This is a film by Dan Stone about the anti-whaling activities of the Sea Shepard Conservation Society, apparently filmed around 2008/9, on their voyage to the Antartic to disrupt the Japanese ‘scientific’ whaling run.
The Japanese and everybody else knows that there is nothing scientific in their whaling fleet, and that the whales are caught simply for food, in condradiction to the various treaties that have called for a moratorium on whaling.
The film follows two vessels as they try and find the whaling ships, which turns out to be no small task, as the Japanese have tracking equipment and can avoid contact with the soceity’s vessels.
When they do eventually run into one then they have various tactics for disabling it, like throwing stink-bombs on the whale landing platform, which will make any meat killed there smell foul. They also run drag nets across the ship and under its propellers in the hope of snagging them.
The voyage is difficult and dangerous, and requires no small amount of skill on behalf of the sailors, and it is surprising that at the end of the film we find many of the volunteers on the ship are complete non-professionals.