Long after dark, Peter Willcox scans the calm South Pacific from the deck of the Rainbow Warrior. The glint of a headlight shines off his thick wire-rimmed glasses as a motorboat buzzes up and divers climb aboard the converted trawler to deliver their cargo—a young dolphin, drowned by the 15-to 30-mile-long driftnets hung by Japanese and Taiwanese tuna-fishing boats lurking nearby. "I don't like to run on anger," says Willcox, 37. "But this does make me angry. It's complete, senseless strip-mining of the sea. There's just no place for driftnetters, and we're going to make it as hard as we can for those guys to fish."

Those who know Willcox understand that this is no idle threat—that in defense of the ocean and its creatures he is willing to do whatever is necessary, even if that means breaking the law or risking his safety. His very presence in the South Pacific, at the helm of a new Rainbow Warrior, is a statement of unshakable purpose. It is the first time Willcox has been back in the South Seas since 1985, when he lost the first Rainbow Warrior—and nearly his life. That summer, Willcox and his crew were docked in Auckland, New Zealand, before heading out to document the effects of French nuclear testing on Polynesia's Mururoa atoll. To deter them, the French secret service planted two bombs on the Warrior, which detonated around midnight on July 10. Willcox, who had been sleeping, stumbled naked and without his glasses through the foundering Greenpeace vessel to guide 11 shipmates to safety, but photographer Fernando Pereira was killed trying to save his equipment.

"When a crew mate dies," says Willcox slowly, with biting understatement, "it's the worst possible scenario." He didn't just get angry, he got even. First he sailed to Mururoa on another Greenpeace ship to complete the planned protest, then he helped supply the evidence that eventually forced the French government to pay Greenpeace $8.1 million in reparations. Last year Willcox supervised the renovation and launching of a new Rainbow Warrior. "The bombing gave us a feeling of resolve," says Willcox. "If we're having such an impact on a big government, we must be on the right track."

Or the right wave. Without resorting to guns, bombs or violence, Greenpeace has been a tireless and effective pain in the afterdeck to those who pollute the ocean or destroy marine life. Since the first Rainbow Warrior was launched in 1978, the Greenpeace fleet has grown to seven ships, which patrol the world's waters from the Mediterranean to the South Pacific. The organization boasts nearly 4 million members worldwide, with offices in 22 countries. "These people are the last real heroes," says Daryl Hannah, one of many celebrities who are among Greenpeace's ardent supporters.

In his eight years with Greenpeace, Willcox has been arrested five times by five different countries. Though charges have always been dropped, he has spent a few nights in jail, most recently in 1988 after he and a Greenpeace contingent attempted to stop a U.S. frigate bearing nuclear arms from docking in Denmark. The Greenpeacers jumped from a small boat in front of the warship. "We were hoping that he'd slow down so there would be no danger of being drawn into the propellers," says Willcox. "But he just kept it at full speed, missing us by one or two feet." Fortunately no one was hurt. Says Willcox of this close call: "I can balance the personal risk against the risk of allowing nuclear weapons on ships. There are about seven reactors on the ocean floor now that will create pollution for thousands of years."

Willcox and other Greenpeacers were also arrested in 1982 for occupying a whaling ship at port in Peru, and the ship, while monitoring Russian whaling practices off Siberia, barely escaped apprehension by Soviet authorities. Then, two months before the Auckland blast, Willcox's Rainbow Warrior crew came to the aid of Marshall Islanders who had asked the U.S. government to relocate them because their atoll had been contaminated by nuclear tests in the '50s. When the U.S. ignored the claim, the Greenpeacers moved the islanders to a nearby atoll, and the ensuing publicity forced the government to admit its culpability.

Born in Norwalk, Conn., Willcox got his sea legs before he could walk. "When he was 6 months old, I tied his crib to the cockpit of a 36-foot sloop," says his father, Roger, 69, a city planner and an avid sailor. At 15, Willcox joined his father on a 40-foot yawl that won a race from Bermuda to Norfolk, Va., and six years later he was named the boat's captain. After dropping out of Antioch College in 1972, he drew No. 1 in the 1973 draft lottery. Encouraged by his mother, Elsie, a science teacher, he declared himself a pacifist and took a government-approved conscientious objector's job as first mate of the sloop Clearwater, an environmental advocacy boat on the Hudson River. He kept at it even when the draft was canceled. "Once I found a way that I could be politically active and enjoy it," says Willcox, the boat's captain from 1976 to 1980, "I stayed with it."

After nine months on a square-rigger doing whale research, Willcox signed on as skipper of the Rainbow Warrior in 1981. Following the bombing, he worked on other Greenpeace vessels before his new ship was launched last July in Hamburg. Predictably, Willcox's arrival in the South Pacific has not made everyone happy. Alan Macnow, a consultant to the Japan Fisheries Association, calls the Greenpeace allegations of indiscriminate fish kills "a lot of propaganda. Driftnets have a mesh size which is chosen to catch a specific species. Anything larger won't get caught." Willcox disputes this. "Driftnets take up everything that swims in the ocean," he says. "We have found swordfish, marlins, a whale and dolphins." Though an international treaty already bans driftnetting in coastal waters in the South Pacific, Greenpeace hopes its protests will prompt the United Nations to extend this protection to the open ocean as well.

Most days Willcox, who is paid $20,000 a year, spends eight hours on watch and a few more helping his 12-to 16-member crew run the Warrior's state-of-the-art communications equipment. During his free time, he may relax with a novel by his favorite science fiction writer, Anna McCaffrey. For the past few months, he has been involved in a romance with Liliana Trumper, 33, a former Rainbow Warrior doctor. "I'm not real great about keeping relationships going, because I move around so much," he says. "But I hope this one will last."

Though he has been banned from French Polynesia and risks six months in prison if he returns, Willcox still thinks about resuming the protest against ongoing nuclear testing there. "It's great to continue the work that was interrupted by the bombing," Willcox says. "I know we can make a difference. We've got to protect the Pacific before it's too late."