. '745 
 58 426 
 
 9/16 
 
 .7671 
 
 .24850 
 
 5/8 
 
 1 1 . 388 
 
 10.321 
 
 3/4 
 
 27.489 
 
 60. 132 
 
 19/32 
 
 .8653 
 
 , 27688 
 
 n/ie 
 
 11.585 
 
 10.680 
 
 7g 
 
 27 882 
 
 61 ^862 
 
 5/8 
 
 .9635 
 
 . 30680 
 
 3/4 
 
 11.781 
 
 11.045 
 
 9. 
 
 28.274 
 
 63 617 
 
 21/32 
 
 2.0617 
 
 .33824 
 
 13/16 
 
 11.977 
 
 11.416 
 
 1/8 
 
 28.667 
 
 65 397 
 
 11/16 
 
 2.1598 
 
 .37122 
 
 7/8 
 
 12.174 
 
 1 1 . 793 
 
 1/4 
 
 29.060 
 
 67 201 
 
 23/32 
 
 2.2580 
 
 .40574 
 
 15/16 
 
 12.370 
 
 12.177 
 
 3/8 
 
 29.452 
 
 69.029 
 
 
 
 
 4. 
 
 12.566 
 
 12.566 
 
 1/2 
 
 29 845 
 
 70.882 
 
 3/4 
 
 2.3562 
 
 .44179 
 
 Vl6 
 
 12.763 
 
 1 2 . 962 
 
 5/8 
 
 30.238 
 
 72.760 
 
 23/32 
 
 2.4544 
 
 .47937 
 
 1/8 
 
 12.959 
 
 13.364 
 
 3/4 
 
 30.631 
 
 74 662 
 
 13/16 
 
 2.5525 
 
 .51849 
 
 3/16 
 
 13.155 
 
 13.772 
 
 7/8 
 
 31 023 
 
 76.589 
 
 27/32 
 
 2.6507 
 
 .55914 
 
 1/4 
 
 13.352 
 
 14.186 
 
 10. 
 
 31.416 
 
 78^540 
 
 7/8 
 
 2.7489 
 
 .60132 
 
 5/16 
 
 13.548 
 
 14.607 
 
 
 31 809 
 
 80 516 
 
 29/32 
 
 2.8471 
 
 . 64504 
 
 3/8 
 
 13.744 
 
 15.033 
 
 1/4 
 
 32.201 
 
 82.516 
 
 15/ig 
 
 2.9452 
 
 . 69029 
 
 7/16 
 
 13.941 
 
 15.466 
 
 3/8 
 
 32.594 
 
 84 541 
 
 31/32 
 
 3.0434 
 
 .73708 
 
 1/2 
 
 14.137 
 
 1 5 . 904 
 
 1/2 
 
 32.987 
 
 86.590 
 
 
 
 
 9/16 
 
 14.334 
 
 16.349 
 
 5 /8 
 
 33.379 
 
 88.664 
 
 1. 
 
 3.1416 
 
 .7854 
 
 5/8 
 
 14.530 
 
 1 6 . 800 
 
 3/4 
 
 33.772 
 
 90.763 
 
 Vl6 
 
 3.3379 
 
 .8866 
 
 
 14.726 
 
 17.257 
 
 7/8 
 
 34.165 
 
 92 . 886 
 
 1/8 
 
 3.5343 
 
 .9940 
 
 9/4 
 
 14.923 
 
 17.721 
 
 11. 
 
 34.558 
 
 95.033 
 
 3/16 
 
 3.7306 
 
 .1075 
 
 13/16 
 
 15.119 
 
 18. 190 
 
 Vs 
 
 34.950 
 
 97.205 
 
 V4 
 
 3.9270 
 
 .2272 
 
 7/8 
 
 15.315 
 
 18.665 
 
 1/4 
 
 35.343 
 
 99.402 
 
 5/16 
 
 4.1233 
 
 .3530 
 
 13/16 
 
 15.512 
 
 19. 147 
 
 3/8 
 
 35.736 
 
 101.62 
 
 3/8 
 
 4.3197 
 
 .4849 
 
 5. 
 
 1 5 . 708 
 
 19.635 
 
 
 36. 128 
 
 103.87 
 
 7/16 
 
 4.5160 
 
 .6230 
 
 Vl6 
 
 1 5 . 904 
 
 20. 129 
 
 5/8 
 
 36.521 
 
 106.14 
 
 1/2 
 
 4.7124 
 
 .7671 
 
 Vs 
 
 16. 101 
 
 20.629 
 
 3/4 
 
 36.914 
 
 108.43 
 
 9/16 
 
 4.9087 
 
 .9175 
 
 3/16 
 
 16.297 
 
 21.135 
 
 7/8 
 
 37.306 
 
 110.75 
 
 5/8 
 
 5.1051 
 
 2.0739 
 
 1/4 
 
 16.493 
 
 2 1 . 648 
 
 12. 
 
 37.699 
 
 113.10 
 
 H/16 
 
 5.3014 
 
 2.2365 
 
 5/16 
 
 16.690 
 
 22.166 
 
 1/8 
 
 38.092 
 
 115.47 
 
 ^3/4 
 
 5.4978 
 
 2.4053 
 
 3/8 
 
 16.886 
 
 22.691 
 
 
 38.485 
 
 117.86 
 
 13, 16 
 
 5.6941 
 
 2.5802 
 
 7/16 
 
 17.082 
 
 23.221 
 
 3/8 
 
 38.877 
 
 120.28 
 
 7 /8 
 
 5 . 8905 
 
 2.7612 
 
 1/2 
 
 17.279 
 
 23.758 
 
 1/2 
 
 39.270 
 
 122.72 
 
 15 /16 
 
 6.0868 
 
 2.9483 
 
 9/16 
 
 17.475 
 
 24.301 
 
 5/8 
 
 39.663 
 
 125.19 
 
 
 
 
 5/8 
 
 17.671 
 
 24.850 
 
 3/4 
 
 40.055 
 
 127.68 
 
 2. 
 
 6.2832 
 
 3.1416 
 
 n /16 
 
 1 7 . 868 
 
 25.406 
 
 7/8 
 
 40.448 
 
 130.19 
 
 1/16 
 
 6.4795 
 
 3.3410 
 
 3/4 
 
 18.064 
 
 25.967 
 
 13. 
 
 40.841 
 
 132.73 
 
 1/8 
 
 6.6759 
 
 3.5466 
 
 13/16 
 
 18.261 
 
 26.535 
 
 1/8 
 
 41.233 
 
 135 30 
 
 3/16 
 
 6.8722 
 
 3.7583 
 
 7/8 
 
 18.457 
 
 27.109 
 
 1/4 
 
 41.626 
 
 137.89 
 
 V4 
 
 7 . 0686 
 
 3.9761 
 
 15/16 
 
 18.653 
 
 27 . 688 
 
 3/8 
 
 42.019 
 
 140.50 
 
 5/16 
 
 7.2649 
 
 4.2000 
 
 
 18.850 
 
 28.274 
 
 1/2 
 
 42.412 
 
 143. 14 
 
 Republished by permission of Messrs. John Wiley & Sons, Inc. 
 from Kent's Mechanical Engineers Pocket- Book. 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 241 
 
 Diara. 
 
 Circura. 
 
 Area. 
 
 Diam. 
 
 Circum. 
 
 Area. 
 
 Diam. 
 
 Circum. 
 
 Area. 
 
 135/8 
 
 42.804 
 
 145.80 
 
 217/8 
 
 68.722 
 
 375.83 
 
 30 1/8 
 
 94.640 
 
 712 76 
 
 3/ A 
 
 43. 197 
 
 148.49 
 
 22. 
 
