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sailor has been replaced by the man in the fireroom or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
rm
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rrn
i
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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.
, 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
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v o3
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gW
s -a
II
8
5
|a
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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^ .
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.
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By William Kent, M. E., Sc. D.
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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
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permanence.
(2) The greater convenience of these tables is es-
pecially noticeable in the table of properties of super-
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of any stated pressure are given on one double page.
(3) The steam diagrams, it is believed, will greatly
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There are other features which will be found to be of
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