During the voyage, wartime flashbacks show the three men committing atrocities during their tour of duty in Vietnam to include the murdering of innocent villagers.

In a short period of time, Mark, Burt and Claire are gruesomely killed, leaving only Linda, Allen, and Isabel as the survivors.

Graver, who died in 2006, also explained how the executive producer, Moshe Diamant, continually interfered with the project and significantly altered Robert Aiken’s screenplay.

Diamant believed the story line was too confusing and instead demanded that Graver make a mad slasher movie, similar to Halloween but set on a yacht.

Worse, Graver explained, after he went on vacation following the conclusion of the editing, Diamant hired another editor to re-arrange the scenes, creating yet more confusion.

I got the impression that Graver and screenwriter Robert Aiken originally intended the movie to be a supernatural thriller, with the veterans' past literally coming back to haunt them (either through the ghosts of the villagers they massacred, or through possession of one of the boaters).