Anti-whaling protest ship in Southern Ocean distress

Japanese whaling fleet vessel Yushin Maru No. 3 sprays water cannons at Sea Shepherd activists in a dinghy boat during their clashes in the Southern Ocean February 4, 2011.

SYDNEY (Reuters) - Anti-whaling organization Sea Shepherd said one of its boats chasing the Japanese whaling fleet in the Southern Ocean had issued a distress call after its hull was cracked by a rogue wave.

Sea Shepherd flagship the Steve Irwin was fighting heavy seas to help rescue the damaged Brigitte Bardot chase boat and is expected to take 17 hours to reach it, Sea Shepherd founder Captain Paul Watson said Thursday.

"This is disappointing, but these are hostile seas and we have always been prepared for situations like this," said Watson via satellite telephone from the Steve Irwin.

"Right now the safety of my crew on the Brigitte Bardot is our priority and we intend to reach the crew and then do what we can to save our ship."

Watson said the damaged boat would be returned to Australia, while a third vessel continues to chase the Japanese fleet.

The "Brigitte Bardot," with a crew of 10 (three British, three American, one Australian, one Canadian, one Belgian and one South African), is about 1,500 miles southwest of the west Australian port of Fremantle.

The boat was pursuing the Japanese factory ship Nisshin Maru in six meter (20-foot) swells when the wave slammed into its port side, cracking the hull and severely damaging one of its pontoons, said Watson.

The crack has been widening as the seas pound the vessel, but Watson said he was confident it would stay afloat.

The Sea Shepherd Conservation Society is a hardline anti-whaling organization. It attempts to disrupt or stop the Japanese annual whale hunt in the Southern Ocean by using "direct action."

Watson has said this year would be the most dangerous campaign yet against the Japanese in a protest he dubbed "Operation Kamikaze."

Japan's whaling fleet left Shimonoseki Port this month to begin the research whaling season near the Antarctic, accompanied by a Japanese Fisheries Agency guard boat.

Last season, Japan cut short its hunt with less than a fifth of its quota in response to harassment by Sea Shepherd, which saw an activist boat -- The Ady Gil -- sunk in a collision with a Japanese ship.

An international moratorium on whaling has been in place since 1986, but Japan exploits a loophole allowing whaling for scientific purposes to justify its annual hunt.

Australia filed a complaint against Japan at the world court in The Hague to stop Southern Ocean scientific whaling. A decision is expected in 2013 or later.

(Reporting by Michael Perry)