Description
On the 11th November 1944, just off the the Lofoten Islands (Norway), HMS Venturer (P68) engaged and sank, by torpedo, U-864, sub surface. This is the only known occasion of an underwater dog fight between 2 submarines, where a submarine was sunk. Lt Launders, the skipper, did not use ASDIC because it could have betrayed his position. He fired four torpedoes in a spread and one of them struck and sank U-864. Launders was awarded a bar to his DSO for this unique action.
The HMS Venturer watch
Inspired by the torpedo aiming device.
GMT or 12 hour movement
The GMT is appropriate given submarines exist in a world where there is no night or day.