Good point on the canoe/kayak thread drift, and good photos at that link, Gargoyle--there are clearly some similar skill sets, and some different. Smaller closed craft versus larger open craft. But you don't see any photos of her rolling that canoe--because once is all it takes and she's out of the competition.

That's also a very useful diagram of the action of water as it goes over a dam. Avoidance is obviously the key--how many people would have the presence of mind to remember to dive to the bottom of the river to get spit out of that loop?

SRS