"Shaun Baker plans to leap over waterfalls in his own invention – a jet kayak. And he even has his eyes set on Niagara, he tells Chris Mooney"
This article is interesting. It's about Shaun's jet powered kayak and how he wants to run some otherwise unrunable drops. A 330 cc jet engine gives quite the "boof stroke".
It also talk about how dangerous the boat is. He seems to get burned and shocked a lot more than the mentioned when he has been on TV.
Jet kayaking over the Niagara Falls - Times Online