Related Clues:

• Depth-charge avoider of WWII
• One in a seagoing wolfpack
• World war sub
• American sandwich made with a long split roll
• Sub's missile
• Former maritime menace
• Seagoing wolfpack unit
• Ruin hill training with party
• Weaponized sub of WWII
• Vessel included in the so-called 'Plan Z'
• Danger at sea -- opted out, or in?
• Trooped round to get a missile
• Stealthy WWII craft
• Forbidden to rear duck inside -- it's designed to dive
• Weapon training event below hill