If your drift boat flips, job one is to get everyone to shore safely. In a situation like this, there is typically no time to don a life jacket - the bad stuff happens before you know it. Also, many of the deaths that happen in flipping situations are caused by being pinned by the boat or caught in the log jam that caused the flip. In these circumstances, the life jacket is irrelevant. Earlier this month, a young fellow was killed because his boat was flipped going over a diversion dam, and he got caught in the backwash behind the dam. Wasn't pinned, but was held down by the water past his expiration date.
So what to do? The most common cause of sinking a drift boat that I am aware of is having your anchor release trip while going through a rapid, and then having the rope catch. If the boat is moving fast through the rapid, and the anchor goes down, and the rope snags (because you have a knot in the end, say) the boat will disappear from underneath you faster than you can [Bleeeeep!] you pants. Needless to say, there is no knot in the end of my anchor rope.
A related cause is trying to anchor in water that is too fast. Just because you CAN anchor in a spot, does not mean that you should.
Other common causes of issues are getting pushed up against the side of rocks and log jams. Avoiding these issues is a matter of rowing skill and caution. Also be very cautious about sweepers, which are trees that have fallen into the river. These can be nasty, as they're usually on the fast side of the current.
As to how to recover a boat, there is apparently quite a cottage industry on the Deschutes around recovering boats and rafts that have gotten highsided and pinned on rocks. They use swimmers, rope, block and tackle, and occasionally a wrecker to get the boats unpinned. Better to avoid the problem.
If you use the big head rather than the little head to do your thinking while you navigate a river, this won't be a problem. Best to avoid the more dramtic rivers, such as the Deschutes, and the Soleduc, until you get confident with your skills. If you're not sure how to get around a spot, get to shore and walk or rope your boat around the nasty spot.
An good book on this topic is River Rescue, by Les Bechdel and Slim Ray.
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