One of three surviving widows of 75 sailors who died in a submarine tragedy will unveil a new memorial later.
HMS Affray was on a training exercise off Alderney in the Channel Islands when it went missing in April 1951.
It was the last Royal Navy submarine to be lost at sea. It was found two months later 7.5 miles off the north west of Alderney at a depth of 280ft (85.3m).
Mary Henry, from Emsworth, whose husband Derek Foster died, is expected to attend a ceremony in Gosport later.
Another memorial to the tragedy was unveiled at Braye Harbour in Alderney last year.
HMS Affray left Portsmouth on 16 April, 1951 and submerged about 30 miles south of the Isle of Wight at 21:15 BST. It failed to resurface when it was due to at 08:30.
A search and rescue operation was launched, involving 26 ships and submarines along with available aircraft.
The Royal Navy’s official inquiry concluded HMS Affray sank because the snort mast, the tube through which the diesel engine “breathed” while the submarine was at periscope depth, snapped because of metal fatigue.
Source – BBC News