Now, the Canadian-registered ship has been forced to rest.

Last month, it was detained on arrival in South Africa by marine officials who say it does not meet safety requirements.

The crew talks of a diplomatic conspiracy to shut their campaign down - and as they wait, they muse on their latest high-seas battle.

The 657-ton Farley Mowat - flying the skull-and-crossbones like a modern pirate ship - stalked Japanese ships hunting minke whales through the huge waves of the Southern Ocean and eventually sideswiped the fleet's cargo ship.

"Every time we approached them, they ran. We kept them running for 4,000 miles and 15 days," captain and activist Paul Watson told Reuters from the deck of his black steel ship.

"We couldn't catch them, so it was constantly a hit-and-ambush type of thing," he says, proudly recounting tales of the whalers he has helped to sink and the damage caused to those that escaped.

A founding member of Greenpeace, Watson now heads the Sea Shepherd Conservation Society, which broke away from Greenpeace and believes in action rather than protests.

The Farley Mowat, named after a Canadian author known as an environmental champion, is Sea Shepherd's standard-bearer.

"We don't injure anyone (but) we do damage property, property that has been used for illegal activity. We confiscate long-lines, we confiscate drift nets, we intercept poachers and we have sunk whaling ships."

MODERN-DAY PIRATE

Labelled a pirate and an ecological terrorist by critics, the grey-bearded Canadian says he is upholding international laws and scorns what he calls a "softer" approach adopted by groups like Greenpeace to end whale hunting.

"Nobody would walk by a kitten or a dog being kicked to death, nobody would walk by a child being abused or a woman being raped and beaten," he says.

"I don't see how anybody can stand there and watch when a whale is harpooned and dies an agonising death without intervening."

Watson and his small crew spent 50 days in the Southern Ocean, a whale sanctuary, gunning for the six-ship Japanese whaling fleet, panicking vessels 10 times as big as their own into hasty retreat. The Japanese fleet set out in November, aiming to catch 850 minke whales.

Japan abandoned commercial whaling in 1986, in line with an international moratorium but began catching whales again the following year for what it calls scientific research. Critics say the whale meat ends up in expensive restaurants.

Despite international disapproval, Japan announced plans last June to double its annual catch of minke whales to 850. It also has a quota of 10 fin whales, the second biggest member of the family after the blue whale.

Last month, after the clashes with the Farley Mowat and two Greenpeace ships in the Southern Ocean, an official at Japan's Fisheries Ministry said the confrontation would not halt Japan's whaling programme, but could reduce the size of the catch.

CONSPIRACY THEORIES

The activists on board the Farley Mowat, now languishing in a drab security zone in Cape Town's harbour within sight of the expensive Royal Cape Yacht Club, believe Japan has something to do with their detention.

"I know when I am being harassed. It seems to me that Japan is pulling some strings around here," said Watson.

He claims the Japanese government has pressured South Africa, using its economic clout - an accusation both Japan and South Africa vehemently deny.

"There is no pressure from Japan or Canada, there is nothing like that. It is just nonsense," says Saleem Modak, operations manager at the South African Marine Safety Authority (SAMSA).