The high-speed anti-whaling vessel Brigitte Bardot will leave Fremantle for Antarctica this morning after limping back to port with engine trouble yesterday afternoon.
The ship originally left its dock at Rous Head yesterday morning but hit trouble during sea trials and had to return.
Last night engineers were working against the clock to fix the stricken vessel.
Sea trials this morning have proved the engine is sound and the vessel is ready to join a two month campaign against whaling in the Southern Ocean.
Manager of the Brigitte Bardot Simon Ager said he wanted to make sure the vessel was ship shape before venturing south to take part in what could be the final battle against Japanese whalers in Antarctic waters.
The boat will join two other protest ships in the Sea Shepherd fleet in a bid to prevent Japan from killing more than 900 whales.
Sea Shepherd hopes to find the seven-strong whaling fleet in an area of ocean the size of the United States by Christmas Day.
Sea Shepherd leader and captain of the organisation's flagship, the Steve Irwin, Paul Watson said the three vessels would search different areas of the Southern Ocean in a bid to find and intercept the Japanese fleet.
He said the fleet had been spotted near Lombok earlier this week and was currently thought to be heading down the West Australian coast.
"The Japanese fleet will take another five days to get to the Southern Ocean and we hope to head them off as soon as they get here," Captain Watson said yesterday.
He said he hoped this season would be the Sea Shepherd's last in the Antarctic and that it would put an end to any whaling in the southern hemisphere.
Last year the Japanese whaling fleet left Antarctic waters a month earlier than expected having killed less than 20 per cent of its quota citing harassment by Sea Shepherd as cause for its retreat.
This year the whaling fleet will be bolstered by two security vessels.
Five West Australians are among the international crew of 88 aboard the three Sea Shepherd vessels.