88 DEVELOPMENT OF THE THREE-PLANE NAVY 



sections to facilitate land transportation, of 180 tons surface displacement, less than 2,000 

 miles cruising radius, and carried twelve mines. The next series of the UC type had a sur- 

 face displacement of about 430 tons, 6,000 miles cruising radius and carried eighteen mines. 

 The UC type continued to increase in size until the last boats had attained a surface dis- 

 placement of 600 tons and carried twenty-five mines. It may be mentioned that some of 

 the UC type of submarines were provided with three 20-inch torpedo tubes, that about ten 

 boats of the U type were mine layers, also that all German submarines carried rapid-fire 

 gims and that the boats of the UB and UC types were armed with either one 88-mm. or 

 one 105-mm. gun. 



I will terminate this summary of the German types of submarines with a brief descrip- 

 tion of the largest of the cruising type of the U boats, the first series of seven of which were 

 transformed into so-called freight-carrying or merchant submarines, one of which, the 

 Deutschland, visited the United States in 1916. These boats were not all alike, as changes 

 were made while imder construction and while being transformed from freight carriers to 

 armed submarines. These first seven cruising submarines were about 230 feet long, with a 

 surface displacement of 1,750 tons, a submerged displacement of over 2,000 tons, with 11 

 to 12 knots surface speed, and 7 to 8 knots submerged speed. They were armed with two 

 150-mm. and two 88-mm. guns and several rapid-fire guns; they had also six torpedo tubes 

 and carried about twenty torpedoes. They had a capacity of 250 tons of oil fuel, sufficient 

 to permit them to cruise for four or five months. The Germans recognized that the speed 

 of this first series of cruiser submarines was insttfficient to permit these vessels to overhaul 

 merchantmen. 



The second series of cruiser submarines was composed of boats of increased dimensions, 

 with a length of about 350 feet, a surface displacement of about 3,000 tons, a designed sur- 

 face speed of 16 to 17 knots, and 8 to 9 knots submerged speed. The construction of these 

 vessels was commenced late in the war, and this last series of twelve cruiser submarines was 

 not ready for service until 1918. They were heavily built, so heavily that they may be con- 

 sidered as being lightly armored. I will not go into the question of the equipment of peri- 

 scopes, wireless installations, etc., of the dififerent types of submarines, except to say that 

 all German submarines were provided with excellent material of the kind and which was 

 being constantly improved; also that range finders, listening devices, etc., were generally 

 provided. 



The Allies succeeded in organizing a successful anti-submarine campaign and in pre- 

 venting Germany from winning the war through the unforeseen, unrestricted submarine cam- 

 paign. Means were found and adopted by the Allies which made the sinking with subma- 

 rines of merchant vessels not only unprofitable but also an occupation which although in the 

 beginning was considered by the German sailor as a safe one and probably as agreeable, 

 later on as one that had become extremely dangerous and was to be avoided rather than 

 sought. As the anti-submarine campaign progressed, the nerve and morale of the crews of 

 the submarines were wrecked to a point of first causing a serious loss of efficiency and 

 finally mutiny. 



To overcome the menace of defeat from the destruction accomplished by the compara- 

 tively few German submarines engaged each day in sinking merchant vessels, the total num- 

 ber in commission at any time being only about 150, it was necessary for the Allies to make 

 use of from 4,000 to 5,000 vessels, large and small, operating to find and destroy these Ger- 

 man submarines, to destroy mines laid by German submarines, and to protect ships against 

 their attacks. The vessels of the allied navies engaged in this work included 500 destroyers, 



