 Throughout late 1941 and 1942 "Porpoise" operated in the Mediterranean.On 9 December a few miles south of the Peloponnese she torpedoed and badly damaged the German passenger and cargo ship , which was carrying about 2,000 UK and Dominion prisoners of war.At least 300 PoWs were killed, and the Germans beached the merchant ship at Methoni in Greece to prevent her sinking and further loss of life.