December 18th - On This Date - RN Submarine Service

1914	G8	Submarine HMS G8 laid down
1917	L2	Submarine HMS L2 completed
1918	L52	Submarine HMS L52 launched
1921	Montclare	Depot Ship HMS Montclare launched
1941	United	Submarine HMS United launched
1944	Turpin	Submarine HMS Turpin completed
1944	Scorcher	Submarine HMS Scorcher launched
1940	HMS Tuna	HMS Tuna attacks the Italian submarine Brin with torpedoes and gunfire in the Bay of Biscay about 55 nautical miles east of the Gironde estuary. The Italian submarine escapes unharmed. Later HMS Tuna sinks the French tug Chassiron with gunfire about 25 nautical miles west-south-west of the Gironde estuary.
1942	HMS Safari	HMS Safari sinks the Italian sailing vessel Eufrasia with gunfire in the Gulf of Hammamet, Tunisa.
1942	U-565	German submarine U-535 sinks HMS Partridge 50 miles west of Oran.
1942	Rorqual	HMS Rorqual torpedoes and damages the Italian merchant Piero Foscari in the Gulf of Gaeta, Italy north-east of Ischia island.
1943	HMS Universal	HMS Universal torpedoes and sinks the Italian merchant La Foce south of Chiavari, Genova, Italy.