The Lost Continent (1968)
 

The worst thing I can say about this film is that there are a couple of unbelievable decisions made by the characters that serve no purpose other than to allow plot conveniences. But looking past these flaws, I have to admit that I enjoyed this unique little trip of a film. This small budget flick "puts the bucks on the screen". There are good bits of gore, death by shark, a hot & slutty blond girl who needs to get f***ed regularly even though death seems imminent, a believable major plot point that explains how the ships all get brought together, and a pretty good looking rock-crab monster thing that reminded my of The Never-Ending Story. It's definitely a B-movie guy flick; sort of a cross between Barbarella and 10,000 Leagues Under the Sea...