When Crabbe and his divers are diving on the aircraft wreck to search for the briefcase, they come upon an aircraft engine that is supposed to be from the wreck.. the engine has no carburetor and a couple of the valve covers are missing. Obviously, this was not a running engine.
As Lt Crabb is making his first dive, the vessel in the background in the RFA Eddy Beach, this vessel was not laid down until 1950. The vessel to the foreground, the F605 was not commissioned until 1945. The movie is set in 1942.