HMS Sea Devil was an S-class

British S class submarine (1931)

The S-class submarines of the Royal Navy were originally designed and built during the modernisation of the submarine force in the early 1930s to meet the need for smaller boats to patrol the restricted waters of the North Sea and the Mediterranean Sea replacing the British H class submarines...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. She was launched late in the Second World War, on 30 January 1945. So far she has been the only ship of the Royal Navy to bear the name Sea Devil. Her first captain was Commander Denis Woolnough Mills, who was previously First Lieutenant of HMS Thunderbolt

HMS Thetis (N25)

HMS Thetis was a Group 1 T-class submarine of the Royal Navy which served under two names. Under her first identity, HMS Thetis, she commenced sea trials on 4 March 1939. She sank during trials on 1 June 1939 with the loss of 99 lives...

.

Her late commissioning meant that she did not see much action before the end of the Second World War. She had a long life though, and by the time she was sold for breaking up, she was the last of the S-class in service with the Royal Navy, though other S-classes remained in service with other navies.

She arrived at Newhaven in February 1966 for breaking up.