The following table, in which round figures are used, will help us to appraise Germany’s progress in the construction of U-boats previous to the outbreak of hostilities. It is based on what is considered to be reliable evidence, although the difficulty of obtaining accurate figures will be appreciated. I shall refer to the larger types later.
U 1 (1905).—Submerged displacement, 236 tons. Surface engines, 250 H.P.; electric motors, 100 H.P. Speed, 10 knots on surface, 7 knots submerged. Surface range, from 700 to 800 miles. Armament, one torpedo-tube in bow. Complement, nine officers and men.
U 2–U 8 (1907–10).—Submerged displacement, 250 tons. Surface engines, 400 H.P.; electric motors, 160 H.P. Speed, 12 knots on surface, 8 knots submerged. Surface range, 1000 miles. Armament, two torpedo-tubes in bow. Fitted with submarine signalling apparatus. Complement, eleven officers and men.
U 9–U 18 (1910–12).—Submerged displacement, 300 tons. Surface engines, 600 H.P. Speed, 13 knots on surface, 8 knots submerged. Surface range, 1500 miles. Armament, two torpedo-tubes in bow, one torpedo-tube in stern. With U 13 anti-aircraft weapons were introduced.
U 19–U 20 (1912–13).—Submerged displacement, 450 tons. Surface engines, 650 H.P.; electric motors, 300 H.P. Speed, 13½ knots on surface, 8 knots submerged. Surface range, 2000 miles. Armament, two torpedo-tubes in bow, one torpedo-tube in stern, two 14–pdr. Q.F. guns. Complement, seventeen officers and men.
U 21–U 24 (1912–13).—Submerged displacement, 800 tons. Surface engines, 1200 H.P.; electric motors, 500 H.P. Speed, 14 knots on surface, 9 knots submerged. Surface range, 3000 miles. Armament, two torpedo-tubes in bow, two torpedo-tubes in stern, one 14–pdr. Q.F. gun, two 1–pdr. anti-aircraft guns. Complement, twenty-five officers and men.
The Interior of a German Submarine
Showing the internal combustion engines for surface work, and the motor-generators for driving the propellers when submerged.
U 25–U 30 (1913–14).—Submerged displacement, 900 tons. Surface engines, 2000 H.P.; electric motors, 900 H.P. Speed, 18 knots on surface, 10 knots submerged. Surface range, 4000 miles. Submerged range, 300 miles. Armament, two torpedo-tubes in bow, two torpedo-tubes in stern, two 14–pdr. Q.F. guns, two 1–pdr. anti-aircraft guns. Complement, thirty to thirty-five officers and men. Upper works lightly armoured. Fitted with wireless.
German U-boats are really submersibles. That is to say, the outer shell conforms to the shape of an ordinary ship, with a broad deck, whereas British submarines resemble a fat cigar. Internally they are cylindrical, the space intervening between the compartments and the shell affording accommodation for the ballast tanks. The theory is that vessels built to this design are more seaworthy and easier to handle. U 36, which was building when war broke out, was divided into ten compartments, below which were the steel cylinders containing compressed air for freshening the atmosphere, oil fuel, lubricating oil, and water-ballast tanks, and the accumulators for driving the dynamos when travelling beneath the surface. The officers’ combined ward-room and sleeping quarters were for’ard, immediately behind the bow torpedo compartment. Adjoining were the crew’s quarters, divided by a steel bulkhead from the control chamber, situated below the conning-tower. In the control chamber the steering wheel, periscope, projection table on which a surface view was thrown after the manner of a camera obscura, water-pressure dial, and other delicate and necessary instruments for the safety and navigation of the ship were distributed. Proceeding toward the stern, the petty officers’ quarters, the machine-room with its heavy oil engines for surface work and electric motors for progression when submerged, and the stern torpedo compartment were to be found. U 36 was one of the “new Super-Dreadnought submarines,” to quote an American correspondent who saw them under construction at Kiel. On these, he added, “the Germans appear to be banking.”