Convinced that there is no reason that 90 degrees should be the optimum fin angle for starboard speed runs I built my first prototype. Waiting for wind.

It's canted 18 degrees. Under conditions where you may need 20kg of lateral lift, the fin will have to work a little harder and produce 21 kg of total lift. But there will be an associated 6 kg of vertical lift. That should be a win. 6 kg less work for the hull, and only 1 kg extra lift required of the fin. (Hard to believe, but check the sin and cos of 18 deg) And the fin is more efficient at producing lift - a double win.

So much for theory I'll let you know how it goes, I'm hoping it will feel pretty good on starboard and very sluggish on port. If I can't tell the difference .. I'll let you know anyway.