Submarine X-1

Commander Bolton (Caan) has lost his submarine, the Gauntlet, in a sea battle with the Nazis in 1943. Although the survivors still blame him,he's cleared of charges and assigned to lead a top-secret training program with three experimental miniature X-1 subs, each manned by a crew of only four. Their mission: to sink the mighty battleship Lindendorf the same ship that destroyed the Gauntlet! (official distributor synopsis)