 69.115 
 
 380. 13 
 
 V4 
 
 95.033 
 
 7 1 8 69 
 
 7 /8 
 
 43.590 
 
 1 5 1 . 20 
 
 17 8 
 
 69.508 
 
 384.46 
 
 3/8 
 
 95.426 
 
 724 64 
 
 14. 
 
 43.982 
 
 153.94 
 
 1/4 
 
 69.900 
 
 388.82 
 
 1/2 
 
 95.819 
 
 730 '62 
 
 1/8 
 
 44.375 
 
 156.70 
 
 3/8 
 
 70.293 
 
 393.20 
 
 5/8 
 
 96.211 
 
 736 62 
 
 i// 
 
 44.768 
 
 159.48 
 
 V* 
 
 70.686 
 
 397.61 
 
 3/4 
 
 96.604 
 
 742 64 
 
 3/8 
 
 45.160 
 
 162.30 
 
 5 /8 
 
 71.079 
 
 402.04 
 
 7/8 
 
 96.997 
 
 748.69 
 
 1/2 
 
 45.553 
 
 165.13 
 
 3/4 
 
 71.471 
 
 406.49 
 
 31. 
 
 97.389 
 
 754 77 
 
 5/8 
 
 45.946 
 
 1 67 . 99 
 
 7/8 
 
 7 1 . 864 
 
 410.97 
 
 1/8 
 
 97.782 
 
 760 87 
 
 3/4 
 
 46.338 
 
 170.87 
 
 23. 
 
 72.257 
 
 415.48 
 
 1/4 
 
 98.175 
 
 766 99 
 
 7/8 
 
 46.731 
 
 173.78 
 
 V8 
 
 72.649 
 
 420.00 
 
 3/8 
 
 98.567 
 
 773. 14 
 
 15. 
 
 47.124 
 
 176.7! 
 
 1/4 
 
 73.042 
 
 424.56 
 
 V2 
 
 98.960 
 
 779 31 
 
 1/8 
 
 47.517 
 
 179.67 
 
 3/8 
 
 73.435 
 
 429.13 
 
 5/8 
 
 99.353 
 
 785 51 
 
 1/4 
 
 47.909 
 
 182.65 
 
 1/2 
 
 73.827 
 
 433.74 
 
 3/4 
 
 99.746 
 
 791 73 
 
 3/8 
 
 48.302 
 
 185.66 
 
 5/8 
 
 74.220 
 
 438.36 
 
 7/8 
 
 100.138 
 
 797 98 
 
 Va 
 
 48.695 
 
 188.69 
 
 3/4 
 
 74.613 
 
 443.01 
 
 32. 
 
 100.531 
 
 804.25 
 
 5/3 
 
 49.037 
 
 191.75 
 
 7/8 
 
 75.006 
 
 447.69 
 
 V8 
 
 100.924 
 
 810.54 
 
 3/4 
 
 49.480 
 
 194.83 
 
 24. 
 
 75.398 
 
 452.39 
 
 1/4 
 
 101.316 
 
 816.86 
 
 7/8 
 
 49.873 
 
 197.93 
 
 V8 
 
 75.791 
 
 457.11 
 
 3/8 
 
 101.709 
 
 823.21 
 
 16. 
 
 50.265 
 
 201.06 
 
 1/4 
 
 76. 184 
 
 461.86 
 
 1/2 
 
 102.102 
 
 829.58 
 
 1/8 
 
 50.658 
 
 204.22 
 
 3/8 
 
 76.576 
 
 466.64 
 
 5/8 
 
 1 02 . 494 
 
 835.97 
 
 V4 
 
 51.051 
 
 207.39 
 
 1/2 
 
 76.969 
 
 47 1 . 44 
 
 3/4 
 
 102.887 
 
 842.39 
 
 3/8 
 
 51.414 
 
 210.60 
 
 5/8 
 
 77.362 
 
 476.26 
 
 7/8 
 
 103.280 
 
 848.83 
 
 1/2 
 
 51.836 
 
 213.82 
 
 3/4 
 
 77.754 
 
 431.11 
 
 33. 
 
 103.673 
 
 855.30 
 
 5/8 
 
 52.229 
 
 217.08 
 
 7/8 
 
 78.147 
 
 485.98 
 
 Vg 
 
 104.065 
 
 861.79 
 
 3/4 
 
 52.622 
 
 220.35 
 
 25. 
 
 78.540 
 
 490.87 
 
 1/4 
 
 104.458 
 
 868.31 
 
 7/8 
 
 53.014 
 
 223.65 
 
 1/8 
 
 78.933 
 
 495.79 
 
 3/8 
 
 104.851 
 
 874.85 
 
 17. 
 
 53.407 
 
 226.98 
 
 1/4 
 
 79.325 
 
 500.74 
 
 1/2 
 
 105.243 
 
 881.41 
 
 Vs 
 
 53.800 
 
 230.33 
 
 3/8 
 
 79.718 
 
 505.71 
 
 5/8 
 
 105.636 
 
 888.00 
 
 1/4 
 
 54. 192 
 
 233.71 
 
 1/9 
 
 80.111 
 
 510.71 
 
 3/4 
 
 106.029 
 
 894 . 62 
 
 3/8 
 
 54.585 
 
 237.10 
 
 5/8 
 
 80.503 
 
 515.72 
 
 7/8 
 
 106.421 
 
 901.26 
 
 1/2 
 
 54.978 
 
 240.53 
 
 3/ 4 
 
 80.896 
 
 520.77 
 
 34. 
 
 106.814 
 
 907 . 92 
 
 5/8 
 
 55.371 
 
 243.98 
 
 7/8 
 
 81.289 
 
 525.84 
 
 1/8 
 
 107.207 
 
 914.61 
 
 3/4 
 
 55.763 
 
 247.45 
 
 26. 
 
 81.681 
 
 530.93 
 
 1/4 
 
 107.600 
 
 921.32 
 
 7/8 
 
 56.156 
 
 250.95 
 
 1/8 
 
 82.074 
 
 536.05 
 
 3/8 
 
 107.992 
 
 928.06 
 
 18. 
 
 56.549 
 
 254.47 
 
 1/4 
 
 82.467 
 
 541.19 
 
 1/2 
 
 108.385 
 
 934.82 
 
 1/8 
 
 56 941 
 
 258 02 
 
 3/8 
 
 82.860 
 
 546.35 
 
 5/8 
 
 108.778 
 
 941.61 
 
 1/4 
 
 57.334 
 
 261.59 
 
 1/9 
 
 83.252 
 
 551.55 
 
 3/4 
 
 109.170 
 
 948.42 
 
 3 /8 
 
 57.727 
 
 265.18 
 
 5/8 
 
 83.645 
 
 556.76 
 
 7/8 
 
 109.563 
 
 955.25 
 
 v" 
 
 58.119 
 
 268.80 
 
 3/4 
 
 84.038 
 
 562.00 
 
 35. 
 
 109.956 
 
 962.11 
 
 5/8 
 
 58.512 
 
 272.45 
 
 7/8 
 
 84.430 
 
 567.27 
 
 1/8 
 
 110.348 
 
 969 . 00 
 
 3/4 
 
 58.905 
 
 276.12 
 
 27. 
 
 84.823 
 
 572.56 
 
 V4 
 
 110.741 
 
 975.91 
 
 7/8 
 
 59.298 
 
 279.81 
 
 Vs 
 
 85.216 
 
 577.87 
 
 3/8 
 
 111.134 
 
 982 . 84 
 
 19. 
 
