The key is to move up and down with them. If you are stationary, then you are looking at things like 5 meter high waves with a 10 second period. So you go up fo

The key is to move up and down with them. If you are stationary, then you are looking at things like 5 meter high waves with a 10 second period. So you go up for 5 seconds then down for 5 seconds. You get used to it. For sailors, they tend to be going more or less downwind which makes the period longer for a given wave height. Assuming they aren't going straight down wind, their sail also forms a sort of feedback system which keeps them heeled over at a fairly constant angle so there isn't a lot of boat rocking going on. You can see typical values at http://www.stormsurf.com/page2/papers/seatable.html http://www.stormsurf.com/page2/papers/seatable.html Note that is in "feet@seconds" and the blue values are typical, the white cells wander off into computational fantasy.