This is an interesting 1977 low-budget shocker with an interesting premise: Some low-rent diving tourists on a grade z sailboat hit a mysterious relic of a ship near an island. They go ashore and discover a tattered Nazi (Peter Cushing) who gives them the bad news that the crash has awakened an inferi-like (for you Harry Potter fans) of SS soldiers who have been underwater for 30 years. These SS killing machines pursue five desperate prey as they fight for their lives.
Besides Cushing, John Carradine hams it up early as the tourist boat captain, but he's killed off early, as is Cushing. Apparently, both worked four days for $5,000. The entire budget was $200,000. A very young, gorgeous Brooke Adams plays a bikini clad diving tourist. She is the only survivor. I don't feel bad about revealing that plot point since her rescue scene comes early and the rest of the film is flashback. That robs the film of much tension since we already know who will survive and who won't.
The SS inferi are creepy, with faces that are a blend of fishbelly white and green algae. However, their uniforms seem in way too good condition to have been underwater for three decades! The film has moments that scare, but the script and several actors are weak, the script can't decide whether to be a horror film or mystery, and the killing scenes are surprisingly tame. It's worth a rental or a cheap purchase, and it has developed small cult following the past 30-plus years. Read my Plan9Crunch colleague Steve Stones' review here.
-- Doug Gibson