December 13th - On This Date - RN Submarine Service

1943	Statesman	Submarine HMS Statesman completed
1944	Votary	Submarine HMS Votary completed
1914	HMS B11	Lieutenant Holbrook took the HMS B-11 up the Dardanelles, probably the most heavily defended waterway in the world at the time. B-11 was, even by the standards of the First World War, a small (300 ton), under-powered (225hp electric motor) and obsolete boat dating back to 1905 and the early days of submarine development. The compass was actually mounted outside the hull and viewed through a small glass in the conning tower. Despite the treacherous current in the Straits, Holbrook successfully got through a minefield to torpedo the Turkish battleship Messudiyeh. He then managed to return safely down the Dardanelles, despite coming under fire from shore batteries and enemy torpedo boats. B-11 had been submerged for no less than nine hours - a remarkable achievement in such a primitive craft. Holbrook was awarded the Submarine Services first Victoria Cross.
1939	HMS Salmon	HMS Salmon torpedoes & damages cruisers Leipzig & Nuremburg as they cover a destroyer minelaying operation off the River Tyne
1940	HMS Truant	HMS Truant torpedoes and sinks the Italian merchant Sebastiano Bianchi south of Calabria, Italy.
1941	HMS Upright	HMS Upright torpedoes and sinks the Italian merchants Fabio Filzi and Carlo del Greco about 15 nautical miles south of Cape San Vito.
1942	WWII	The U-boat Enigma cipher has been cracked. Shark had baffled the codebreakers from the beginning of this year because of the additional rotor, which it uses. Now the Admiralty's submarine tracking room will once more be able to route convoys round the Wolfpacks
1942	HMS Umbra	HMS Umbra torpedoes and damages the German troop transport Macedonia about 5 nautical miles north of Sousse, Tunisia.
1942	HMS Rorqual	HMS Rorqual lays 11 mines off Isola d'Ischia near Naples, Italy.
1943	HMS Unruly	HMS Unruly fires two torpedoes agaist the German auxiliary minelayer Drache off Samos, Greece. Both missed.