By Gordon Bell

The chained Farley Mowat floats under police guard in Cape Town harbour, out of reach of the whaling ships its captain seeks to destroy.

For seven weeks, the crew of the tiny activist ship harassed Japanese whalers in Antarctic waters, chasing the hunters through thousands of kilometres of icy seas.

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 talk 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 - 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 (6 440km) and 15 days," captain and activist Paul Watson said from the deck of his ship.

"We couldn't catch them, so it was constantly a hit-and-ambush type of thing," he says, 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.

"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."

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.

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.

He claims the Japanese government has pressured SA, using its economic clout - an accusation both Japan and SA 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.

"Do you think we would allow a ship of that size to come into our port without having the right certificates?"

Watson has vowed authorities will not stop his campaign, and has promised to intensify the battle against the whalers. "We will be back next year with a faster ship," he said.