This 854 ton S-Class submarine was launched as S24 (SS-129)on 27th June 1922 at the Fore River Shipbuilding Company Yard in Bethlehem USA. She was 216 feet long with a beam of 20 feet and carried twelve 21 ” torpedoes for her four bow tubes. As can be seen on the above photo she also had a 4″ deck gun. She was designed for a crew of 42 and had a top speed of 13 knots with a range of 8000 miles at 10 knots. She was powered by two 600hp eight cylinder diesel engines.

S24 was in operation for the American Navy from 1923 until 10 August 1942 when she was decommissioned by the American navy. As an American submarine, she saw service in the Panama Canal, Hawaii, San Diego and Pearl Harbour before returning to her base in New London. On 10th August 1942 she was transferred under lease to the Royal Navy and renamed “P555” . She started service with the Royal Navy in October 1942 being assigned to the 7th submarine Flotilla based at Holy Loch were she was used for training purposes.  Following damage caused by a collision in the Clyde ownership was transferred back to the US Navy in May 1944. She was the first Royal Navy submarine to have a reserve officer “Lt Edward Preston Young” as a captain.

On 25th August 1947 P555 was intentionally sunk in Lyme bay as an ASDIC target.
Today she lies 3.8 miles west of Portland Bill and is largely intact sitting upright on the seabed at 45m with a deeper scour at the stern. Her propellers and deck gun were removed prior to her being sunk. Unfortunately ,as with a large number of wrecks, a lot of the brass items such as the binnacle and conning tower lights have been removed. When I first dived her there was even a pair of binoculars in the conning tower. The video link below will give you some idea of what she looked like 20 years ago.