U.25-U.30.
(Completed 1913–14.)
These six vessels are the latest additions to the German submarine flotilla. They are vessels of 900 tons submerged displacement with heavy-oil engines of 2,000 H.-P., and electric motors of 900 H.-P. Their surface and submerged speed is 18 knots and 10 knots, respectively. The surface cruising range is 4,000 miles. Their armament consists of two bow and two stern torpedo tubes, with eight large size torpedoes, and, in addition, two 14-pdr. quick-firing guns and two 1-pdr. high-angle guns. They have wireless telegraphic apparatus on board, and are specially constructed with long superstructures and high collier-like bows to enable them to keep at sea in almost any weather. They are fitted with two or three periscopes, and also possess a small look-out cap on the top of the lofty conning-tower to facilitate an “awash” attack in the half-lights of dawn and dusk, when the periscope is almost useless. The conning-towers and decks are armoured. Their complement is 30 to 35 officers and men.