 59.690 
 
 283.53 
 
 1/4 
 
 85.608 
 
 583.21 
 
 1/2 
 
 111.527 
 
 939.80 
 
 1/8 
 
 60.083 
 
 287.27 
 
 3/8 
 
 86.001 
 
 588.57 
 
 5/8 
 
 111.919 
 
 996.78 
 
 1/4 
 
 60 476 
 
 291.04 
 
 1/9 
 
 86.394 
 
 593.96 
 
 3/4 
 
 112.312 
 
 1003.8 
 
 S/g 
 
 60.868 
 
 294.83 
 
 5 /8 
 
 86.786 
 
 599.37 
 
 7,8 
 
 112.705 
 
 1010.8 
 
 1/9 
 
 61.261 
 
 298.65 
 
 3/4 
 
 87.179 
 
 604.81 
 
 36. 
 
 113.097 
 
 1017.9 
 
 5/g 
 
 61 654 
 
 302.49 
 
 7/8 
 
 87.572 
 
 610.27 
 
 Vs 
 
 1 1 3 . 490 
 
 1025.0 
 
 3/4 
 
 62 046 
 
 3C5 35 
 
 28. 
 
 87.965 
 
 615.75 
 
 1/4 
 
 113.883 
 
 1032.1 
 
 7/8 
 
 62.439 
 
 310.24 
 
 1/8 
 
 88.357 
 
 621.26 
 
 3/8 
 
 114.275 
 
 1039.2 
 
 20. 
 
 62 832 
 
 314.16 
 
 1/4 
 
 88.750 
 
 626.80 
 
 1/2 
 
 114.668 
 
 1046.3 
 
 1/8 
 
 63.225 
 
 318.10 
 
 Jj/8 
 
 89.143 
 
 632.36 
 
 5/8 
 
 115.061 
 
 1053.5 
 
 1/4 
 
 63 617 
 
 322 06 
 
 1/9 
 
 89.535 
 
 637.94 
 
 3/ 4 
 
 115.454 
 
 1060.7 
 
 3/8 
 
 1/9 
 
 64!010 
 64 403 
 
 326.05 
 330 06 
 
 5/8 
 
 3/4 
 
 89.928 
 90.321 
 
 643.55 
 649.18 
 
 7/8 
 
 37. 
 
 115.846 
 116.239 
 
 1068.0 
 1075.2 
 
 5 Q 
 
 64.795 
 
 334 10 
 
 7/8 
 
 90.713 
 
 654.84 
 
 1/8 
 
 116.632 
 
 1032.5 
 
 3/5 
 
 65 188 
 
 338.16 
 
 29. 
 
 91.106 
 
 660.52 
 
 1/4 
 
 117.024 
 
 1089.8 
 
 7,8 
 
 65 581 
 
 342 25 
 
 1/8 
 
 91.499 
 
 666.23 
 
 3/8 
 
 117.417 
 
 1097.1 
 
 21. 
 
 65.973 
 
 346.36 
 
 1/4 
 
 91.892 
 
 671.96 
 
 1/2 
 
 117.810 
 
 1104.5 
 
 Vg 
 
 1/4 
 3 'g 
 
 66.366 
 66.759 
 6> 1 52 
 
 350.50 
 354.66 
 358 84 
 
 8 
 
 5/8 
 
 92 . 284 
 92.677 
 93.070 
 
 677.71 
 683 . 49 
 689.30 
 
 5/8 
 3/4 
 7/8 
 
 1 18.202 
 118.596 
 118.988 
 
 \\\9'.2 
 1126.7 
 
 1/2 
 -8 
 3 4 
 
 67! 544 
 67.937 
 63.330 
 
 363.05 
 367.28 
 371.54 
 
 3/4 
 7/8 
 30. 
 
 93 . 462 
 93.855 
 94.248 
 
 695.13 
 700.98 
 706 . 86 
 
 38. 
 
 V8 
 
 1/4 
 
 119.381 
 119.773 
 120.166 
 
 1 134. 1 
 1141.6 
 1149.1 
 
242 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 Dlam 
 
 Circum. 
 
 Area. 
 
 Diara 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 383/8 
 
 120.559 
 
 1156.6 
 
 465/8 
 
 146.477 
 
 1707.4 
 
 547/j, 
 
 172.395 
 
 2365.0 
 
 1/2 
 
 120.951 
 
 1164.2 
 
 3/4 
 
 146.869 
 
 1716.5 
 
 55. 
 
 172.788 
 
 2375.8 
 
 5/8 
 
 121.344 
 
 1171.7 
 
 7/8 
 
 147.262 
 
 1725.7 
 
 1/8 
 
 173. 180 
 
 2386.6 
 
 3/4 
 
 121.737 
 
 1179.3 
 
 47. 
 
 147.655 
 
 1734.9 
 
 1/4 
 
 173.573 
 
 2397.5 
 
 7/8 
 
 122. 129 
 
 1186.9 
 
 i/s 
 
 148.048 
 
 1744.2 
 
 3/8 
 
 1 73 . 966 
 
 2408.3 
 
 39. 
 
 122.522 
 
 1194.6 
 
 1/4 
 
 148.440 
 
 1753.5 
 
 1/2 
 
 174.358 
 
 2419.2 
 
 1/8 
 
 122.915 
 
 1202.3 
 
 3/8 
 
 148.833 
 
 1762.7 
 
 5/8 
 
 174.751 
 
 2430. 1 
 
 1/4 
 
 123.308 
 
 1210.0 
 
 Va 
 
 149.226 
 
 1772.1 
 
 3/4 
 
 175. 144 
 
 2441. 1 
 
 3/8 
 
 123.700 
 
 1217.7 
 
 5/8 
 
 149.618 
 
 1781.4 
 
 7/8 
 
 175.536 
 
 2452.0 
 
 1/2 
 
 124.093 
 
 1225.4 
 
 3/4 
 
 150.011 
 
 1790.8 
 
 56. 
 
 175.929 
 
 2463.0 
 
 5/8 
 
 124.486 
 
 1233.2 
 
 7/8 
 
 150.404 
 
 1800.1 
 
 1/8 
 
 176.322 
 
 2474.0 
 
 3/4 
 
 124.878 
 
 1241.0 
 
 48. 
 
 150.796 
 
 1809.6 
 
 1/4 
 
 176.715 
 
 2485.0 
 
 7/a 
 
 125.271 
 
 1248.8 
 
 V8 
 
 151.189 
 
 1819.0 
 
 3/8 
 
 177. 107 
 
 2496 1 
 
 40. 
 
 125.664 
 
 1256.6 
 
 1/4 
 
 151.582 
 
 1828.5 
 
 Va 
 
 177.500 
 
 2507.2 
 
 1/8 
 
 126.056 
 
 1264.5 
 
 3/8 
 
 151.975 
 
 1837.9 
 
 5 /8 
 
 177.893 
 
 2518.3 
 
 V4 
 
 126.449 
 
 1272.4 
 
 1/2 
 
 152.367 
 
 1847.5 
 
 3/4 
 
 178.285 
 
 2529.4 
 
 3/8 
 
 126.842 
 
 1280.3 
 
 5/8 
 
 152.760 
 
 1857.0 
 
 7/8 
 
 178.678 
 
 2540.6 
 
 1/9 
 
 127.235 
 
 1288.2 
 
 3/4 
 
 153.153 
 
 1866.5 
 
 57. 
 
 179.071 
 
 2551.8 
 
 5/8 
 
 127.627 
 
 1296.2 
 
 7/8 
 
 153.545 
 
 1876.1 
 
 1/8 
 
 179.463 
 
 2563.0 
 
 3/4 
 
 128.020 
 
 1304.2 
 
 49. 
 
