Deep Six (1984)

Deep Six was first released as part of the third series (1984) packaged only with the Flying Submarine (S.H.A.R.C.). 

From his Filecard:
Deep Six never won any awards for being friendly. Became a Navy diver so that "I could be alone." Enjoys bottlecap collecting, solitaire and the New York Times crossword puzzles. Only 12 out of 50 Navy divers passed the strict requirements for the coveted diver position on the Joe team. Eight washed out in the practical application testing. Of the 4 finalists, Deep Six could hold his breath the longest.

Torpedo says: "Down in the depths where light doesn't reach and the water pressure can crush you like an eggshell-that's where Deep Six likes it!"