Here’s one that was totally new to me.
I have never seen this before, am not an expert canoer but i have a feeling i am not the first.
Kettle River, MN on a class 3 rapids, cascading layers of bedrock with about 6" to a foot of water, we flipped the canoe upside down and held on as we went down the cascade. About two thirds down the cascade, the canoe stopped on a shelf of rock, upside down, full of water, sideways with the water rushing against & around but not over the canoe. It must have weighed >1000 lbs full of water. We could not get it up high enough to get air under the edge. Every time we were able to lift it on the downstream side a couple of inches, it would move downstream, trapped my hands once (injured) and my feet once (injured). We cracked a paddle trying to lever it with both paddles.
Miles from civilization, it was a fix. It was like taking an IQ test that i was not smart enough to pass. I have never seen water lock a canoe down, upside down, immovable.
Our final successful attempt was to jam a large but liftable flat rock under it and kind of use it as a lever. I think we were really lucky.
Have more experienced canoers see this before?
Is there a recommended approach to the problem from freeing the canoe?