 153.938 
 
 1885.7 
 
 1/4 
 
 179.856 
 
 2574.2 
 
 7/8 
 
 128.413 
 
 1312.2 
 
 1/8 
 
 154.331 
 
 1895.4 
 
 3/8 
 
 180.249 
 
 2585.4 
 
 41. 
 
 128.805 
 
 1320.3 
 
 1/4 
 
 154.723 
 
 1905.0 
 
 Va 
 
 180.642 
 
 2596.7 
 
 1/8 
 
 129.198 
 
 1328.3 
 
 3/8 
 
 155.116 
 
 1914.7 
 
 5/8 
 
 181.034 
 
 2608.0 
 
 V4 
 
 129.591 
 
 1336.4 
 
 1/2 
 
 155.509 
 
 1924.4 
 
 3/4 
 
 181.427 
 
 2619.4 
 
 3/8 
 
 129.983 
 
 1344.5 
 
 5 /8 
 
 155.902 
 
 1934.2 
 
 7/8 
 
 181.820 
 
 2630.7 
 
 1/2 
 
 130.376 
 
 1352.7 
 
 3/4 
 
 156.294 
 
 1943.9 
 
 58. 
 
 182.212 
 
 2642. 1 
 
 5/8 
 
 130.769 
 
 1360.8 
 
 7/8 
 
 156.637 
 
 1953.7 
 
 1/8 
 
 182.605 
 
 2653.5 
 
 3/4 
 
 131.161 
 
 1369.0 
 
 50. 
 
 157.080 
 
 1963.5 
 
 V4 
 
 182.998 
 
 2664.9 
 
 7/8 
 
 131.554 
 
 1377.2 
 
 1/8 
 
 157.472 
 
 1973.3 
 
 3/8 
 
 183.390 
 
 2676.4 
 
 42. 
 
 131.947 
 
 1385.4 
 
 1/4 
 
 157.865 
 
 1983.2 
 
 Va 
 
 183.783 
 
 2687.8 
 
 1/8 
 
 132.340 
 
 1393.7 
 
 M 
 
 158.258 
 
 1 993 . 1 
 
 5/8 
 
 184.176 
 
 2699.3 
 
 1/4 
 
 132.732 
 
 1402.0 
 
 Va 
 
 158.650 
 
 2003.0 
 
 3/4 
 
 184.569 
 
 2710.9 
 
 3/8 
 
 133.125 
 
 1410.3 
 
 5/8 
 
 159.043 
 
 2012.9 
 
 7/8 
 
 184.961 
 
 2722.4 
 
 1/9 
 
 133.518 
 
 1418.6 
 
 3/4 
 
 159.436 
 
 2022.8 
 
 59. 
 
 185.354 
 
 2734.0 
 
 5/8 
 
 133.910 
 
 1427.0 
 
 7/8 
 
 159.829 
 
 2032.8 
 
 1/8 
 
 185.747 
 
 2745.6 
 
 3/4 
 
 134.303 
 
 1435.4 
 
 51. 
 
 160.221 
 
 2042.8 
 
 1/4 
 
 186.139 
 
 2757.2 
 
 7/8 
 
 134.696 
 
 1443.8 
 
 1/8 
 
 160.614 
 
 2052.8 
 
 3/8 
 
 186.532 
 
 2768.8 
 
 43. 
 
 135.088 
 
 1452.2 
 
 1/4 
 
 161.007 
 
 2062 . 9 
 
 1/2 
 
 186.925 
 
 2780.5 
 
 1/8 
 
 135.481 
 
 1460.7 
 
 3/8 
 
 161.399 
 
 2073.0 
 
 $ 
 
 187.317 
 
 2792.2 
 
 V4 
 
 135.874 
 
 1469.1 
 
 Va 
 
 161.792 
 
 2083 . 1 
 
 3/4 
 
 187.710 
 
 2803.9 
 
 3/8 
 
 136.267 
 
 1477.6 
 
 5/8 
 
 162.185 
 
 2093.2 
 
 7/8 
 
 188. 103 
 
 2815.7 
 
 1/2 
 
 136.659 
 
 1486.2 
 
 3/4 
 
 162.577 
 
 2103.3 
 
 60. 
 
 188.496 
 
 2827.4 
 
 5/8 
 
 137.052 
 
 1 494 . 7 
 
 7/8 
 
 162.970 
 
 2113.5 
 
 1/8 
 
 188.888 
 
 2839.2 
 
 3/4 
 
 137.445 
 
 1503.3 
 
 69. 
 
 163.363 
 
 2123.7 
 
 1/4 
 
 189.281 
 
 2851.0 
 
 7/8 
 
 137.837 
 
 1511.9 
 
 V8 
 
 163.756 
 
 2133.9 
 
 3/8 
 
 189.674 
 
 2862.9 
 
 44. 
 
 138.230 
 
 1520.5 
 
 1/4 
 
 164.148 
 
 2144.2 
 
 1/2 
 
 190.066 
 
 2874.8 
 
 1/8 
 
 138.623 
 
 1529.2 
 
 3/8 
 
 164.541 
 
 2154.5 
 
 5/8 
 
 190.459 
 
 2886.6 
 
 !/4 
 
 139.015 
 
 1537.9 
 
 1/2 
 
 164.934 
 
 2164.8 
 
 3/4 
 
 190.852 
 
 2898.6 
 
 3/8 
 
 139.408 
 
 1546.6 
 
 5/8 
 
 165.326 
 
 2175.1 
 
 7/8 
 
 191.244 
 
 2910.5 
 
 1/9 
 
 139.801 
 
 1555.3 
 
 3/4 
 
 165.719 
 
 2185.4 
 
 61. 
 
 191.637 
 
 2922.5 
 
 5/8 
 
 140.194 
 
 1564.0 
 
 7/8 
 
 166.112 
 
 2195.8 
 
 !/8 
 
 192.030 
 
 2934.5 
 
 3/4 
 
 140.586 
 
 1572.8 
 
 53. 
 
 166.504 
 
 2206.2 
 
 1/4 
 
 192.423 
 
 2946.5 
 
 7/8 
 
 140.979 
 
 1581.6 
 
 1/8 
 
 166.897 
 
 2216.6 
 
 3/8 
 
 192.815 
 
 2958.5 
 
 45. 
 
 141.372 
 
 1590.4 
 
 1/4 
 
 167.290 
 
 2227.0 
 
 1/2 
 
 193.208 
 
 2970.6 
 
 1/8 
 
 141.764 
 
 1599.3 
 
 3/8 
 
 167.683 
 
 2237.5 
 
 5 /8 
 
 193.601 
 
 2982 . 7 
 
 !/4 
 
 142.157 
 
 1608.2 
 
 1/2 
 
 168.075 
 
 2248.0 
 
 34 
 
 193.993 
 
 2994.8 
 
 3/8 
 
 142.550 
 
 1617.0 
 
 5/8 
 
 168.468 
 
 2258.5 
 
 7/8 
 
 194.386 
 
 3006.9 
 
 1/2 
 
 142 942 
 
 1626.0 
 
 3/4 
 
 168.861 
 
 2269. 1 
 
 62. 
 
 194.779 
 
 3019.1 
 
 5/8 
 
 143.335 
 
 1634.9 
 
 7/8 
 
 169.253 
 
 2279.6 
 
 1/8 
 
 195.171 
 
 3031.3 
 
 3/4 
 
 143.728 
 
 1643.9 
 
 54. 
 
 169.646 
 
 2290.2 
 
 1/4 
 
 195.564 
 
 3043.5 
 
 7/8 
 
 144 121 
 
 1652.9 
 
 l/ 8 
 
 170.039 
 
 23C0.8 
 
 3/8 
 
 195.957 
 
 3055.7 
 
 46. 
 
