Earlier quoted context omitted.
two other unneccessary details: 1. that 15m one was the most fun I've ever had on a wave, ever. Think of it like going down a ski slope in a canoe, except the ski slope moves with you for miles. 2. we had one of the motorized lead boats sink that year due to them. Interestingly, you're more safe in the canoes on them than you are a standard boat.
Wait a second. Do you actually keep "surfing" down it for miles?? I thought that was only done near shore where waves break. If so that's the most amazing thing I learned this year yet :-)
Surfing is just sliding down the rise in water caused by a wave at the pace as the water rises behind you as the wave moves (in the case of standing waves, I mean moves relative to the reference frame of the water).