Riptide

"Treasure hunters have failed to find the lost treasure buried on Ragged Island's Water Pit by the English pirate Edward Ockham. Now, a new expedition using advanced computer technology and supported by millions of dollars has been mounted to find the treasure."@en
"An attempt to recover a pirate treasure from a booby-trapped hiding place, a water pit in Maine. Many have died attempting to enter it, including Martin Hatch's father and brother. Now Martin himself tries, using the latest in computer technology."
"A new high-tech expedition is mounted to discover the treasure of English pirate Edward Ockham. Will the expensive technology be enough to overcome the deadly secrets of the Water Pit on Ragged Island, Maine?"@en
"For generations, treasure hunters have searched for the key to the Water Pit, the labyrinth of shafts and tunnels that honeycombs Ragged Island. But the Pit is reluctant to give up its treasure, and many will die before its secret is revealed."@en