 144.513 
 
 1661.9 
 
 1/4 
 
 170.431 
 
 2311.5 
 
 Va 
 
 196.350 
 
 3068.0 
 
 1/8 
 
 144.906 
 
 1670.9 
 
 3/8 
 
 170.824 
 
 2322.1 
 
 5/8 
 
 196.742 
 
 3080.3 
 
 1/4 
 
 145.299 
 
 1680.0 
 
 V2 
 
 171.217 
 
 2332.8 
 
 3/4 
 
 197.135 
 
 3092.6 
 
 3/8 
 
 145.691 
 
 1689.5 
 
 5/8 
 
 1 7 1 . 609 
 
 2343.5 
 
 7/8 
 
 197.528 
 
 3104 9 
 
 1/2 
 
 146.084 
 
 1698,2 
 
 3/4 
 
 1 72 . 002 
 
 2354.3 
 
 63. 
 
 197.920 
 
 3117.2 
 
USEFUL TABLES FOR MARINE ENGINEERS 
 
 243 
 
 Diam. 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 63 Vs 
 
 198.313 
 
 3129.6 
 
 71 a/s 
 
 224. 23 i 
 
 4001. 1 
 
 795/a 
 
 250. 149 
 
 4979.5 
 
 1/4 
 
 198.706 
 
 3142.0 
 
 1/2 
 
 224.624 
 
 4015.2 
 
 3/4 
 
 250 542 
 
 4995 2 
 
 3/8 
 
 199.098 
 
 3154.5 
 
 5/8 
 
 225.017 
 
 4029.2 
 
 7/8 
 
 250.935 
 
 5010 9 
 
 V2 
 
 199.491 
 
 3166.9 
 
 3/4 
 
 225.409 
 
 4043.3 
 
 80. 
 
 251.327 
 
 5026 '5 
 
 5/8 
 
 199.884 
 
 3179.4 
 
 7/8 
 
 225.802 
 
 4057.4 
 
 1/8 
 
 251.720 
 
 5042 '3 
 
 3/4 
 
 200.277 
 
 3191.9 
 
 73. 
 
 226.195 
 
 407 1 . 5 
 
 1/4 
 
 252.113 
 
 5058 
 
 7 /8 
 
 200.669 
 
 3204.4 
 
 1/8 
 
 226.587 
 
 4085.7 
 
 3/8 
 
 252 506 
 
 5073 8 
 
 64. 
 
 201.062 
 
 3217.0 
 
 V4 
 
 226.980 
 
 4099.8 
 
 !/2 
 
 252.898 
 
 5089.6 
 
 i/s 
 
 201.455 
 
 3229.6 
 
 3/8 
 
 227.373 
 
 4114.0 
 
 5/8 
 
 253.291 
 
 5105 4 
 
 1/4 
 
 201.847 
 
 3242.2 
 
 1/2 
 
 227.765 
 
 4128.2 
 
 3 /4 
 
 253.684 
 
 5121 2 
 
 3/8 
 
 202.240 
 
 3254.8 
 
 5/8 
 
 223.158 
 
 4142.5 
 
 7/8 
 
 254.076 
 
 5137.1 
 
 Va 
 
 202.633 
 
 3267.5 
 
 3/4 
 
 228.551 
 
 4156.8 
 
 81. 
 
 254.469 
 
 5153.0 
 
 5/8 
 
 203.025 
 
 3280.1 
 
 7/8 
 
 228.944 
 
 4171.1 
 
 1/0 
 
 254.862 
 
 5168 9 
 
 3/4 
 
 203.418 
 
 3292.8 
 
 73. 
 
 229.336 
 
 4185.4 
 
 14 
 
 255.254 
 
 5184.9 
 
 7/8 
 
 203.811 
 
 3305.6 
 
 1/8 
 
 229.729 
 
 4199.7 
 
 3/8 
 
 255.647 
 
 5200.8 
 
 65. 
 
 204.204 
 
 3318.3 
 
 V4 
 
 230.122 
 
 4214.1 
 
 1/2 
 
 256.040 
 
 5216.8 
 
 1/8 
 
 204.596 
 
 3331.1 
 
 3/8 
 
 230.514 
 
 4228.5 
 
 5/8 
 
 256.433 
 
 5232.8 
 
 V4 
 
 204.989 
 
 3343.9 
 
 1/2 
 
 230.907 
 
 4242.9 
 
 3/4 
 
 256.825 
 
 5248.9 
 
 3/8 
 
 205.382 
 
 3356.7 
 
 5/8 
 
 231.303 
 
 4257.4 
 
 7/8 
 
 257.218 
 
 5264.9 
 
 1/2 
 
 205.774 
 
 3369.6 
 
 3/4 
 
 231.692 
 
 4271.8 
 
 82. 
 
 257.611 
 
 5281.0 
 
 5/8 
 
 206.167 
 
 3382.4 
 
 7/8 
 
 232.085 
 
 4286.3 
 
 1/8 
 
 258.003 
 
 5297.1 
 
 3/4 
 
 206.560 
 
 3395.3 
 
 74. 
 
 232.478 
 
 4300.8 
 
 1/4 
 
 258.396 
 
 5313.3 
 
 7 /8 
 
 206.952 
 
 3408.2 
 
 1/8 
 
 232.871 
 
 4315.4 
 
 3/8 
 
 258.789 
 
 5329.4 
 
 66. 
 
 207.345 
 
 3421.2 
 
 1/4 
 
 233.263 
 
 4329.9 
 
 1/2 
 
 259.181 
 
 5345.6 
 
 Vi 
 
 207.738 
 
 3434.2 
 
 3/8 
 
 233.656 
 
 4344.5 
 
 5/8 
 
 259.574 
 
 5361.8 
 
 V* 
 
 208.131 
 
 3447.2 
 
 1/2 
 
 234.049 
 
 4359.2 
 
 3/4 
 
 259.967 
 
 5378.1 
 
 3/8 
 
 208.523 
 
 3460.2 
 
 5/8 
 
 234.441 
 
 4373.8 
 
 7/8 
 
 260.359 
 
 5394.3 
 
 Va 
 
 208.916 
 
 3473.2 
 
 3/4 
 
 234.834 
 
 4388.5 
 
 83. 
 
 260.752 
 
 5410.6 
 
 5/8 
 
 209.309 
 
 3486.3 
 
 7/8 
 
 235.227 
 
 4403 . 1 
 
 1/8 
 
 261.145 
 
 5426.9 
 
 3/4 
 
 209.701 
 
 3499.4 
 
 75. 
 
 235.619 
 
 4417.9 
 
 1/4 
 
 261.538 
 
 5443.3 
 
 7/8 
 
 210.094 
 
 3512.5 
 
 1/8 
 
 236.012 
 
 4432.6 
 
 3/8 
 
 261.930 
 
 5459.6 
 
 67. 
 
 210.487 
 
 3525.7 
 
 1/4 
 
 236.405 
 
 4447.4 
 
 V2 
 
 262.323 
 
 5476.0 
 
 Vs 
 
 210.879 
 
 3538.8 
 
 3/8 
 
 236.798 
 
 4462.2 
 
 5/8 
 
 262.716 
 
 5492.4 
 
 V4 
 
 211.272 
 
 3552.0 
 
 1/2 
 
 237.190 
 
 4477.0 
 
 3/4 
 
 263.108 
 
 5508.8 
 
 3/8 
 
 211.665 
 
 3565.2 
 
 5/8 
 
 237.583 
 
 4491.8 
 
 7 /8 
 
 263.501 
 
 5525.3 
 
 V2 
 
 212.058 
 
 3578.5 
 
 3/4 
 
 237.976 
 
 4506.7 
 
 84. 
 
