The Lost Continent (1968)

A superbly weird film. Captain Lansen (Eric Porter) has a rusty old tramp freighter full of explosive cargo and a group of passengers who all have secrets. Despite a hurricane warning, Lansen ploughs across the ocean but in the storm wrecks havoc, the crew abandon ship. The survivors awake amid a mysterious hellscape of carnivorous weed. Soon they find the ship, now trapped in a graveyard of other vessels.

One of those vessels is a Spanish galleon, the survivors seeking out other crews to seize their supplies to keep their twisted society of Conquistadors led by the boy king El Supremo (Darry Reed). Lansen and his fellow survivors including Eva (Hildegard Knef) and Tony (Harry Tyler) have to battle the Conquistadors and various bizarre monsters...

A terrific monster romp though we never actually get to see the "lost continent" which is a shame as there is apparently a society of survivors living on there though we only get to see one of them, Sarah (Dana Gillespie). A bit confused but great fun.