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Class overview
Builders:	Vickers at Barrow-in-Furness
Operators:	Royal Navy
Preceded by:	Holland class submarine
Followed by:	B class submarine
Ships in class:	HMS A1, HMS A2, HMS A3, HMS A4, HMS A5, HMS A6, HMS A7, HMS A8, HMS A9, HMS A10, HMS A11, HMS A12, HMS A13
General characteristics
Displacement:	190 tons surfaced 207 tons submerged
Length:	105.25 feet (32 m)
Beam:	12.75 feet (3.9 m)
Propulsion and power:	16 cylinder Wolseley 450 hp (336 kW) gasoline engine 150 horsepower (112 kW) electric motor
Speed:	maximum 10.5 knots (19 km/h) surfaced maximum 7 knots (13 km/h) dived
Range:	360 nautical miles (667 km) at 10.5 knots (19 km/h) surfaced 20 nautical miles (37 km) submerged at 5 knots (9 km/h)
Complement:	11 (2 officers and 9 ratings)
Armament:	Two 18 inch (457 mm) torpedo tubes plus two reloads

For the later A class, see Amphion class submarine

The A class was the Royal Navy's first class of British-designed submarines. Thirteen were built by Vickers at Barrow-in-Furness between 1902 and 1905 as an improvement on the US Plunger class. While there was considerable variation amongst the boats of the class, they were around 100 ft (30 m) long and displaced around 200 tons when submerged. All of the class were propelled underwater by battery-powered electric motors and on the surface by shaft-drive Wolseley petrol engines of 400 bhp (A1), 450 bhp (A2-4) or 600 bhp (A5-12). A13 had an experimental 500 bhp Vickers diesel plant, which proved unreliable.

Armament was two 18" (45 cm) torpedo tubes with four torpedoes, except for A-1 which had 1 tube and 3 torpedoes.

The first, A1 (ordered as Holland No. 6), was launched in July 1902, the last, A13, in April 1905.

A1 was sunk off Portsmouth on March 18, 1904, in collision with the liner Berwick Castle, but raised and put back into service before finally being sunk as a naval gunnery target in 1911, followed in 1912 by A3. A7 was lost in Whitsand Bay in 1914 after diving into mud. A13 was laid up in 1914 due to engine unreliability.

The remainder were used during the first world war for harbour defence, A2 and A4 - A6 at Portsmouth, A8 and A9 at Devonport, and A10-A12 at Ardrossan. All survived the war and were converted to training in 1918 and sold in 1919-1920 except for A2 which was wrecked while awaiting disposal and finally sold in 1925.

It should be noted that this unfortunate submarine class was plagued by numerous accidents and failures, with almost every boat in the class (A-1, A-3, A-4, A-5, A-7, and A-8) being involved in some sort of accident over the course of its operational history. Many of these accidents were fatal to the crew, and resulted in the decommissioning of the submarine.

• MaritimeQuest A Class Overview