HMS A1 was the first submarine which was designed and built in Britain. She was commissioned in 1903, but tragically lost with all hands in a collision off the Nab light in 1904.

The submarine was raised in 1904 and then used for training and experimental purposes. HMS A1 finally disappeared during an unmanned exercise, when the tow broke. Despite of extensive searches, the Royal Navy was unable to locate the submarine. The wreck was rediscovered in 1989 and designated as a historic wreck under the Protection of Wrecks Act 1973 in 1998.

Wessex Archaeology conducted a magnetometer survey, a sub bottom profiler survey and a multibeam sonar survey on the wreck site in 2003.

The results of the multibeam survey can be downloaded in the form of a movie clip (MPEG, 6MB).