"The Battleship Tirpitz Matter"
Published in The Victor #274-#275, May 28 - June 4, 1966.
The German battleship Tirpitz is in dry dock but ready to be released back into the war. The British have a plan to take it out but it requires intimate knowledge of the gates to the facility, especially underwater. Captain Webb is asked to parachute near the place and conduct inspections to report back to HQ.