 263.894 
 
 5541.8 
 
 5/8 
 
 212.450 
 
 3591.7 
 
 7/8 
 
 238.368 
 
 4521.5 
 
 Vs 
 
 264.286 
 
 5558.3 
 
 3/4 
 
 212.843 
 
 3605.0 
 
 76. 
 
 233.761 
 
 4536.5 
 
 1/4 
 
 264.679 
 
 5574. 8 
 
 7/8 
 
 213.236 
 
 3618.3 
 
 1/8 
 
 239.154 
 
 4551.4 
 
 3/8 
 
 265.072 
 
 5591.4 
 
 68. 
 
 2 1 3 . 628 
 
 3631.7 
 
 V4 
 
 239.546 
 
 4566.4 
 
 !/2 
 
 265.465 
 
 5607.9 
 
 1/8 
 
 214.021 
 
 3645.0 
 
 3/8 
 
 239.939 
 
 4581.3 
 
 5/8 
 
 265.857 
 
 5624.5 
 
 1/4 
 
 214.414 
 
 3653.4 
 
 !/2 
 
 240.332 
 
 4596.3 
 
 3/4 
 
 266.250 
 
 5641.2 
 
 3/8 
 
 214.806 
 
 3671.8 
 
 5/8 
 
 240.725 
 
 4611.4 
 
 7/8 
 
 266.643 
 
 5657.8 
 
 1/2 
 
 215. 199 
 
 3685.3 
 
 3/4 
 
 241.117 
 
 4626.4 
 
 85. 
 
 267.035 
 
 5674.5 
 
 5/8 
 
 215.592 
 
 3698.7 
 
 7/8 
 
 241.510 
 
 4641.5 
 
 1/8 
 
 267.428 
 
 5691.2 
 
 3/4 
 
 215.984 
 
 3712.2 
 
 77. 
 
 241.903 
 
 4656.6 
 
 1/4 
 
 267.821 
 
 5707.9 
 
 7/8 
 
 216.377 
 
 3725.7 
 
 1/8 
 
 242.295 
 
 4671.8 
 
 3/8 
 
 268.213 
 
 5724.7 
 
 69. 
 
 216.770 
 
 3739.3 
 
 V4 
 
 242.688 
 
 4686.9 
 
 1/2 
 
 26*. 606 
 
 5741.5 
 
 1/8 
 
 217.163 
 
 3752.8 
 
 3/8 
 
 243.031 
 
 4702.1 
 
 5/8 
 
 263.999 
 
 5758.3 
 
 1/4 
 
 217.555 
 
 3766.4 
 
 1/2 
 
 243.473 
 
 4717.3 
 
 3/4 
 
 269.392 
 
 5775.1 
 
 3/8 
 
 217.948 
 
 3780.0 
 
 5/8 
 
 243.866 
 
 4732.5 
 
 7/8 
 
 269.784 
 
 5791.9 
 
 1/2 
 
 218.341 
 
 3793.7 
 
 3/4 
 
 244.259 
 
 4747.8 
 
 86. 
 
 270.177 
 
 5808.8 
 
 5/8 
 
 218 733 
 
 3807.3 
 
 7/8 
 
 244.652 
 
 4763.1 
 
 V8 
 
 270.570 
 
 5825.7 
 
 3/4 
 
 219.126 
 
 3821.0 
 
 78. 
 
 245.044 
 
 4778.4 
 
 1/4 
 
 270.962 
 
 5842.6 
 
 7 /8 
 
 219.519 
 
 3834.7 
 
 1/8 
 
 245.437 
 
 4793.7 
 
 3/8 
 
 271.355 
 
 5859.6 
 
 70. 
 
 219.911 
 
 3848.5 
 
 1/4 
 
 245.830 
 
 4809.0 
 
 1/2 
 
 271.748 
 
 5876.5 
 
 V8 
 
 220.304 
 
 3862.2 
 
 3/8 
 
 246.222 
 
 4824.4 
 
 5/8 
 
 272.140 
 
 5893.5 
 
 1/4 
 
 220.697 
 
 3876.0 
 
 1/9 
 
 246.615 
 
 4839.8 
 
 3/4 
 
 272.533 
 
 5910.6 
 
 3/8 
 
 221.090 
 
 3889.8 
 
 5 /8 
 
 247.008 
 
 4855.2 
 
 7/8 
 
 272.926 
 
 5927.6 
 
 !/2 
 
 221.482 
 
 3903.6 
 
 3/4 
 
 247 400 
 
 4870.7 
 
 87. 
 
 273.319 
 
 5944.7 
 
 5/8 
 
 221.375 
 
 3917.5 
 
 7/8 
 
 247.793 
 
 4886.2 
 
 1/8 
 
 273.711 
 
 5961.8 
 
 3/< 
 
 222.268 
 
 3931.4 
 
 79. 
 
 248. 186 
 
 4901.7 
 
 1/4 
 
 274.104 
 
 5978.9 
 
 7/8 
 
 222.660 
 
 3945 3 
 
 */8 
 
 248.579 
 
 4917.2 
 
 3/8 
 
 274.497 
 
 5996.0 
 
 71. 
 
 223.053 
 
 3959 2 
 
 V4 
 
 248.971 4932.7 
 
 V2 
 
 274.889 
 
 6013.2 
 
 Vs 
 
 223.446 
 
 3973 1 
 
 3/8 
 
 249.364 4948.3 
 
 5/8 
 
 275.282 
 
 6030.4 
 
 V4 
 
 223.838 
 
 3987.1 
 
 1/2 
 
 249.757 4963.9 
 
 3/4 
 
 275.675 
 
 6047.6 
 
244 
 
 MC ANDREW'S FLOATING SCHOOL 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 Diam 
 
 Circum 
 
 Area. 
 
 Diam 
 
 Circum. 
 
 Area. 
 
 877/8 
 
 276.067 
 
 6064.9 
 
 957/s 
 
 301.200 
 
 7219.4 
 
 130 
 
 408.41 
 
 13273.23 
 
 88. 
 
 276.460 
 
 6082.1 
 
 96. 
 
 301.593 
 
 7238.2 
 
 131 
 
 411.55 
 
 13478 22 
 
 Vs 
 
 276.853 
 
 6099.4 
 
 V8 
 
 301.986 
 
 7257.1 
 
 132 
 
 414.69 
 
 13684.78 
 
 1/4 
 
 277.246 
 
 6116.7 
 
 1/4 
 
 302.378 
 
 7276.0 
 
 133 
 
 417.83 
 
 13892.91 
 
 3/8 
 
 277.638 
 
 6134.1 
 
 3/8 
 
 302.771 
 
 7294.9 
 
 134 
 
 420.97 
 
 14102.61 
 
 V2 
 
 278.031 
 
 6151.4 
 
 1/2 
 
 303. 164 
 
 7313.8 
 
 135 
 
 424.12 
 
 14313.88 
 
 5/8 
 
 278.424 
 
 6168.8 
 
 5/8 
 
 303.556 
 
 7332.8 
 
 136 
 
 427.26 
 
 14526.72 
 
 3/4 
 
 278.816 
 
 6186.2 
 
 3 /4 
 
 303.949 
 
 7351.8 
 
 137 
 
 430.40 
 
 14741. 14 
 
 7/8 
 
 279.209 
 
 6203 . 7 
 
 7/8 
 
 304.342 
 
 7370.8 
 
 138 
 
 433.54 
 
 14957. 12 
 
 89. 
 
 279.602 
 
 622 1 . 1 
 
 97. 
 
