A World War II-era German submarine missing for 20 years is retrieved in the Bahamas by diver Mark Brittain, hired by the wealthy Rosa Lucchesi and her partner, Vic Rossiter, who have been searching for Spanish galleons.
Septembre 1942, au large de Cape Town, en Afrique du Sud. Le "RMS Laconia", qui vient de quitter le port, fait route vers l’Angleterre avec 2 000 passagers à son bord ainsi que 1 800 prisonniers italiens. Les fumées du navire sont bientôt repérées par un U-Boot. Sa taille laissant supposer qu’il peut transporter des troupes, la décision est prise de le torpiller. Cela fait, le sous-marin ne quitte pas immédiatement les lieux. Découvrant le sort des prisonniers italiens, mais aussi de civils, le capitaine, se référant à un code d’honneur maritime, ordonne l’organisation du sauvetage, arbore une croix rouge dans l’attente d’un bâtiment français envoyé par Vichy. Mille personnes seront sauvées. Peu après, ce sous-marin sera coulé par les forces alliées tandis que l’amiral allemand Dönitz signera le "Laconia order" interdisant à l’armée allemande de procéder au moindre sauvetage.
The film begins with Commander Bolton and a few surviving crew members of his 50-man submarine Gauntlet swimming ashore after unsuccessfully attacking German battleship Lindendorf. After a review, Captain Bolton is cleared of any wrongdoing and placed in charge of a small group of experimental X class submarines. His mission is to quickly train crews to man the submarines and sink the Lindendorf while it is hidden away in a Norwegian fiord.
Un homme est retrouvé assassiné sur la Tamise, l'arme du crime est un fusil-harpon, signature du mystérieux « requin » que Scotland Yard traque sans succès.
The new, state of the art nuclear submarine Seaview is on diving trials in the Arctic Ocean. The Seaview is designed and built by scientist and engineering genius Admiral Harriman Nelson (USN-Ret) (Walter Pidgeon). Captain Lee Crane (Robert Sterling) is the Seaview's Commanding Officer. One of the on-board observers is Dr. Susan Hiller (Joan Fontaine), studying crew-related stress. The mission includes being out of radio contact for 96 hours while under the Arctic ice cap, but the ice begins to crack and melt, with boulder-size pieces crashing into the ocean around the submarine. Surfacing, they discover fire burning in the sky. After the rescue of a scientist and his dog at Ice Floe Delta, Miguel Alvarez (Michael Ansara), the sub receives radio contact from Mission Director Inspector Bergan at the Bureau of Marine Exploration. He advises that a meteor shower pierced the Van Allen radiation belt causing it to catch fire, resulting in a world-threatening increase in heat all across the Earth. Nelson's on-board friend and scientist, retired Commodore Lucius Emery (Peter Lorre) concurs that it is possible. Bergan informs Nelson that the President wants him at a UN Emergency Scientific Meeting as soon as possible.
The United States and the Soviet Union have both developed technology that can miniaturize matter by shrinking individual atoms, but only for a limited amount of time, depending on how small the item is miniaturized.
Three very likeable losers fail while they pursue individual goals. Roland Darbont (Lino Ventura) is an inventor who has designed his own engine. Manu Borelli (Alain Delon) on the other hand is a pilot who prepares a spectacular stunt. Both of them are running tests on Darbont's premises when they are joined by Laetitia Weiss (Joanna Shimkus), an artist who builds abstract statues from scrap metal. They nourish each other's hopes and learn to get along with each other.
Mike Di Donato, an Italian-American man with a mysterious past, leads a solitary life in an anonymous sea island. His unusual work is the hunting of sharks, from which his partner derives handicrafts for the local market.
