Events

1916	Swordfish / S1	Completed
1919	1886 - 1912: Pactolus	Paid off
1936	Rorqual (N74)	Launched
1940	Rorqual (N74)	HMS Rorqual hit the Italian merchant Securitas with a dud torpedo off Tulmaythah, Libya. Rorqual also lays a minefield on this day.
1943	Sickle (P224)	HMS Sickle torpedoes and damages the Italian merchant Oriani 8 miles west-north-west of Elba.
1944	Sirdar (P226)	HMS Sirdar sinks two Japanese coasters with gunfire off the west coast of Siam.
1944	Ultor (P53)	HMS Ultor torpedoes and sinks the German auxiliary submarine chaser UJ 2211/Hardy 6 nautical miles west of Genua, Italy.
1944	Vivid (P77)	HMS Vivid sinks a sailing vessel with gunfire off Monemvassia, Greece.
1959	Finwhale (S05)	Launched

The Five Streamlined T Class Submarines of the early 1950s	Read
In 1950 FOS/M received approval to commence work on streamlining older riveted boats early in 1951. The first boat, HMS Tireless was taken in hand in at the end of 1951 and apparently completed in 1952 ready for trials. Followed by the Token, Tapir, Talent and Teredo.