The biggest swells I’ve ever been kayaking through were large enough that my back started to hurt from the compression forces of going up the peaks after a couple of hours. Half the group of very experienced paddlers ended up puking and there’s nothing you can do but keep paddling. When the waves are big enough to fit an double person expedition kayak in the troughs and not have them touch the walls, you start to think maybe it’s a good time to find some earth under your feet instead.