DEAD-SERIOUS PRANK:

By JOHN SKOW/ABOARD S.V. MANUTEA

Nearing 1 a.m., Sunday, Sept. 3., just beyond the French navy's 12-mile exclusion zone at Mururoa, the South Pacific atoll where France plans to test nuclear bombs. Light wind. Half-moon. Waves from a far-off storm swell under La Rebaude, a broken-engined, radio-dead ketch owned by Greenpeace. The crew hands two black-painted sea kayaks over the rail. They are then tethered to a Zodiac inflatable boat already pitching in the water.

Al Baker, 31, a veteran Greenpeace activist, starts the Zodiac's 15-h.p. motor, and Matthew Whiting climbs aboard from the ketch. Whiting, 36, is lately of the French Foreign Legion; for that matter, he is lately also of the British army, the Spanish Foreign Legion and the University of Hertfordshire, where he studies literature. The two men, both British, carry green fatigues in waterproof bags. They have short haircuts. Whiting, burly, with a broken nose, speaks fluent rough-and-tumble French that he learned in the legion while serving on Mururoa. Baker, a lean, hard mountain climber with a seen-better, seen-worse expression, speaks nothing but rich, working-class Sussex. Someone says, "Cheers," Baker revs the outboard and the little inflatable, low in the water, rocks away on the swell, towing the kayaks toward Mururoa. The air is still, and for 10 minutes more the whine of the Zodiac's engine can be heard on La Rebaude. Then, nothing.

Beyond Mururoa's reef, a high seawall protects the atoll from natural storms and from tidal waves occasionally heaved up by the underground nuclear explosions. A second, lower seawall also surrounds the atoll. The single entrance to the lagoon within is only a few yards wider than the beam of a medium-size oceangoing ship. Protest vessels have been aiming at this breach since 1972, and last month the Greenpeace flagship Rainbow Warrior II, a successor to the Rainbow Warrior blown up by the French at Auckland, New Zealand, in 1985, was rammed by a French warship as it tried to enter the lagoon.

But Baker and Whiting are not headed for the entrance. They will abandon their Zodiac four or five miles out at sea and negotiate the reef with the kayaks. Reaching land, they will hide the kayaks and climb both seawalls with grappling hooks. With luck they will have a day or so for mischief before they are caught. The men plan to tag Mururoa's buildings with Greenpeace stickers and graffiti, slip notes to some of the press people invited by the French to witness the explosions, write a few postcards of Mururoa and drop them into the PX mail slot, get the French to search for them, and perhaps stall the first test. The stunt is planned as a classic Greenpeace "action," a dead-serious, nonviolent prank executed at considerable peril.

The plan is, if the two infiltrators are about to be captured at sea or on the beach, they will fire a parachute flare to signal their comrades on La Rebaude. There is no flare. The lights of a French patrol boat appear to the north, at the 12-mile limit. It motors to within 300 yds. of La Rebaude, showing its presence. Then it falls away.

A 42-ft. ketch, La Rebaude had sailed from Papeete, the capital of Tahiti, at midnight 11 days earlier, without clearance from the French, and rendezvoused with the two kayakers at sea a few miles down the island's coast. Greenpeace bought the boat somewhat casually at dockside in Papeete and equipped it in four days, without sea testing and without including a long-range radio transmitter or receiver. (The diesel engine died four hours into the voyage, so the vessel also lacked electric power, except a little generated by solar panels, and thus had no functioning refrigerator or electric bilge pump.) A tiny shortwave radio occasionally brought in a scrap of intelligence. Somebody had reached the quarter-finals at the U.S. Open. An Australian-rules football team had lost.

During the long night watches as they sailed to Mururoa, La Rebaude's hands told Greenpeace stories, many of which shared the same moral: "The military lies. Corporations lie. We don't lie." Twilly Cannon, from Missoula, Montana, the boat's captain, endured months in 1990 stalking the Soviet navy as it prepared to ditch another spent nuclear reactor in the Kara Sea northeast of Murmansk. Michelle Sheather, an Australian, was on the Rainbow Warrior when the French blew it up, and had left the ship 15 minutes before the limpet mines went off.

And Whiting told why he was bitter enough to risk his neck. He is convinced--without any real evidence--that the French used the Foreign Legion troops on Mururoa as nuclear guinea pigs. They were a labor force, reinforcing the island's coral with concrete and rebuilding roads that buckled after bomb tests. But the legionnaires worked in areas contaminated by radiation, Whiting insisted. Someone not French had to clean up debris after explosions. Blood and urine samples were taken weekly, but no results were revealed. He was beaten up, he said, for asking a single question about the effectiveness of Geiger counters.

A few hours after dropping off Whiting and Baker, La Rebaude reaches a flotilla of protest boats at a spot in the open blue ocean--139.05 degrees W, 22.30 degrees S--about 15 miles off Mururoa. One-masters and two-masters crowd the site; the Manutea, a Greenpeace boat carrying journalists, heaves into view. French picket boats motor slowly at the line of the exclusion zone. A French jet labeled MARINE mock-strafes the boats one by one, diving from about 1,000 ft. to not more than 150 ft., then rising and diving again. Military helicopters buzz about, low enough for the mustaches of the harnessed, helmeted commandos to be visible through the open cargo doors.

Tuesday morning brings two developments. One is that Whiting and Baker have been caught. They evaded the French for two days. That is a victory. A bit later, the news comes that the French have exploded their first bomb, a small one about the size of the one dropped on Hiroshima.

Dave McTaggart, 63, sailed his boat the Vega into the exclusion zone in 1972 and '73, and was almost beaten to death by the French. Now he's returned with the Vega. Yes, he says, Greenpeace will stay on at Mururoa. He answers the radiophone. "Look," he says to someone in Papeete, "I need to know exactly which of those parliamentarians is prepared to violate the zone. Yeah, yeah, call me tomorrow."