 304.734 
 
 7389.8 
 
 139 
 
 436.68 
 
 15174.68 
 
 1/8 
 
 279.994 
 
 6238.6 
 
 1/8 
 
 305.127 
 
 7400.9 
 
 140 
 
 439.82 
 
 15393.80 
 
 V4 
 
 280.387 
 
 6256. 1 
 
 1/4 
 
 305.520 
 
 7420.0 
 
 141 
 
 442 . 96 
 
 15614.50 
 
 3/8 
 
 280.780 
 
 6273.7 
 
 3/8 
 
 305.913 
 
 7447.1 
 
 142 
 
 446.11 
 
 15836.77 
 
 V2 
 
 281.173 
 
 6291.2 
 
 yl 
 
 306.305 
 
 7466.2 
 
 143 
 
 449.25 
 
 16060.61 
 
 5/8 
 
 281.565 
 
 6308.8 
 
 5/8 
 
 306.698 
 
 7485 . 3 
 
 144 
 
 452.39 
 
 16286.02 
 
 3/4 
 
 281.958 
 
 6326.4 
 
 3/4 
 
 307.091 
 
 7504.5 
 
 145 
 
 455.53 
 
 16513.00 
 
 7/8 
 
 282.351 
 
 6344. 1 
 
 7/8 
 
 307.483 
 
 7523.7 
 
 146 
 
 458.67 
 
 16741.55 
 
 90. 
 
 282.743 
 
 6361.7 
 
 98. 
 
 307.876 
 
 7543.0 
 
 147 
 
 461.81 
 
 16971.67 
 
 1/8 
 
 283. 136 
 
 6379.4 
 
 V8 
 
 308.269 
 
 7562.2 
 
 148 
 
 464.96 
 
 1 7203 . 36 
 
 1/4 
 
 283.529 
 
 6397.1 
 
 1/4 
 
 30S.661 
 
 7581.5 
 
 149 
 
 468.10 
 
 17436.62 
 
 3/8 
 
 283.921 
 
 6414.9 
 
 3/8 
 
 309.054 
 
 7600.8 
 
 150 
 
 471.24 
 
 17671.46 
 
 V2 
 
 284.314 
 
 6432.6 
 
 1/2 
 
 309.447 
 
 7620. 1 
 
 151 
 
 474.38 
 
 17907.86 
 
 5/8 
 
 284.707 
 
 6450.4 
 
 5/8 
 
 309.840 
 
 7639.5 
 
 152 
 
 477.52 
 
 18145.84 
 
 3/4 
 
 285.100 
 
 6468.2 
 
 3/4 
 
 310.232 
 
 7658.9 
 
 153 
 
 480.66 
 
 18385.39 
 
 7/8 
 
 285.492 
 
 6486.0 
 
 7/8 
 
 310.625 
 
 7678.3 
 
 154 
 
 483.81 
 
 8626.50 
 
 91. 
 
 285.885 
 
 6503.9 
 
 99. 
 
 311.018 
 
 7697.7 
 
 155 
 
 486.95 
 
 8869.19 
 
 1/8 
 
 286.278 
 
 6521.8 
 
 1/8 
 
 311.410 
 
 7717. 1 
 
 156 
 
 490.09 
 
 9113.45 
 
 1/4 
 
 286.670 
 
 6539.7 
 
 1/4 
 
 311.003 
 
 7736.6 
 
 157 
 
 493.23 
 
 9359.28 
 
 3/8 
 
 287.063 
 
 6557.6 
 
 3/8 
 
 312. 196 
 
 7756.1 
 
 158 
 
 496.37 
 
 9606.68 
 
 1/2 
 
 287.456 
 
 6575.5 
 
 1/2 
 
 312.588 
 
 7775.6 
 
 159 
 
 499.51 
 
 9855.65 
 
 5/8 
 
 287.848 
 
 6593.5 
 
 5/8 
 
 312.981 
 
 7795.2 
 
 160 
 
 502.65 
 
 20106.19 
 
 3/4 
 
 288.241 
 
 6611.5 
 
 3 /4 
 
 313.374 
 
 7814.8 
 
 161 
 
 505.80 
 
 20358.31 
 
 7/8 
 
 288.634 
 
 6629.6 
 
 7/8 
 
 313.767 
 
 7834.4 
 
 162 
 
 508.94 
 
 20611.99 
 
 93. 
 
 289.027 
 
 6647.6 
 
 100 
 
 314.159 
 
 7854.0 
 
 163 
 
 512.08 
 
 20867.24 
 
 V8 
 
 289.419 
 
 6665 . 7 
 
 101 
 
 317.30 
 
 8011.85 
 
 164 
 
 5 1 5 . 22 
 
 21124.07 
 
 1/4 
 
 289.812 
 
 6683 . 8 
 
 102 
 
 320.44 
 
 8171.28 
 
 165 
 
 518.36 
 
 21382.46 
 
 3/8 
 
 290.205 
 
 6701.9 
 
 103 
 
 323.58 
 
 8332.29 
 
 166 
 
 521.50 
 
 2 1 642 . 43 
 
 1/2 
 
 290.597 
 
 6720. 1 
 
 104 
 
 326.73 
 
 8494.87 
 
 167 
 
 524.65 
 
 21903.97 
 
 5 /8 
 
 290.990 
 
 6738.2 
 
 105 
 
 329.87 
 
 8659.01 
 
 168 
 
 527.79 
 
 22167.08 
 
 3 /4 
 
 291.383 
 
 6756.4 
 
 106 
 
 333.01 
 
 8824.73 
 
 169 
 
 530.93 
 
 22431.76 
 
 78 
 
 291.775 
 
 6774.7 
 
 107 
 
 336.15 
 
 8992.02 
 
 170 
 
 534.07 
 
 22698.01 
 
 93. 
 
 292.168 
 
 6792.9 
 
 108 
 
 339.29 
 
 9160.88 
 
 171 
 
 537.21 
 
 22965 . 83 
 
 Vi 
 
 292.561 
 
 6811.2 
 
 109 
 
 342.43 
 
 9331.32 
 
 172 
 
 540.35 
 
 23235.22 
 
 V4 
 
 292 954 
 
 6829.5 
 
 110 
 
 345.58 
 
 9503.32 
 
 173 
 
 543.50 
 
 23506.18 
 
 3/8 
 
 293.346 
 
 6847.8 
 
 
 343.72 
 
 9676.89 
 
 174 
 
 546.64 
 
 23778.71 
 
 V2 
 
 293.739 
 
 6866. 1 
 
 112 
 
 351.86 
 
 9852.03 
 
 175 
 
 549.78 
 
 24052.82 
 
 5/8 
 
 294.132 
 
 6884.5 
 
 113 
 
 355.00 
 
 0028.75 
 
 176 
 
 552.92 
 
 4328.49 
 
 3/4 
 
 294.524 
 
 6902.9 
 
 114 
 
 353.14 
 
 0207.03 
 
 177 
 
 556.06 
 
 4605.74 
 
 r/l 
 
 294.917 
 
 6921.3 
 
 115 
 
 361.28 
 
 0386.89 
 
 178 
 
 559.20 
 
 4884.56 
 
 94. 
 
