M "fllEXLlBKlS THE COORDINATION OF THE MOBILE AND COAST ARTILLERY UNITS OF THE ARMY IN THE NATIONAL DEFENSE PREPARED BY THE WAR COLLEGE DIVISION. GENERAL STAFF CORPS AS A SUPPLEMENT TO THE STATEMENT OF A PROPER MILITARY POLICY FOR THE UNITED STATES WCD 8911-9 ARMY WAR COLLEGE : WASHINGTON NOVEMBER. 1915 508 WASHINGTON GOVERNMENT PRINTING OFFICE 1916 /V / • /^-^ / '/J if War Department, Document No. 508. Office of the Chief of Staff. SYNOPSIS. I. IXTRODUCTIOX. 1. Relation between statecraft and war 5 2. Defense against over-sea invasion 5 3. Function of the Navy 5 4. Function of the Army 6 II. Functions of the Mobile and Coast Artillery Troops. 5. Two classes of troops required ^ G. Mobile troops ^ 7. Coast Artillery 6 III. Mutual Dependence op Mobile and Coast Artillery Troops. 8. Cooperation of mobile and Coast Artillery units 7 9. Landings at unfortified points 8 10. Role of movable Coast Artillery 8 11. Development of heavy movable armament in the European war 9 12. Adequate mobile troops necessarj' 10 13. Land defense of seacoast fortifications 10 30669°— No. 508 10 (3) * 667363 Digitized by the Internet Archive in 2008 with funding from IVIicrosoft Corporation http://www.archive.org/details/coordinationofmoOOunitrich THE COORDINATION OF THE MOBILE AND COAST AR- TILLERY UNITS OF THE ARMY IN THE NATIONAL DEFENSE. I. INTRODUCTION. 1. RELATION BETWEEN STATECRAFT AND WAR. In our country public opinion estimates the situation, statecraft shapes the policy, while the duty of executing it devolves upon the military and naval departments. In settling disputes under our foreign policies, the weapons of our statesmen are, first, diplomacy and, second, war; when diplomacy fails to settle the matter in dis- pute, it may be necessary to resort to war. Should such a contin- gency arise, we must be prepared to meet the enemy on sea and land. This preparation should be adequate at all times or else our national policies will be aborted or frustrated. Such preparation includes as its most vital element the development of our land and sea forces. 2. DEFENSE AGAINST OVER-SEA INVASION. The object of this study is to treat primarily of operations which will come in one way or another from the sea and to which we are most vulnerable. Consideration is therefore limited to operations possible along our seacoast, and an attempt is made to show clearly the correlative functions of the Army and the Navy and the result- ant necessity of the cooperation of the mobile and coast artillery units of our land forces so as to best utilize our means of defense, in conjunction with our Navy. •3. FUNCTION OF THE NAVY. Upon the Navy devolves the solution of the problem of securing and maintaining control of the sea. To accomplish this it must be free to take the offensive promptly, that is, to seek out and defeat the enemy fleet. The use of any part of the high-sea fleet for local defense defeats the chief object of the Navy, and is a misuse of naval power. A fleet defeated at sea and undefended by an adequate army is powerless either to prevent invasion or even its own ultimate destruction bv combined hostile land and naval forces. 508 (5) 4. FUNCTION OF THE ARMY. Upon the Army devolves the task of gaining and maintaining on shore the ascendency over hostile land and naval operations. To accomplish this it must be able to seek out promptly and to defeat, capture, or destroy the invader wherever he may attempt either to secure a footing upon our territory or to enter the waters of our harbors with the object of threatening the destruction of the seaport or of a fleet driven to seek refuge or repair therein. II. FUNCTION OF THE MOBILE AND COAST ARTILLERY TROOPS. 5. TWO CLASSES OF TROOPS REQUIRED. Experience has shown that our Army must consist of two distinct classes of troops — that is, mobile troops and coast artillery troops. Broadly speaking, the principal function of our mobile troops is to oppose an invading army., while that of our coast artillery is to oppose direct naval attacl's. 6. MOBILE TROOPS. The best defense can be accomplished only by the ability to resort to offensive operations. Our mobile troops are organized on the basis of being able to resort to offensive as well as defensive opera- tions. Some of the functions of the mobile troops are : (a) To furnish detachments of mobile forces sufficient for the protection of harbor defenses and naval bases against landing par- ties during naval raids which, under modern conditions, may pre- cede a declaration of war. (5) To oppose an invading army and to* operate in any possible theater of war. {c) To furnish adequate mobile forces to protect our principal cities by preventing the landing of hostile expeditions for their cap- ture in the intervals between our fortified harbors or near such cities. The only reasonable way in Avhich these localities not covered by fixed defenses can be defended is : (1) By providing a mobile land force of sufficient strength, so located that it may be throAvn in at threatened points at the proper time. (2) By supplying in addition modern movable coast defense ar- mament of heavy types to resist the direct naval attack of the cover- ing fleet. 7. COAST ARTILLERY. Our coast artillery is primarily organized for defensive operations. Some of its functions are : {a) To prevent naval occupation of important strategic and com- mercial harbors. 508 (&) To prevent naval bombardment of such cities and military and naval bases as are protected b}'^ seacoast fortifications. {c) To furnish a strong, fortified base from which submarines and other naval vessels, acting on the offensive, may operate. {(l) To repel a Meet supporting a landing in force within range of the guns of a fortified harbor. (e) To cooperate with th,e mobile troops in the landward defense of seacoast fortifications. With the development of modern movable artillery of large cali- ber and long range, the functions of the coast artillery will be ex- tended to repelling direct naval attack at certain unfortified harbors and favorable landing beaches in the intervals between the present fortified harbors, under the commanders of the mobile forces. III. MUTUAL DEPENDENCE OF MOBILE AND COAST ARTILLERY TROOPS. 