A Dennis Wheatley novel again was source material for the studio, this time for a non-Satanic freak-out. Gruff sea captain Eric Porter’s steamer sets a course for adventure with combustible cargo and simmering passengers including Hildegard Knef and Suzanna Leigh, only to become stuck in a sargasso sea and set upon by marauding monsters, man-eating seaweed, and—Conquistador descendants?

Print courtesy of the collection of Joe Dante, Jon Davison, and Miller Drake