Rake is how far the mast is swept backwards from vertical. As the wind increases you will need to rake the mast progressively more to keep the boat balanced.
You can measure rake a number of ways. One common way is by measuring the distance from the top of the mast to the keel band at the stern. SEE PHOTOS BELOW
Required Rake range using the above method is:
Fully Upright – 7850mm (7.85m) or 25ft 8in
Fully raked back – 7650mm (7.65m) or 25ft
Take the measurement from the underside of the contrasting band at the top of the mast to the keel band as shown.
You can generally do this by using the main halliard to pull a tape measure to the top of the mast or putting the rigged boat on its side.
The mast must be straight (no prebend) and without the sail to measure it properly.