In the icy waters of the Southern Ocean Whale Sanctuary, a protest boat is rammed by Japanese whalers and sinks soon afterwards. But who was really to blame?

January 2010. In the freezing Antarctic waters of the Southern Ocean Whale Sanctuary, Sea Shepherd boat the Ady Gill is rammed by a Japanese whaling ship. The Ady Gill sinks soon after. But who was really to blame?

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https://youtu.be/ynecStOsoto

"I thought we'd be bringing people back in body bags."

Pete Bethune isn't a man to mince his words. Especially not when it comes to whaling in the southern ocean around Antarctica.

"It's the Wild West down there," he says bluntly.

He would know. Eight years ago, as the skipper of a high speed boat with a crew of environmental activists, he tested the limits of the law by getting up close and very personal with the Japanese whaling fleet.

On that occasion, his boat came off second best. But possibly the real damage done was to Pete Bethune's sense of the world, his respect for his fellow activists and maybe, to himself.

In 2008 Bethune set a new speed record for circumnavigating the globe in a bio-diesel fuelled trimaran named Earthrace, a vessel he called "the coolest boat in the world". Just after finishing his record-breaking journey, a journalist asked him what he wanted to do next.

"Just off the cuff I said I might take (Earthrace) to Antarctica to disrupt the Japanese whaling. (Afterwards) I got a call from Sea Shepherd."

"Six months later, there I was driving the boat down to Antarctica."

Founded by Captain Paul Watson, Sea Shepherd Conservation Society uses a mix of direct action tactics and sophisticated publicity campaigns to, in their words, 'conserve and protect ecosystems and species'. The Society is famous (or infamous) for opposing Japanese whaling programs in the Southern Ocean Whale Sanctuary surrounding Antarctica.

Since the sanctuary was established, it is estimated that more than 10,000 whales have been taken for what the Japanese call scientific research. The IWC rejects this description and so do Sea Shepherd. So does Pete Bethune.

From 2005 to 2017, the Sea Shepherd fleet, unofficially known as Neptune's Navy, disrupted the Japanese hunt by doing what Bethune calls 'naughty stuff.' This involved ramming their ships, attacking the crew with butyric acid and rancid butter and deploying prop-fouling cables.

"What we did down there was illegal. We're breaking the law. But we would also argue that they (the Japanese whalers) are breaking the law with what they do…

Go to this episode on rnz.co.nz for more details