8. COOPERATION OF MOBILE AND COAST ARTILLERY UNITS. While our Xavy retains command of the sea, the only invasion possible would come from raiding parties, limited in numbers, which an enemy fleet might land. In addition, therefore, to the coast artillery troops required to man the emplaced batteries and the mine defense of our fortified harbors, sufficient mobile troops should be provided to repel local raiding parties that might land to attack the fortifications. The personnel of the Army assigned to the fixed-gun defense, the mine defense, and the land defense in the immediate vicinity of the fortifications, may be classed while on this duty as immobile to the extent that their duties are local and pertain par- ticularly to the harbors- to which they are assigned. Thus it is manifest that a portion of our mobile troops must be used at times as fortress troops, while the development of modern high-power movable coast-defense armament of heavy types will render a portion of our coast artillery troops more or less mobile. Should our Navy lose command of the sea, the fleet wall seek ref- uge in our fortified harbors, under the protection of their guns. Here they may repair and refit, and they may be able to render valuable assistance in opposing the landing of an invading army. Assuming that our preparations are sufficient to prevent the enemy fleet from capturing the armament of our fortified harbors, running by the forts, or from resorting to distant bombardment of the cities thereon, he will be forced to attempt any landing (his only other means of inflicting damage) in the intervals between the fortified harbors. This effort can be frustrated only by adequate mobile forces held at strategic centers near the coast and rushed to the threatened points at the proper time. This force should be sufficient 508 8 in numbers, training, armament, and equipment to accomplish its purpose. In defenaing the intervals between our fortified harbors, the mov- able coast artillery becomes one of the auxiliary elements of the mobile force ; mutual dependence of the two kinds of troops along our coast line and frontier makes their cooperation imperative ; movable heavy coast artillery armament renders such cooperation more effective. 9. LANDINGS AT UNFORTIFIED POINTS. History shews that landings at unfortified points have always been effected when backed up by the fire of a fleet. This is well illustrated in the recent landings on the Gallipoli Peninsula, where the allied fleet, after being defeated in the attempt to run by or reduce the Dar- danelles batteries, supported the allied army on Gallipoli and en- abled it to land, despite the vigorous defense of the Turkish mobile forces. 10. ROLE OF MOVABLE COAST ARTILLERY. With the development and employment of large caliber movable coast artillery, it is confidently believed that at points near our coastal railroads the covering fleet may be held off at such a distance as to prevent the use of the secondary batteries in supporting the landing, which is therefore liable to be defeated by the fire of field artillery and small arms before reaching the shore. Thus it is manifest that the development of heavy movable artillery will greajtly strengthen our coast defense. This type of ordnance may be concentrated at points under attack, and when no longer required there can be rapidly shifted to other threatened points on the coast, where- its effect would be the greater in that it would be in the nature of a surprise to the enemy, thus enabling the coast artillery and heavy field artillery to cooperate with the other mobile troops in the protection of the inter- vals between the fortified harbors. The development of a heavy type of movable artillery forms another link between the coast and field artillery and between our present coast artillery and mobile troops. Unfortified anchorages and favorable landing beaches near our coastal railroads may be protected against direct naval attack; the enemy fleet may be driven out of range of the coast artillery, and the invading army deprived of the support of the fleet during the land- ing. The transports will, of course, be compelled to lower their boats out of range of these batteries, and an excellent opportunity will be given to our mobile troops to defeat the invaders before they can set foot on the shore. 508 11. DEVELOPMENT OF HEAVY MOVABLE ARMAMENT IN EUROPEAN WAR. All information from the European armies shows that the develop- ment and employment of heavy movable artillery is one of the most l^rominent features of the present European war. It has been suc- cessfully employed there in demolishing fortifications and in blasting the enemy out of his trenches, '\ATiile the general character of roads and bridges in the United States will undoubtedly operate to restrict the use of the large-caliber guns and howitzers in field warfare, there is no question of the feasibility of their employment as movable coast artillery along our coastal railroads. Descriptions given in the news- papers and illustrated periodicals and the moving pictures of war scenes and implements shown at our theaters illustrate how this heavj' movable ordnance may be thus employed. Successful tests have been made with the 1-2-inch Xavy gun mounted on specially constructed railroad car. This gun as mounted has a range of about 13 miles, and fires a projectile weighing about 800 pounds with over 200 pounds bursting charge : it is transported on and