Ocean Drilling and Exploration Co. of New Orleans, which owned the Ocean Ranger, has begun an experimental program on two of its rigs in which the captain is the ultimate commander, as on ships. "It's a substantial change for us," said company spokesman Al Spindler.

A key figure in the experiment is Robert J. Rugur, 30, of Middletown, Md., captain of the Ocean Bounty, a floating platform drilling rig off Aberdeen in the North Sea. Rugur is a new generation of offshore supervisor. A graduate of the Merchant Marine Academy, he has written an emergency-procedures manual putting himself in charge. Now enrolled in a graduate school computer course, he uses a computer for ballast-control calculations on board the rig.

"When I came aboard . . . the chain of command was open to dispute," he said in a recent interview. "I had no doubt it was me, but ODECO policy said it was the toolpusher. There was also a Shell company man. You have to listen to them or you won't have the Shell contract very long.

"Now, however, I am in charge all the time, including in charge of drilling. In an emergency, if the rig is starting to sink, I'm the one who should know what to do."

Rugur said the change was necessary because of "the mentality of the oil field" where "the toolpusher doesn't care about regulations. They have tremendous egos. But ship's captains traditionally recognize that the chief engineer knows more about engines than they do. They're used to taking advice. The trouble has been bad captains. They brought captains up from garbage scows."