Pete Bethune, skipper of round-the-world trimaran Ady Gil, has successfully boarded the Japanese ship which collided with and sank his boat to attempt a citizen's arrest on its captain.

Bethune, pictured here during an interview with Motor Boats Monthly, was on board his boat, formerly known as Earthrace, when it was struck by the Japanese vessel Shonan Maru No 2 in January.

Ady Gil was left with a large section of its nose missing following the collision, and later sank.



Bethune managed to climb on board the Japanese ship under the cover of darkness at 0629 (Perth time). He was taken to the side of the whaling ship on a personal watercraft driven by Briton Larry Routledge.

"The Jet Ski lay in wait for the Shonan Maru No 2 to approach. With the Japanese vessel making 14 knots through the water, Routledge manoeuvred the Jet Ski into position under the anti-boarding spikes along the port side of the Shonan Maru No 2," the Sea Shepherd Conservation Society said in a statement.

"Captain Bethune made the jump and climbed on board the whaling ship without being noticed."

Bethune plans to present the Japanese captain with a bill of $3m - the cost of replacing Ady Gil - and demand that he surrender himself to Sea Shepherd or take his ship to the nearest Australian or New Zealand port to turn himself in for the attempted murder of the six crew on board Ady Gil at the time of the collision.

Sea Shepherd added that it believed the Japanese ship would hold Bethune as a captive.

"This was an impossible mission," said Sea Shepherd's Paul Watson.

"Captain Bethune boarded a Japanese whaling fleet security ship at high speed in total darkness, breached the spikes and anti-boarding nets and is presently on board. He is there to demand justice for the sinking of his ship."