Every year a whale hunt, sponsored by the Japanese government, kills over 400 minke whales off the coast of Antarctica in the Southern Ocean Whale Sanctuary.
The Japanese whaling fleet consists of one spotter ship, three catcher ships (very fast - with grenade tipped harpoons mounted on the front) and one factory ship.
This year Greenpeace activists disrupted the hunt using non-violent direct action.
The traditional Greenpeace tactic against whale hunting is to position a small fast boat between the harpooner and the whale. In this case, the activists only had enough boats to cover one or two of the catcher ships.
Instead, they focused on blocking the delivery of whales to the slower moving factory ship since a "catcher" could not return to hunting until it had delivered its catch.
Normally, the whalers would attach a cable to the whale and drag it through the water from the catcher ship and up the stern ramp of the factory ship. If this procedure could be stopped then so could the whaling.