Operation Ironclad
Japanese submarines from Penang participated in the Battle of Madagascar on 29 May 1942 attacking shipping in Diego Suarez harbour. Seven Italian BETASOM submarines were adapted to carry critical matériel from the Far East ("Bagnolin", "Barbarigo", , "Giuseppe Finzi", "Reginaldo Giuliani", , and ) of which two were sunk by the Allies, two were captured at Penang by the Germans after the September 1943 Italian surrender and used by them, and a fifth was captured in Bordeaux by the Germans, but not used.