WITH OR WITHOUT BATTLESHIPS. 91 



verse torpedo tube for large submarines. Although the submarine has been in existence many 

 years, the World War demonstrated that the navies of the world had failed to recognize 

 its possibilities. 



We must recognize the defects of the submarine as follows : The two separate sys- 

 tems of propulsion, one for surface running and the other for submerged running, combined 

 with the heavy hull necessary to give strength for submergence, result in producing a ves- 

 sel which is of low surface speed for its length and displacement and of low speed and 

 small radius of action when submerged. Increases in surface speed and in radius of action, 

 on the surface, demand considerable increase in displacement. Large sized submarines re- 

 quire great depth of water for maneuvering and are also much more difificult to handle than 

 small submarines. Owing to their comparatively small reserve buoyancy and the danger of 

 damage to the watertight hull, submarines cannot safely receive much punishment from 

 artillery fire. 



Conditions of stability and weight considerations make it impossible to armor small 

 submarines, except to give them an armored conning tower. The largest submarines yet 

 constructed are only lightly armored. Some protection can be obtained by the use of trans- 

 verse watertight bulkheads in vessels of medium and of large size. Owing to low sub- 

 merged speed, the generally poor arrangement of torpedo tubes and the equipment of short- 

 range torpedoes, the submarine is a poor torpedo boat compared with surface vessels such 

 as the destroyers, except for the fact that a submerged submarine is invisible. Consequently, 

 speed and zigzagging on the part of the surface vessel are among the best defenses against 

 being torpedoed by a submarine. The air bubble wake of the torpedo fired by a submarine 

 shows the direction of the submarine to its enemies. It is now expected that inventors will 

 eliminate this tell-tale wake. 



I believe that the experiences of the war will lead to the construction of many mine- 

 laying submarines and large submarines of both the commerce-destroying or raider type 

 and of the "fleet" type. It may be found in developing these two types that they can be 

 merged into one. Submarines of these two types must have a high surface speed of 23 to 

 25 knots and a large cruising radius when on the surface, in order to be able to do the 

 work of commerce destroyers or to keep up with large naval vessels at sea. 



I will not take vip the question of any other characteristics except that of displacement. 

 I believe that the displacement of vessels of these two types will not much exceed 5,000 tons 

 as a maximum. The experiences of the war would not justify an attempt to build either 

 extremely large submarine armored cruisers or submarine battleships, both of which types 

 have been proposed by enthusiasts. 



The extensive use made of mines, particularly in restricted waters, was to be expected. 

 The use of mine-laying submarines was something new and which will now be further 

 developed. 



Torpedoes and mines sank and damaged many naval vessels, although the German sub- 

 marine torpedoing operations were principally directed against merchantmen. The Germans 

 made few attempts to torpedo large naval vessels when those vessels were screened by de- 

 stroyers. Such attempts were unsuccessful. In the beginning of the war Germany did not 

 avail herself of opportunities to use submarines to torpedo ships of the British Grand 

 Fleet when means of protecting that fleet were yet undeveloped. In all fields of operation, 

 about forty large naval vessels of the older types, built five to ten years before the war, were 

 sunk by torpedoes and mines. This number includes cruisers, armored cruisers, and predread- 

 naught battleships. In most of these sinkings the ship was sunk by the explosion of a 



