Unless you’re a professor of mathematics who can think in pure numbers, the easiest way to plot a course compensating for leeway is visually. Whack in the course you really want, then literally sketch the wind direction on the chart. It’s obvious now which way to steer ‘up’ so as to have the boat slide along the desired track. Plot a small line to indicate this, and that’s the course to hand up to the helm. As to how many degrees to apply, that’s another story. If in doubt, go for 7…