At midnight of Feb. 15, 1982, Capt. Ronald Duncan's supply ship was rolling wildly in a 100-mph North Atlantic blizzard. Some of the waves were 70 feet high. The air temperature was 24 degrees, the salt water, 29.

Duncan's mission was to stand by the Ocean Ranger, the world's largest floating oil-drilling rig, and endure with his crew of seven the heaving, pitching bronco ride of a howling storm 170 miles off Newfoundland. He would make no deliveries of drill pipe or food crates to the rig this night.

On the Ocean Ranger, lit up like a resort island five miles away, it would be quite different. The Ranger was a new deep-sea conception -- as square and solid as the Parthenon, which, with her eight massive supporting columns, she somewhat resembled. Towering 37 stories from keel to derrick top, moored by 12 anchors with cables each a mile long, the Ranger seemed a temple of stability. Veteran ship captains were amazed to find that she hardly rocked at all, often less than half a degree. But the oil men who ran the Ocean Ranger just propped up their cowboy boots and smiled. Well, Oklahoma didn't move around under your feet, either.

Capt. Duncan received a radio call at 1:05 a.m. It was the Ranger:

"Will you come in a little closer, please? We've got a problem here on the rig."

"Yes, certainly, I'll start coming in closer now," Duncan radioed back. The rig was a strong blip on his radar screen. "Would you like to discuss this problem with me?"

A moment later: "We are listing to port, and all countermeasures are ineffective."

When Duncan got there an hour later, he saw many tiny glowing lights in the water. The lights were attached to the lifejackets of men. A lifeboat appeared out of the driving snow and motored to his supply ship. But when six men gathered on its rail to be rescued, the lifeboat capsized and they were spilled into the sea.

The men, wearing light clothing, began losing consciousness as soon as they entered the sub-freezing water. Duncan's crew, only yards away, threw lines and floats, but the men were unable to help themselves. The lifeboat was upside down, had a hole in its bow and was split open along the bottom like a purse. Twenty men were still inside, strapped in place by their seat belts.

The Ocean Ranger capsized and sank at 3:05 a.m. Of her crew of 84, there were no survivors. Only 22 bodies were recovered.

At 6:00 that morning, in Plainfield, Conn., Gloria Blevins arose to turn on the heat. She was expecting her son Tom home that day, after his 21-day tour of duty on the Ocean Ranger. She turned on the 6:30 television news. The newscaster said the world's largest floating oil rig had sunk off Newfoundland.

Blevins remembered asking Tom to promise to wear his life jacket if anything went wrong. "Okay, Mom," he had said. "But it doesn't matter, because you've only got 5 minutes to live if you end up in the water." Resuming the Offshore Push

Between 1955 and 1974 -- the first 19 years of large-scale offshore oil and gas prospecting -- 77 workers lost their lives in accidents on floating drill rigs, according to a study by Offshore Magazine.

In the past five years, however, as the industry has ventured into deeper waters and more hostile climates in search of new petroleum reserves, four catastrophic sinkings alone have caused 360 deaths.

The lost rigs were floating prospectors, designed to drill test wells that cost as much as $30 million each but might return billions to oil companies in the event of a major strike. The United States now gets only 12 percent of its oil offshore, but by all estimates about 60 percent of its remaining oil and gas supplies lie under the ocean. The push offshore, postponed in the 1970s, has resumed in the 1980s.

A Washington Post investigation of recent offshore drilling disasters, based on interviews with oil and drilling company executives, insurance officials, workers and their families and visits to operating rigs in the Gulf of Mexico, reveals that:

*The lifeboat systems on explorer rigs do not work in the storms regularly encountered on the new drilling frontier. Ten-story-high mobile drilling platforms exposed to large seas currently provide no reliable means of self-rescue for the large crews who live on them.

*Ultimate command authority, especially on American-flag explorer rigs, is frequently divided among drillers, oil company representatives and the captain -- a condition at variance with seagoing tradition and criticized by the Coast Guard as potentially hazardous.

