Middle of a river? In current? Around a vertical log or over and under a sweeper? Other logs/debris there also? Consider that others as well as the owner did not try and retrieve it and why that may be.

I've done it quite some time ago where someone dumped at a single sweeper sticking out from a small mid river island. Over and under fold and the victim was stranded so two of us had to do something. Very very nervous as we had no lines and there was not much space below the sweeper and if either of us slipped under it would have been very dire. We seesawed the folded boat out to end of the sweeper into deeper water, but it seemed to take 20min or longer. One of those very uncomfortable things I/ve done that make it hard to sleep some nights.

I certainly don't know your situation, but if you don't know your way around current or have a safe place to work from - take a breath and go for a walk somewhere and enjoy the fresh air while you can.