If Lake Washington ever freezes, I’m crossing it this way! Mark Harris says, I was lucky to take it out on a day with smoothly varying winds from 20-40mph (10-20m/s), and although slightly overpowered, I could cruise comfortably at 15mph (20kph), with bursts over 20mph (30kph). This top speed was definitely not limted by the sail, but by my survival instincts. In fact I didn’t dare reach or run, and limited myself to tacking about 20 degrees upwind to limited my speed, and skated home under my own power with the sail folded up like an umbrella. On smoother ice and with more experience I would expect to get up to 30mph.Link