It seems there are few causes left in the world that can prompt a man to voluntarily leave his family for life on the oceans with no pay.

But for the crew of Whales Forever , there is no cause more precious than the high seas war to save whales and other endangered marine life from commercial plunder.

Mr. Dave Jennings of the Shetland Islands said he didn't think much about his decision to leave his wife and two children to become a commando on a mission to bust up illegal whaling.

"It was my son that made me come,'' he said yesterday at Penno's Wharf, where the whale-festooned ship was berthed.

"He persuaded me. As for my wife, she's as committed as I am.'' Mr. Jenning's commitment, like that of the other 14 crew, is to fight illegal whaling and drift netting wherever it's occurring.

They and their ship are part of the Sea Shepherd Conservation Society, whose founder, Mr. Paul Watson, split from Greenpeace in the late 1970s to wage more aggressive campaigns against whalers.

But the Society's tactics -- from blockading, to cutting drift nets, to ramming ships -- has seen its members branded as environmental vigilantes, terrorists and pirates.

Certainly Whales Forever 's rigging leaves no doubt the ship is on something of a war-footing. Her mast lists the ship's sinkings -- nine of them -- much like Second World War fighter planes once listed kills.

Under the flags of victim nations, her mast boasts the sinking of two Norwegian, two Icelandic and two Spanish ships. A skull and crossbones is the flag for three "pirate whalers'' also sunk.

Mr. Axel Schoeller, Whales Forever 's first mate, said critics ignore his ship's mission which is simply to uphold the law.

"We are enforcing the environmental laws of the United Nations and the International Whaling Commission to save and protect marine wildlife worldwide,'' he said.

"We're not really at war. We're trying to enforce the law which is that whaling and drift netting are illegal worldwide. Nobody else is enforcing it.

So if in that there is any confrontation, it's no problem for me.

"The only way you can stop whaling these days is through direct action.'' Whales Forever got her nose bloody for the first time this summer when she tried to stop Norwegian whalers hunting minke whales just inside the Arctic Circle.

En route, she was intercepted by a Norwegian Navy frigate. Mr. Schoeller said frigate fired water bombs, jammed the ship's propellers with ropes which "messed up the engines'' and finally rammed her bow.

"They endangered our crew,'' he said. "We had to retreat to the Shetland Islands.'' Mr. Schoeller said Sea Shepherd's tactics to stop whaling and drift netting involve "cutting the nets and possibly ramming them if we're sure we're not endangering the crews.

"Our first priority is not to hurt people. We're just trying to enforce international law against whaling and drift netting.'' He described the converted oil rig supply ship, commissioned in 1970, as strong, very stable in bad weather and manoeuvrable.

Whales Forever , which is being repositioned via Key West to fight later this year in the Pacific, has all the markings of fanatical warrior.

A former crew member painted the ship from stem to stern with whales -- humpbacks, sperms, killers, minkes -- swimming along her blue hull and across her decks.

On the nose of her bow, she is armed with rows of stubby steel teeth which are used to cut drift nets. At the stern, she carries water cannon which the crew uses to "deter people from boarding us.'' Mr. Schoeller, an Austrian, said that whenever Sea Shepherd ships go into action they carry a lot of media people. "They're our insurance.'' Mr. Jennings, the ship's engineer, added: "We have to go out there and politically embarrass these countries about breaking the law.'' Mr. Schoeller, like many other crew members, said he was already sympathetic to the stresses on the ocean environment before he was recruited by Mr.

Watson.

"I've seen what's going on in the environment,'' the professional sailor and diver said.

"This is my chance to do something. What's going on is serious. It's not only whaling and drift netting but over-fishing and pollution. Sometimes things get to a point where they have to be stopped.

"We should try to preserve the resources we have.'' Third engineer Mr. Rory Bresnihan of Ireland boarded Whales Forever in June after speaking with Mr. Watson. He was already pretty angry about man's abuse of the environment -- the "ignorance'' of Asians using rhino horns for aphrodisiacs and the killing of tigers to make penis soup for good health.

"It's all a disgrace,'' he said.

While in Norway this summer, he came across Paul Watson.

"He's the only one whose really active,'' he said. "He's not radical.

He's just doing something.'' All of the crew are volunteers. They do not make any money from the Society.

Rather, all the money they take in is donated.

"If people can give us anything, we're glad to have it,'' Mr. Schoeller said.