It would seem relatively easy to tie speed to the direction the boat is facing. The more perpendicular you are to the 'wind direction' the faster you move. Or m

It would seem relatively easy to tie speed to the direction the boat is facing. The more perpendicular you are to the 'wind direction' the faster you move. Or make the fastest velocity 45 degrees from wind direction, for a bit more realism. Basic sailing physics can add to the fun.