Assuming you can easily climb up on your boom, the length Mast Mate you need is the distance from your mast head to your boom, the “P” measurement of your main. Go to the sailboat specs database and check the P specification. If not listed, the easiest way to make this
measurement is to attach a light line to your main halyard, hoist it to the top, put a piece of tape on the line at the boom, or further down. if you need a step or two below the boom, lower the halyard and measure the line. It is OK if a standard length Mast Mate, 27ft, 35ft, 42ft, 50ft, is a bit too long, the excess just lays on deck.
