U-410 attacked Penelope during operations around the Anzio area after she left Naples, where her freedom to manoeuvre was restricted. An acoustic homing torpedo hit the aft engine room. Such torpedoes were still new and unreliable technology, so a hit was not automatic. Sixteen minutes later another torpedo struck the aft boiler room, close enough to the first impact to break the hull's integrity. Penelope sank immediately after the second hit. Of 623 people aboard, 417 were lost and 206 survived, including people beyond the normal ship's company.
Chapter · 5:33:49-5:36:00
U-410's acoustic-torpedo attack on HMS Penelope
Two torpedo hits close together in Penelope's aft machinery spaces caused a rapid sinking with heavy loss of life.