November 12, 2017

Submersible barges fitted with a drilling rig have been the first to go in the shallow waters of the Gulf of Mexico, off the coast of Morgan City, Louisiana. However several companies investigated the concept of installing legs on rigs, which could be lowered to the bottom and then downward even more to elevate the entire barge and drilling deck above the water’s surface. Colonel DeLong built several self-elevating platforms for radar towers in about 60 ft of water off the U.S. East Coast. DeLong devised a powerful pneumatic airbag gripper jacking system that could lower legs made from tubular piles, to the sea bottom, and then further hoist the unit’s barge-type hull above the surface. J. R. Mc Dermott and De Long founded The Offshore Company and built the Offshore Rig 51, the first self-elevating drilling unit to go into service in 1954. The unit was fitted with 10 legs each 6 ft in diameter and 160 ft long, with large spud cans to limit penetration into the seafloor. The same year Mr Gus, a Bethlehem design built in 1954 for C. G. Glasscock Drilling Co. became the first unit intended for 100 feet water depth operations.