*A recommendation from the National Transportation Safety Board in 1978 to require exposure suits for crewmen in frigid waters was at the time rejected by the Coast Guard as an "unnecessary additional cost burden on the operator." The suits, which cost about $300 each and protect against the rapid loss of body heat believed to have killed the Ranger crew, were made mandatory in August. Expanding the Search

When it sank, the Ocean Ranger was the pride of an offshore exploration fleet committed to search "farther and deeper" for oil and gas reserves. Until 1982 only 2 percent of U.S. underwater tracts had been explored. That was the year wholesale test drilling of the outer continental shelf was invited by the Reagan administration's controversial five-year, area-wide leasing plan.

The opening up of U.S. waters for drilling drew home the far-ranging exploration fleet and revitalized an industry in the grip of a severe slump. Of the world total of 725 mobile rigs, 206 of them were drilling this month in the Gulf of Mexico alone -- a 64 percent increase over last year.

So far no substantial new deposits have been found.

Instead the explorers have found hazard.

On four recent occasions the sea has swallowed up the farthest and deepest prospectors. In China, in 1979, the floating rig Bohai 2 sank in a storm with 72 deaths -- the result of safety deficiencies for which the Chinese minister of petroleum was fired. The next year, in the North Sea, Norway's giant floating platform "Alexander L. Kielland" lost a buoyancy column and capsized, killing 123 of the 212 aboard.

Eight months after the loss of the Ocean Ranger in 1982, the American drillship Glomar Java Sea sank in a typhoon in the China sea, killing her crew of 81. Nor are the largest fixed installations immune: In August, an explosion blasted apart Brazil's Enchova Platform north of Rio De Janiero. Thirty-seven men aboard the 50-story structure were killed as they tried to escape in lifeboats.

The death toll in the Ocean Ranger and Glomar Java Sea sinkings was in each case the largest number of civilian maritime deaths on American-flag seagoing vessels since the Morro Castle burned at Asbury Park, N.J., in 1934, an event that led to basic changes in safety requirements for passenger ships.

Change has come slowly to the offshore industry, however. The Brazilians were said to be pushing hard to make a quota of 500,000 barrels a day. The Chinese oil supervisors, according to the Daily Worker, ignored gale warnings and were guilty of "brash leadership," labeling anyone who "took a scientific viewpoint" as being "afraid of difficulties." The operators of the Glomar Java Sea ignored warnings of an approaching typhoon. The Ocean Ranger was supposed to be evacuated in the face of a severe storm, and despite accurate forecasts, evacuation was never discussed.

Safety offshore remains a delicate balance of prudence and profit, with the scales weighed by the industry. Regulations, the U.S. Coast Guard says, are intended only to set minimal standards.

Asked why $300 exposure suits were not required aboard a $125 million drill rig in freezing waters, Ralph Johnson, chief of marine operations of the NTSB, replied: "My answer to that is that by 1978 we felt the state of the art on exposure suits was such that they should be put aboard. But to pass regulations you have to show a need. In safety, the way you show a need is with a disaster. The public is very concerned when an Air Florida jet crashes into the 14th Street Bridge, but actually more people were lost on the Ocean Ranger." Calculating Acceptable Risk

What sank the Ocean Ranger?

The Coast Guard investigation cited a "chain of events that . . . could have been broken by competent human intervention." The NTSB inquiry, congressional hearings and a Canadian investigation came to much the same conclusion.

Numerous violations of safety regulations were cited, including the failure after two years by the rig owner, Ocean Drilling and Exploration Co. of New Orleans (ODECO), to complete the installation of Coast Guard-approved lifeboats. In the end, two fines were levied. For permitting the Ocean Ranger's Certificate of Inspection to expire, the drilling company paid $25,000, the maximum penalty. For ignoring requirements to have seven Coast Guard-certified lifeboatmen aboard -- the Ranger had three -- the fine was $100.

