Buck,

I'm a bit late to this thread, but I'll add my recommendation against using your float tube, even U-boat style, in a steelhead or salmon river. In the 1970s, Jim Teeny and his father, both very accomplished anglers, were using their float tubes to cross the Sandy River in Oregon. Jim's father drowned. Of course, boaters in jet sleds, drift boats, white water rafts, canoes, and kayaks have had fatal accidents in rivers, too. Yet, there must be something to this, as float-tubing rivers would probably already be quite popular if people felt it was generally safe. I think the key limitation of the float tube in a river setting is the very limited control and manouverability relative to the speed of the current, varying depth, and abundance of unseen snags that can catch either you or your tube.

I use a jet boat, a canoe, and a small raft on rivers, and I try always to use them in environments where my ability to control my craft exceeds the control the river will exert on me. I don't use my float tube in rivers because I think the equation tilts toward the river exerted more control than I can.

Sincerely,

Salmo g.