The 'A' class was a larger version of the 'Holland', but built to an all-British design following the end of Vickers' relationship with the Holland Torpedo Boat Co. The raised conning tower was fitted to all boats in the class and was a standard feature of submarine construction thereafter. As an additional safety feature the conning tower had two hatches: the upper hatch which led out onto the bridge and the lower hatch which sealed off the conning tower from the control room.A.1's commanding officer, Lieutenant Mansergh, reported that: 'She behaved well and could keep an even depth at quite moderate speed wheras the earlier boats had to be trimmed fine and kept at full speed while working submerged.' A.1 was attached to the depot ship HMS Mercury.
Reports from sea indicated that the 'A' class represented a considerable improvement on the 'Holland'.
Chief ERA Charles Sinden was killed in an explosion onboard A.5 at Queenstown on 16th February 1905. The explosion was a result of a build-up of petrol fumes inside the boat resulting from a badly packed gland in the petrol pump. When the order to start the engine to ventilate the boat was given, the fumes exploded. Four other members of A.5's crew died in the explosion.
A.7 was fitted with experimental hydroplanes on her conning tower. The boats of the 'Holland' and 'A' classes were fitted with one set of 'diving rudders' aft, as the operation of diving the boat was performed while she was stationary. As early submariners grew more experienced, they found that they could dive their craft while under way and that another set of 'diving rudders' was necessary. Conning tower hydroplanes were not a standard fitting in the 'A' class boats.
A.13 was the last of the A-boats and was the first British submarine to be fitted with a diesel engine. The engine was a Hornsby-Ackroyd six-cylinder of 500 b.h.p. The diesel was heavier than the petrol engine fitted in other boats of the class and consequently fuel stowage was reduced. Nevertheless, on passage from Barrow to Portsmouth, the engine ran for 29 and a half hours - an extremely good performance for the time.
150 hp electric motor
A13 400 hp diesel engine.
150 hp electric motor.
A13 - 11.0 sf - 8.0 sm.
Oil Supply (tons):
30 miles at 5 kts sm.
Amendments to Surface displacement were kindly pointed out by Mr. Alec Dancer of Barrow-in-Furness.