But the root cause of the disaster was not just a storm or a broken porthole or a series of human errors; there had been storms and human error before. Instead, the fate of the Ocean Ranger seems to have been inextricably tied to the new hazards of frontier drilling, and the offshore industry's concept of acceptable risk.

The acceptance of risk, financial and personal, lies at the heart of the robust and adventuresome exploration industry. The tradition was born not at sea but in the dusty oil patches of the American southwest and later successfully transferred to the warm shallows of the Gulf after World War II. Entrepreneurial spirit and a sense of destiny made the venture offshore a muscular, typically American new industry -- an approach and an expertise that was quickly exported all over the world.

The early days of mud-flat drilling were rough and tumble, but as technology took exploration over the horizon, sophisticated systems of risk analysis developed. By 1983, the Gulf Oil's frontier technology experts were able to predict the consequences of a floating rig being rammed by an ocean liner (70 percent chance of major damage; 10 percent chance of sinking); or underwater drilling pipe being struck by a submarine (98 percent chance of a serious well explosion if the submarine hits the pipe squarely).

The prospect of loss of life presented a different kind of problem.

"The acceptance of risk is delicate," two professors from the Norwegian Institute of Technology observed in a paper delivered in 1981 in Ottawa, because "society is less inclined to accept risks in new activities than the traditional risks we are accustomed to . . . . We are much more scared" by multiple-death accidents than by single-death accidents that occur everyday, "e.g. on the roads."

The Ocean Ranger was believed by its owners to be virtually unsinkable. Coast Guard regulations regarding lifeboats, life rafts, life jackets and lifeboat operators were not complied with, government investigations showed. As for exposure suits, ODECO spokesman Al Spindler said: "We just didn't know about them. After the tragedy, the president of the company said, 'My God, if we had known about such a thing . . . . ' "

The rubber garments had been manufactured by more than 20 companies since the mid-1970s. By 1980, thousands were in use by coastal fishermen and sportsmen in northern waters, and hundreds of mariners had reported that they owed their lives to the suits. According to the Imperial Survival Suit Co., a person wearing an exposure suit can survive 13 hours in 32-degree water. Without such protection, immobilization occurs almost immediately and death after 15 minutes.

Eight months before the Ranger sank,the Canada Oil and Gas Lands Administration (COGLA) issued a telex to all offshore operators recommending that exposure suits be installed on rigs. "The industry and COGLA did not move quickly in implementing this recommendation," the Canadian Royal Commission concluded.

The House Committee on Merchant Marine and Fisheries, after holding hearings on the loss of the Ranger, informed the Coast Guard that although " . . . numerous examples exist of the voluntary use of exposure suits by commercial and research vessels operating in frigid waters . . . the offshore oil and gas industry has failed to make routine use of this equipment."

Asked why suits did not find acceptance in the offshore industry, Robert Markel, chief of survival systems for the Coast Guard, said: "It's simple. Exposure suits don't earn any money."

Three months after the Ocean Ranger sank, the owners ordered 4,300 suits at a cost of $1.4 million, enough for all 42 of its exploration drilling rigs -- those in warm waters as well as cold. 'There Is Broken Glass in Here'

What happened on the Ocean Ranger between the mayday call and the capsize will never be precisely known.

The chain of events that led to the sinking began the day before, on Feb. 14, with weather forecasts of a major storm with winds of 100 mph and seas averaging 40 feet.

Although the drilling company's emergency-procedures manual stated that partial or complete evacuation by helicopter was to be considered in advance of any storm with predicted winds of 100 mph or more, neither the Ranger crew nor shoreside supervisors discussed evacuation at any point, according to the investigations. In her seven years, the Ranger had weathered 50 major storms, the worst only a month before.

By 4 p.m., with a neighboring rig reporting 110-mile-an-hour winds and worsening seas, the Ranger was taking spray on the drilling floor more than eight stories above the water. Drilling was halted.

