You don't necessarily need to be Stephen Hawking to know upfront that "Blood Voyage" isn't going to be a great masterpiece of cinema. And yet, I - for one - cannot be very harsh for a flick that is A) a slasher-movie that came out before the slasher genre became immensely popular, B) features a uniquely claustrophobic and original setting aboard a yacht in the Pacific Ocean, and C) stars three incredibly gorgeous leading ladies that all willingly go topless!
The plot cannot be simpler. On their way to a tropical Hawaiian wedding by yacht, a group of four tourists and three crew-members are confronted with a vicious meat cleaver-wielding maniac. The culprit must be one of them, and there are a few obvious suspects, like a girl with a background of mental illnesses and a Vietnam veteran who keeps hearing voices in his head. That's it! Of course, there's a bit of additional intrigue and attempts to mislead the viewer, but it's plain obvious we're only watching this for the kills and the nudity. Actresses Laurie Rose and Midori still have a minimum of acting skills, but this girl named Mara Modair was clearly just cast for her luscious curves and measurements.
Final footnote: what I personally find even more fascinating than the film is the story behind its director Frank Mitchell. Apparently, he had been an actor since the silent movie era already and starred in nearly one hundred films. Only at the very end of his career he suddenly decided to take place in the director's seat. For a horror movie, moreover, which is a genre he never acted in. "Blood Voyage" was also his only effort as a director.