A7 was a member of the first British class of submarines, although slightly larger, faster and more heavily armed than the lead ship, HMS A1.

[1] For surface running, the boats were powered by a single 16-cylinder 550-brake-horsepower (410 kW) Wolseley petrol engine that drove one propeller shaft.

[2] She sank in Whitsand Bay, Cornwall on 16 January 1914 with the loss of her crew whilst carrying out dummy torpedo attacks on Pygmy in conjunction with submarine A9.

She lies today where she sank, buried up to her waterline in a flat, mud seabed in about 121 ft (37 m) of water.

In 2014 the SHIPS Project team in Plymouth completed an archaeological investigation of the A7 submarine, having been granted a licence by the UK Ministry of Defence.