Beyond the Poseidon Adventure

An extension of the previous film, wherein a cache of adventurers return to the overturned ship to seek several fortunes.
After "The Poseidon Adventure", in which the ship got flipped over by a tidal wave, the ship drifts bottom-up in the sea. While the passengers are still on board waiting to be rescued, two rivaling salvage parties enter the ship on search for money, gold and a small amount of plutonium.