After a World War II-era German submarine that has been missing for 20 years is retrieved in the Bahamas by diver Mark Brittain. The wealthy Rosa Lucchesi and her partner Vic Rossiter, who have been searching for sunken Spanish galleons, hire the submarine. Eric Lauffnauer, a U-boat officer during the war, devises a plan to stage a daring million-dollar heist aboard the British ocean liner RMS Queen Mary while the ship is crossing the Atlantic Ocean. Brittain returns the submarine to operational order with the assistance of his partner Linc and new man Moreno, a war hero and expert with engines.
Disguised as officers from a British submarine on a top-secret mission, Brittain, Rossiter and Lauffnauer bluff their way aboard the Queen Mary and threaten its captain with a torpedo attack if he or his crew refuse to comply with their demands to be granted access to the cash in the ship's safe. They reach the safe and stuff large bags full of cash. After trying to wrest a valuable ring from a lady's finger, Rossiter is shot and killed by a member of the Queen Mary's crew.
The two surviving men flee the Queen Mary and reach the submarine, but Brittain must abandon the stolen money when Lauffnauer prepares to dive the submarine without him. When a U.S. Coast Guard cutter in the vicinity comes to the ocean liner's aid, Lauffnauer wants to fire the submarine's torpedoes at it, but Brittain voices strong opposition. Lauffnauer draws a gun and a scuffle ensues in which Lauffnauer accidentally shoots his friend Moreno. Lauffnauer manages to fire the torpedoes but the Coast Guard men destroy them before they can reach the cutter. Brittain, Rosa and Linc dive off the submarine just before the cutter rams into it, killing Lauffnauer. The three remaining gang members survive, paddling a raft with no loot and headed for South America.
The U.S. Coast Guard cutter seen in the film was portrayed by the Miami-based USCGC Androscoggin (WHEC-68). The USCGC Minnetonka (WHEC-67) is also listed in the film's final credits, as it was shown in some scenes. At the time of filming, Minnetonka was homeported in Long Beach, California, close to Paramount's studio facilities in Hollywood.
The Clive Cussler 1973 Dirk Pitt adventure novel The Mediterranean Caper involves a similar plot in which an international criminal using a salvaged U-boat engages in criminal enterprises.
References
^"Big Rental Pictures of 1966", Variety, 4 January 1967 p 8