 295.310 
 
 6939.8 
 
 116 
 
 364.42 
 
 0568.32 
 
 179 
 
 562.35 
 
 5164.94 
 
 1/8 
 
 295 . 702 
 
 6958.2 
 
 117 
 
 367.57 
 
 0751.32 
 
 180 
 
 565.49 
 
 5446.90 
 
 !/4 
 
 296.095 
 
 6976.7 
 
 118 
 
 370.71 
 
 0935.88 
 
 in 
 
 568.63 
 
 5730.^3 
 
 3/8 
 
 296.488 
 
 6995 . 3 
 
 119 
 
 373.85 
 
 1122.02 
 
 182 
 
 571.77 
 
 6015.53 
 
 1/2 
 
 296.881 
 
 7013.8 
 
 120 
 
 376.99 
 
 1309.73 
 
 183 
 
 574.91 
 
 6302.20 
 
 5/8 
 
 297.273 
 
 7032.4 
 
 121 
 
 380.13 
 
 1499.01 
 
 184 
 
 578.05 
 
 6590.44 
 
 34 
 
 297.666 
 
 7051.0 
 
 122 
 
 383.27 
 
 1689.87 
 
 185 
 
 581.19 
 
 6880.25 
 
 7/8 
 
 298.059 
 
 7069.6 
 
 123 
 
 386.42 
 
 1882.29 
 
 186 
 
 584.34 
 
 7171.63 
 
 95. 
 
 298.451 
 
 7088.2 
 
 124 
 
 389.56 
 
 2076.28 
 
 187 
 
 587.48 
 
 7464.59 
 
 1/8 
 
 298.844 
 
 7106.9 
 
 125 
 
 392.70 
 
 2271.85 
 
 188 
 
 590.62 
 
 7759.11 
 
 1/4 
 
 299.237 
 
 7125.6 
 
 126 
 
 395.84 
 
 2468.98 
 
 189 
 
 593 . 76 
 
 8055.21 
 
 3/8 
 
 299 629 
 
 7144.3 
 
 127 
 
 398.98 
 
 2667.69 
 
 190 
 
 596.90 
 
 8352.87 
 
 I/O 
 
 300.022 
 
 7163.0 
 
 128 
 
 402 . 1 2 
 
 2867.96 
 
 191 
 
 600.04 
 
 8652. 11 
 
 5/8 
 
 300.415 
 
 7181.8 
 
 129 
 
 405.27 
 
 3069.81 
 
 192 
 
 603.19 
 
 8952.92 
 
 3/4 
 
 300.807 
 
 7200.6 
 
 
 
 
 
 
 
USEFUL TABLES FOR MARINE ENGINEERS 245 
 
 WEIGHT OF RODS, BARS, PLATES, TUBES, AND SPHERES 
 OF DIFFERENT MATERIALS. 
 
 Notation: 6 = breadth, t = thickness, s = side of square. D = ex- 
 ternal diameter, d = internal diameter, all in inches. 
 
 Sectional areas: of square bars = s 2 ; of flat bars = U; of round rods 
 = 0.7854 > 2 ; of tubes = 0.7854 (Z>* - d 2 ) = 3.1416 (Dt - *). 
 
 Volume of 1 foot in length: of square bars = 12s 2 ; of flat bars = I2bt- 
 of round bars = 9.4248D 2 ; of tubes = 9.4248 (> 2 - d 2 ) = 37.699 (Dt - t 2 ), 
 in cu. in. 
 
 Weight per foot length = volume X weight per cubic inch of mate- 
 rial. Weight of a sphere = diam. 3 X 0.5236 X weight per cubic inch. 
 
 Material. 
 
 d- 
 -OQ 
 
 32U 
 
 & 
 
 fa 
 
 I- 
 
 n 
 
 
 5^_5 
 
 Cast iron 
 
 Wrought iron 
 
 Steel 
 
 Copper & Bronze 
 (copper and tin) 
 
 Lead 
 
 Aluminum 
 
 Glass 
 
 Pine wood, dry. . 
 
 7.218 
 
 7.7 
 
 7.854 
 
 8.855 
 
 8.393 
 
 11.33 
 2.67 
 2.62 
 0.481 
 
 450. 
 480. 
 489.6 
 
 552. 
 
 523.2 
 
 709.6 
 166.5 
 163.4 
 30.0 
 
 37.5 
 
 40. 
 
 40.8 
 
 46. 
 
 43.6 
 
 59.1 
 13.9 
 13.6 
 2.5 
 
 31/8 
 
 \y 
 
 3.833 
 
 3.633 
 
 4.93 
 1.16 
 1 13 
 0.21 
 
 31/8 
 ft 
 3.833 
 
 3.633 
 
 4.93 
 1.16 
 1.13 
 0.21 
 
 .2604 
 .2779 
 .2833 
 
 .3195 
 
 .3029 
 
 .4106 
 .0963 
 .0945 
 .0174 
 
 15-16 
 
 I. 
 
 1.02 
 
 1.15 
 
 1.09 
 
 1.48 
 0.347 
 0.34 
 1-16 
 
 2.454 
 2.618 
 2.670 
 
 3.011 
 
 2.854 
 
 3.870 
 0.908 
 0.891 
 0.164 
 
 .1363 
 .1455 
 .1484 
 
 .1673 
 
 .1586 
 
 .2150 
 .0504 
 .0495 
 .0091 
 
 Weight per cylindrical in., 
 last col. + 12. 
 
 1 in. long, = coefficient of Z> 2 in next to 
 
 Republished by permission of Messrs. John Wiley & Sons, Inc. 
 from Kent's Mechanical Engineers Pocket- Book. 
 
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See Opposite Page 
 
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 (251) 
 
An Engineer's License 
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 Supplement your reading of "McAndrew's Floating 
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 (252) 
 
103,000 Copies Now in Use 
 
 Kent's 
 
 Mechanical Engineers' 
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 Eighth Edition, Revised and Enlarged 
 
 By William Kent, M. E., Sc. D. 
 Mem. Am. Soc. M. E. 
 
 The 1500 pages of this book sum up 
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 (253) 
 
On page 218 Prof. McAndrew recommends to 
 his students for a good all-around text book the 
 
 THIRD EDITION OF 
 
 Practical Marine 
 Engineering 
 
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 with additional chapters on 
 
 Internal Combustion Engines 
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 This book is written for 
 
 Marine Engineers and Students 
 
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 Forced Draft Set. 
 (255) 
 
Marks and Davis Tables 
 
 and Diagrams of the Thermal Properties 
 of Saturated and Superheated Steam 
 
 By Lionel S. Marks, M.M.E., Professor of Me- 
 chanical Engineering, Harvard University, and 
 Harvey N. Davis, Ph.D., Assistant Professor of 
 Physics, Harvard University. With 8 illustrations 
 and 2 large folded diagrams. Large 8vo. 106 pp. 
 
 Diagrams Separately: (1) Total Heat-Entropy 
 Diagram; (2) Total Heat-Pressure Diagram. In 
 heavy Manila envelope. Net 40 cents. 
 
 The chief features of these new tables are (1) greater 
 accuracy; (2) greater convenience; (3) the addition of 
 large steam diagrams for the solution of problems. 
 
 (1) The principal error in all former tables has been 
 in the values of the total heat of saturated steam and in 
 the quantities deduced from the total heat. In Marks 
 and Davis 's tables new data for the total heat of satura- 
 ted steam are given from investigations by one of the 
 authors, which it is expected will give the present tables 
 permanence. 
 
 (2) The greater convenience of these tables is es- 
 pecially noticeable in the table of properties of super- 
 heated steam, which is so arranged that all the properties 
 of any stated pressure are given on one double page. 
 
 (3) The steam diagrams, it is believed, will greatly 
 facilitate the solution of a large number of problems 
 which hitherto have been soluble only by laborious cal- 
 culation or by methods of trial and error. 
 
 There are other features which will be found to be of 
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 "A remarkably well arranged and complete utilisa- 
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 the properties of steam Will be adopted as 
 
 the standard by all careful computers" THE 
 ENGINEERING EECORD. 
 
 Longmans, Green & Co. 
 
 Publishers 
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