If you read the article, it's impressive how much time and effort it took to get it right. Every time they sunk it (like 40 times), the mechanic had to spend 5 hours rebuilding. And I thought cleaning up after a ride in a little mud was bad
Apparently on that last wave where he emerged from the wave, he crashed. There is mention of having to regear for optimal traction on the ocean

The article went on to say that his 4th gear was optimal and that shifting to 5th caused a loss of forward momentum. While the video makes it seem like he rode from the jungle to the wave, they actually had to build special barges to launch and catch the bike out on the waves. Pretty cool stuff.