: The ideal solution for a low stability 'yak might be a seat belt.
: One on the seat or maybe on each knee.
: I keep coming to the idea of a seat belt ratchet connected to each
: knee. A fast bracing move locks it-like a seat belt does with a
: sudden move. Instant bracing.

: Will

Knee straps work. I've paddled an older, quasi-whitewater Prijon sit-on-top, with straps that fit up and over the knees . . . and I could roll that boat with no other connection to it.

Of course there are many preferences, but hip padding is de rigueur in whitewater boats, and would help keep him in the boat. I don't use it in any of my builds, but I do slide around in them, a lot, depending on their size. The extra room is also useful for many maneuvers, though, as mentioned.