While scuba-diving near shipwrecks off Bermuda, vacationing couple David Sanders (Nick Nolte) and Gail Berke (Jacqueline Bisset) recover a number of artifacts, including an ampoule of amber-colored liquid and a medallion bearing the image of a woman and the letters "S.C.O.P.N." (meaning "Santa Clara, ora pro nobis" or "Saint Clara, pray for us") and a date, 1714. Sanders and Berke seek the advice of lighthouse-keeper and treasure-hunter Romer Treece (Robert Shaw) on the origin of the medallion, who identifies the item as Spanish and takes an interest in the young couple. The ampoule is noticed by the man who had rented diving equipment to Sanders and Berke, which in turn attracts the attention of Henri Cloche (Louis Gossett, Jr.), a local drug kingpin for whom the shop owner works, who unsuccessfully tries to buy the ampoule and then begins to terrorize the couple with Haitian black magic. The ampoule contains medicinal morphine from the Goliath, a ship that sank during World War II with a cargo of munitions and medical supplies. The wreck of the Goliath is considered dangerous and is posted as off-limits to divers due to the danger of explosions. Treece concludes that a recent storm has exposed her cargo of morphine and unearthed a much older wreck containing Spanish treasure.
During World War II, Navy Lt. Cmdr. John Lawrence (Richard Widmark), a strict disciplinarian, is put in charge of Underwater Demolition Team 4 after its former leader, Lt. Cmdr. Jack Cassidy, is killed in action. The unit's men are distrustful of the professionally aloof Lawrence, and the relationship immediately takes a turn for the worse when they brawl with sailors aboard their transport ship. The ship's captain, Lt. Cmdr. Pete Vincent (Gary Merrill), understands the natural resentment the elite UDT men feel over the death of Cassidy, which they have transferred to Lawrence, and offers to go easy on the team at captain's mast. The "by-the-book" Lawrence, however, elects to hold his own mast and disciplines the entire team just before a dangerous reconnaissance mission to ascertain the safest landing beach during an upcoming invasion of a Japanese-held island. Lawrence is scornfully perceived as afraid when he splits up the platoon and puts team executive officer Lt. Klinger in charge of a diversion to the more dangerous beach, where the main landing is scheduled.
Eccentric charter skipper Jim Carnahan (Wilde) and his team of hard-luck dreamers battle sharks, bandits and their own greed to recover sunken treasure off the coast of Honduras.
A Russian submarine called Спрут ("Octopus") draws too close to the New England coast one morning when its captain (Theodore Bikel) wants to take a good look at America and runs aground on a sandbar near the fictional Gloucester Island, which, from other references in the movie, is located off the coast of Cape Ann or Cape Cod, Massachusetts. Rather than radio for help and risk an embarrassing international incident, the captain sends a nine-man landing party, headed by his zampolit (Political Officer) Lieutenant Yuri Rozanov (Alan Arkin), to find a motor launch to help free the submarine from the bar. The men arrive at the house of Walt Whittaker (Carl Reiner), a vacationing playwright from New York City. Whittaker is eager to get his wife Elspeth (Eva Marie Saint) and two children, obnoxious but precocious nine and half-year-old Pete (Sheldon Collins) and three-year-old Annie (Cindy Putnam), off the island now that summer is over.
Martin, CEO of Tri-Oceanic Corp, hires geologist Steven Beck to command an undersea mining operation for six months. While working outside their deep sea station in a pressure suit, one of the crewmembers, Sixpack, discovers a Soviet shipwreck, Leviathan.
DeepStar Six is a prototype deep-sea colony funded by the United States Navy with a collection of 11 military and civilian crew members in the last week of their six month tour. The brainchild of Dr. Van Gelder, the base is allowed to conduct its experiment on underwater colonization provided that he also oversee the installation of a nuclear missile storage platform nearby. Nearing the last days of his deadline, Van Gelder's plans are threatened when geologist Burciaga (Elya Baskin) discovers a massive cavern system at the installation site. Van Gelder orders the submarine crew to use depth charges to collapse the cavern, to the dismay of Dr. Scarpelli (Nia Peeples), who wants to preserve the cavern to study the potentially primordial ecosystem she suspects lies inside.
Inspector Warren of Scotland Yard flies into Jamaica and is taken to the headquarters of the Jamaica Constabulary Force. Exchanging credentials with a Jamaican Inspector, Warren reveals he has come to seek the extradition of a wanted criminal known as "The Professor". Surprised when the Inspector refuses to extradite the Professor, the Jamaican Inspector recounts a story told in flashback.