fired from its specially designed railroad car. On account of their mobility these gims can be moved rapidly to the menaced points of the coast, be immediateh' prepared for action, and when threatened by the enemy's superior artillery can retreat or change position in a minimum time. In fact, this uniting of a certain num- ber of pieces of artillery constitutes a mobile fort, powerful and economical. In addition to these heavy gun batteries, heavy how- itzers have been similarly mounted on specially constructed railroad trucks, from which they are fired without having to construct plat- forms to receive them ; the trucks are braced before firing to support the shock of discharge. In line with the above, our Ordnance Department has prepared estimates for a 11-incli gun to be transported on and fired from a specially designed railroad truck. This gun is to have a range of 30,000 yards (IT miles) and to fire a shell Aveighing 1,G(J0 pounds. The 30.5 centimeter (12-inch) Austrian Skoda mortar is practi- cally our 12-inch seacoast mortar, while the -12 centimeter (16.o-incli) mortar (Krupp) is larger than any now emplaced in our fortifica- tions; it fires a shell weighing about 1,800 pounds. Both of these types of mortars are readily transported by railroad, or over ex- ceptionally good roads and bridges by motor tractors. From photo- graphs and descriptions of these mortars and carriages it is appar- ent that heavy ordnance of this type can be effiectually employed as an adjunct to our seacoast fortl'fica.twns. These developments abroad suggest the tremendous gain the em- ployment of heavy movable artillery will give us in the defense of 508 10 our coast. In addition to the fixed defense of our fortified harbors, the employment of heavy movable artillery will make it possible to defend not only our important strategic fortified harbors and naval bases, but also to repel a hostile fleet supporting a landing in force at points on our coastal railroads. It is understood that the War Department's estimates to Congress will include 14-inch seacoast guns mounted on specially designed railroad trucks, and 16-inch mortars mounted on movable carriages. If these are provided the area of operations of our coast artillery will be materially extended. Certain unfortified anchorages and beaches favorable for landing, as well as the present fortified harbors, may be successfully defended against direct naval attack. 12. ADEQUATE MOBILE TROOPS NECESSARY. It should be understood, however, that the employment of movable coast artillery is principally against a direct naval attack, as is the employment of fixed guns in our fortified harbors and naval bases. In landing troops for an attack against a fortified harbor an enemy would naturally select a landing place out of range of its guns. Mobile troops would be necessary to defend and support the heavy guns, whether fixed, as in our fortifications, or movable, as along our railroads. The employment of heavy artillery alone could not prevent an en- terprising enemy from landing troops. Heavy movable ordnance may indeed render valuable assistance to our mobile troops in re- pelling a landing in force in the intervals between our fortified harbors, but trained mobile troops can be successfully opposed only by the employment of trained mobile troops against them. It should be borne in mind that our coast line consists almost entirely of " in- tervals." The fortified harbors are few in number and far apart. Even with the addition to our armament of heavy movable artillery along our coastal railways, there would still remain numerous long stretches of our coast line and anchorages affording facilities for landing operations which could only be opposed by mobile troops acting without the cooperation of the Coast Artillery. The United States should therefore have sufficient trained, organized, and equipped mobile troops to defeat at the coast line or frontier the army that any over-sea power could bring against us. 13. LAND DEFENSE OF SEACOAST FORTIFICATIONS. The defense of the fortified harbors on the land side must be in the hands of the mobile troops. From the time of actual investment by the enemy's army it is essential that all of the fixed armament in the seacoast fortifications capable of being used in the land de- 508 11 fense be so mounted that it may be fired landward as an adjunct of the Field Artillery as well as seaward against the hostile navy. Generally speaking, the seacoast mortars (which have all-around fire) are the only parts of the heavy fixed armament now so em- placed that they can be used in the land defense, but at all forts sus- ceptible to land attack, other elements of the fixed armament should be mounted in the future for all-around fire, where practicable, with- out sacrificing range and ade(}uate protection against naval attack. Such as are susceptible of being mounted on movable carriages shoukl be so mounted, with the largest calibers and longest ranges pos- sible of development for such mounting. To make the fire of the sea- coast armament effective against the enemy's land batteries and trenches it is essential that suitable ammunition and fuses be pro- vided, that an effective means of range and position finding be adopted : that accurate maps of the land area within the range of the fixed armament be provided, and that ample aero equipment be furnished for reconnoissance work and for correction of fire. The heavy artillery can, by the adoption of these means, use its trained personnel to the best advantage to assist the mobile troops in the defense of the fortifications. 508 O 6fiT3G5 UNIVERSITY OF CALIFORNIA UBRARY UNIVEKSITY OF CALIFOENIA LIBEARY, BERKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. Books not in demand may be renewed if application is made before expiration of loan period.