I was confused by Peter’s statement until I thought about a Great Lakes wave carrying a big hunk of debris coming my way. I’d go into warp speed to get out of the way, but if that didn’t work, rather my hull take the hit than my head. Never having experienced such an event, I’m not sure if that would be the right thing to do but it looks reasonable on paper…
We are talking about two different things. I was talking about a breaking wave heading for shore which catches your kayak and pushes you towards a rock or other obstruction. In that case, you brace into the wave to stay upright, and try to get over the top of the wave before it heaves you into the rock. If you don’t manage to get over the top of the wave, the bottom or side of your kayak will hit the rock. You were talking about a breaking wave heading towards shore which catches a chunk of debris and pushes it towards you. In that case, you try to get out of the way of the debris, and then brace into the breaking wave. If you lean away from the breaking wave and the debris, the breaking wave will certainly flip you.
pmmpete is correct. This is talking about a wave taking you toward an object, not taking an object toward you.
Not a white water expert here, so could be wrong. But to me the main difference is a wave’s energy is for a finite time, where a river’s energy is continuous. So you brace into the wave (leaning away from obstacle) to support yourself, which only needs to be done for as long as the wave is moving water. Once you hit the rock, you will stop and wave will flow past you. No more flow and you are left upright upright and paddle away.
A river flow is continuous, so bracing into the river flow (butt toward rock) would mean continuously bracing to stay upright. The water flow never stops.
Also some part of this in that most river rocks I’ve seen are worn smooth (mentioned this before, and had my butt handed to me - so understand that this is not always the case) and most ocean rocks are covered with sharp critters like barnacles and muscles, which would be painful to hit. Let the boat take the hit, not your body. One reason we prefer plastic boats over composite.
Side note - the Greenland skill called “walrus pull” is similar to a leaning into the river flow situation. Historically it was based around a hunter harpooning a sea mammal and then being pulled sideways by it, so the hunter needs to stay upright. You stopped against a rock sideways with water flowing past you and water stopped but you being pulled past water - these are the same effect. Walrus pull, though, is a case where you lean into the continuous flow (unlike white water) and is supposed to be quite hard to master.