Buying
a Sail
Eight questions
Getting a quotation
Building your sail
Click here to get to it. You can download a PDF measurement form.
- I: The height of the foretriangle measured from the headsail halyard raised as far as it will go to where the mast meets the deck. If your boat has a deckhouse, measure the height of the deck house at the mast and add that to your first measurement.
- J: The base of the foretriangle measured from the intersection of the headstay and the bow to the front of the mast.
- P: The maximum luff of the mainsail is measured from the main halyard raised as high as it will go to the top of the boom where it attaches to the mast.
- E: The maximum foot length of the main is measured along the boom between the bearing point of the outhaul when tightened as far out as it can go to the aft face of the mast.
With the I,J,P and E measurements, we can go to our computer pricing program and come up with prices.
There
is occasionally some confusion with respect to mainsail area. Most sailmakers,
including ourselves, compute mainsail area as if the sail were a right triangle
with three straight edges. With this method area equals the luff times the
foot divided by two. Most mainsails are, in fact, larger than that by reason
of the extra area at the leech, called roach, which falls outside the straight
line triangle. With out charging you more, we make the sail with the proper
amount for your boat.Racing sails are built to maximum allowable girths as defined by the rules, while cruising sailors prefer less roach so that the back edge of the sail does not hit the backstay each time you tack.
You'll notice that some of the jibs on price lists
include a percentage figure in their name and some do not. Examples are
"153% No. 1 Genoa" and "135% Passagemaker II." The percentage
figure is a measure of overlap, sometimes called an LP percentage. "LP"
is another term from the rating rules, like "I" and "J."
It is the acronym of Luff Perpendicular and designates the shortest, or
perpendicular distance from the clew to the luff of the sail.If the luff of the sail is considered to be the base of a triangle, then LP is the height, and the area is the base times the height divided by two. LP is expressed as a percentage of the base of the foretriangle, or J, and that is the percentage figure which appears in a price list. For example, if J is 10 feet, a 153% genoa will have an LP equal to 153% of 10, or 15.3 feet. This sail's area in square feet will equal ((1.53 x J) x luff length) divided by two.