Tentacle Monster thriller!

by Rick Taylor
(Pine Bluff, AR, USA)

A buddy of mine and I both remember a movie from our childhoods, one of those late night movies made back sometime in the late 50's or early 60's.

What we can remember is that some smuggler has a ship full of some kind of explosives, and gets stuck in some kind of Sargasso sea area that has ships and descendants of the crews from at least as far back as the 15th century.

There are vine tentacles that rope in the unlucky as well as a monster of some sort. The people use balloons or some kind of contraption to walk on the vegetation choked water.

In the end the explosives (some chemical that reacts with water naturally) are used to kill the main monster and free some of the trapped people.

We'd really like to know the title of this movie because we want to see it again!