This U.1 was built as an experimental boat by the famous firm of Krupps. She has a surface displacement of 197 tons, a submerged displacement of 236 tons, and her heavy-oil surface engines are of 250 H.-P. The electric motors for submerged use develop just over 100 H.-P. The speed ranges from 10 knots an hour on the surface to 7 knots when submerged, and her surface range of action is about 700 to 800 miles. The armament consists of one bow torpedo tube and three (17.7) Schwartzkopf torpedoes are carried. The complement is nine officers and men.
The trials of the U.1 extended over a period of a year and a half, and all proved remarkably satisfactory. During the tests which took place in Eckernforder Bay she succeeded, twice in succession, in torpedoing a moving target while travelling submerged at full speed.
The uncertainty displayed for some years previous by the German Naval Authorities regarding the value of submarine boats gave place to a thorough sense of the important part these “mighty atoms” would play in future naval warfare, and to a strong determination that the German Navy should include a powerful submarine flotilla.
U.2-U.8.
(Completed 1907–10.)
These seven vessels were great improvements on the U.1. Their displacement is 210 tons on the surface and about 250 tons when submerged. They are fitted with Krupp-Nuremburg heavy-oil engines of 400 H.-P. and electric motors of 160 H.-P. Their speed on the surface is 12 knots and 8 knots when submerged. The surface range of action is 1,000 miles and the submerged endurance about three hours at full speed. Their armament consists of two bow torpedo tubes and four torpedoes are carried. The complement is eleven officers and men.
U.9-U.18.[[5]]
(Completed 1910–12.)
These ten vessels are of increased size and power, their submerged displacement being 300 tons, and the horse-power of their heavy oil surface engines is 600. The electric motors develop 200 H.-P. The surface and submerged speeds are 13 knots and 8 knots respectively. The surface range of action is 1,500 miles, and the armament consists of two bow and one stern torpedo tube with five torpedoes. The U.13 and subsequent vessels of this class are provided with a quick-firing, high-angle gun for defence against aircraft, and have sleeping accommodation for the crew. They may be termed the first German sea-going submarines. Their complement is twenty officers and men.