Related Clues:

• Upper-class snake caught finally as killer down under
• Ship sinker of WWII
• WWII marine vessel
• Extremely upset about snake, an unseen attacker
• W.W. II threat
• Threat to the Allies in W.W. II
• Danger to Allied shipping
• Undersea menace could be about
• Dumb loyalty regularly needed to serve on such a vessel
• Sinking vessel, but buoyant at regular intervals
• Unseen WWII menace
• Destroyer target
• German sub dangerous to Allied ships