Science fiction/horror - Survivor floating in the water leads to deaths including impalement by swordfish

Question

A ship out at sea comes across a guy floating in the water, the crew pick him up and soon, one by one, the crew starts dying in strange accidental ways. In one of the deaths, the victim is impaled by a swordfish. At the end, the guy they picked up ends up back in the ocean for a new ship to pick up.

The film goes back over deaths and you get to see what really happened to them and it alludes to the guy being the devil. It is a 70s-80s film that might have something to do with the Bermuda triangle.

Answer 1

Could it possibly be Satan's Triangle?

A USCG pilot and his winchman Haig (Doug McClure) answer an SOS call at sea and arrive at a derelict schooner called the Requoit. Haig lowers himself to the ship, where he finds three dead bodies along with one survivor, Eva (Kim Novak), cowering in the cabin. As the pilot attempts to retrieve Haig and Eva with a rescue basket, the line breaks, plunging the two into the ocean. After they swim back to the boat, the pilot informs Haig that he must return to base because his fuel is borderline. Eva and Haig spend the night on the boat, during which time she recounts the story of the storm that killed everyone else aboard. One man was hurled through a hatch; one is hanging from the ship's mast; another vanished before her eyes; and a fourth man is in an aft compartment, floating in the air. Eva attributes the deaths to supernatural causes, but Haig has a practical explanation for everything, including the man who appears to be floating in the air. In the morning, the pilot returns along ...

There's a swordfish death (the man seemingly floating). Ironically enough, it's a lot easier to find the complete movie online (although any individual link eventually gets shut down) than it is to find a trailer.

Matching points:

• Initial person picked up by the people on the yacht was a male floating in the ocean.
• Final survivor recovered after a rescue call.
• Deaths get explained.
• Impalement by swordfish
• Film was released in 1975
• Title mentions a triangle and Satan.
• It does end with the lone survivor back in the ocean, about to be picked up by another ship as he laughs sinisterly.

Parts that don't match:

• Survivor is apparently female (although later revealed to be the priest who was initially rescued and was thought dead, hanging from the mast).
• The Devil allusion happens much later, after the rescue, although Eva discusses her fear of the Devil being behind it all throughout the movie.

I found the movie mentioned in a Movies SE question (no longer available).

Answer 2

I think it might be The Bermuda Triangle from 1978.

From the Horror.com forum it describes the movie as follows:

Horror.Com description

Several people are on a yacht when they see what appears to be a priest floating on a piece of wreckage from a boat. They take him on-board, but one by one they start dying in gruesome ways (swordfish sword through the eye etc.) The Coast Guard comes to rescue them, but the priest is the only survivor. In the final scene, shot from the helicopter, you can see somebody dressed in black hanging by his neck from a mast.

Then...

The Coast Guard crewman still on the yacht radios to the helicopter "I thought you said you had the priest with you. We have him here hanging from the mast". The pilot turns around to face the "survivor" and says into his radio " if you have the priest there, who do we have here?" The camera zooms in on the priests' face as he lets out the most chilling and frightening laugh I have ever heard. The helicopter then continues flying away with the devil on board.