U.1 and U.2.
(Completed 1910.)
These two vessels are of the American Lake type. They have a submerged displacement of 250 tons and petrol surface motors of 720 H.-P. Their speed is 12 knots on the surface and 8 knots when submerged. The armament consists of two bow and one stern torpedo tube. This type of submarine has three special features which distinguish it from all others. It is fitted with a kind of underframe and wheels, and is designed to travel in four different positions: (1) on the surface; (2) semi-submerged, with only a look-out cowl above water; (3) submerged, with nothing but the periscope showing; (4) totally submerged and running along the sea-bed on wheels, like a submarine motor car. It is drawn down from the surface to the sea-bed by an ingenious system of wire-hawsers and drop-weights, which can be released in the event of accident. A “diving chamber” enables members of the crew to don diving-dresses and leave the submarine when on the sea-bed, for the purpose of laying or destroying submerged mines. The Lake type of submarine is also used in the Russian Navy.[[6]]