“A” Class.
(Completed 1904.)
A’s 5, 6, 8, 9, 10, 11, 12, 13.
These vessels are the oldest British submarines in commission. They were built at Messrs. Vickers’ works at Barrow, and have a submerged displacement of 204 tons. Their length is 150 feet. They are propelled on the surface by petrol motors of 600 H.-P. and by electric engines of 100 H.-P. when submerged. Their surface and submerged speed is 11 knots and 7 knots respectively. The cruising range, or maximum surface endurance on the fuel carried, is 400 knots at 10 knots an hour, and the endurance submerged three hours at full speed. Their armament consists of two bow tubes with four 18-inch Whitehead torpedoes. Complement: Eleven officers and men.
These vessels, which are now used almost entirely for harbour defence, can be distinguished from later types by their high conning-towers and single short periscopes. The A.7 was lost off Plymouth early in 1914, and was never raised.