I think he is referring to the clock code trick using your watch.
To start with max drift is half of your total wind taken from the spot wind chart or any other source you can find. Then work out how much the wind is off your desired track. 10 degrees is 10 minutes on your watch which is 1/6 x-wind. 30 degrees is 1/2 x-wind and on until you hit 60-90 degrees where you take full x-wind in which case you apply your max drift to the track to work out your heading after taking into account variation. My CRP-5 is gradually gathering dust as we speak.