The anti-whaling group, Sea Shepherd, is confident it has enough to time to reach one of its boats, which is in distress in the Southern Ocean off Western Australia.
The 35 metre Brigitte Bardot was chasing a Japanese whaling ship in six metre swells when a huge wave cracked its hull and damaged one of its pontoons.
The Sea Shepherd flagship, Steve Irwin, is racing through heavy seas to reach the damaged boat, which has 10 people onboard.
The captain of the Steve Irwin, Paul Watson, says the crack is getting wider, but the Brigitte Bardot's skipper is confident it will remain afloat until help arrives.
Mr Watson expects to reach the boat by Friday afternoon - and then tow it to Freemantle in Western Australia for repairs.
He says this is the first time in eight years anything like this has happened.