Some three hours later, two smaller drill rigs nearby and several supply boats began to overhear internal radio exchanges aboard the Ranger.

The captain of the rescue boat Boltentor provided the best clue, recalling in testimony:

"A voice said, 'well, there is broken glass in here, and there is water in here.' And another voice said . . . 'get some guys in there and get it cleaned up.' Then . . . a third voice said, 'well there is some high-powered cables down there.' And the second voice came back and said, 'well, don't have anybody injured or killed, but obviously still get the water cleaned up.' And the last thing I heard was another voice saying, 'well, there is some valves operating or opening or closing.' "

A massive wave, perhaps containing a piece of debris or ice, had smashed a porthole in the rig's ballast-control room. Water had splashed on electrical panels, causing short-circuits. The valves "opening and closing" were doing so of their own accord -- and they were the valves that controlled the level attitude of the rig. The massive structure began to tilt forward.

Yet the crew did not seem concerned.

The Ocean Ranger had not deballasted her tanks to rise to "survival draft," a basic cautionary maneuver that would have increased her height above the sea by five to 10 feet. The crew did attempt to override the "automatic" action of the ballast valves, but they only made matters worse. Neither the captain nor the chief drilling superintendent reported any problems to shore, according to radio logs.

As the rig tilted further forward, storm waves broke over her bow and began to fill the 80-foot-deep chambers in which the anchor chains were stored. This increased the list. There was no flood alarm in the lockers, so the crew may not have known what was happening.

The ballast pumps, located in the stern of the rig and now "uphill," were unable to keep up with the task, later studies revealed.

At 12:52 a.m. the radioman of the Ocean Ranger put out a mayday call, reporting a severe list and requesting immediate assistance. It was the first report of trouble.

Captain Duncan began steaming in, and at 1:09 a.m. the following message was heard:

We are the ODECO Ocean Ranger . . . and are experiencing a severe list of about 10-12 degrees and are in the middle of severe storm . . . . Request asst. ASAP. We are an offshore drilling platform. We will stand by as long as possible . . . .

It was about 1:30 that a voice out of the storm reported: "There will be no further radio communications from the Ocean Ranger. We are going to lifeboat stations . . . . "

At least 31 men managed to enter Lifeboat No. 2. To escape they had to strap in and begin their descent by supporting wires 100 feet down to the raging surface, into waves as high as five-story buildings. Descending through the blizzard into the first of the wave peaks, the lifeboat engine already running, they had to try to disconnect the boat from the lowering wires and flee, at the lifeboat's maximum speed of 6 knots, from the towering cliffs of water that threatened to smash boat and crew into the exposed structure of the rig.

Lifeboat No. 2 managed to rendezvous with Capt. Duncan's supply boat. But it had been mortally wounded and capsized while the would-be rescurers watched.

Fifty-one men were counted in the water that night. Those not in the lifeboat may have jumped, or fallen, into the sea. Some may have remained on board the listing rig, aware that to enter the freezing water without protection would be fatal. Some may have remained on the Ranger to the last and ridden with her through the arc of capsize at 3:05 a.m.

Of the captain, Clarence Hauss of Baltimore, nothing was heard that night. He made no radio calls.

The chief drilling superintendent or "toolpusher," Benjamin Kent Thompson of Mississippi, discussed the broken porthole in walkie-talkie conversations aboard the Ranger, which were overheard on radio on nearby rigs. But he never sent word of any problems to shore.

The only supervisor aboard the Ocean Ranger who reported the broken porthole was the on-board representative of Mobil Oil of Canada, Jack Jacobsen, the so-called "company man." He informed his shore base of the accident in mid-evening. It was Jacobsen who, at 1:09 a.m., called for Coast Guard assistance.

The "reason(s) for the almost total lack of communication from the rig concerning the listing problem is unknown," the Coast Guard concluded.

TOMORROW: The witness not called