Measuring for sails

Rig & Boat Measurements

These measurements can be found on your sail plan or in our data base covering thousands of boats. Sounds easy but in real life there are any number of reasons that the actual size of your rig could be different from the factory specs. Masts and booms are broken and replaced manufacturers changed the rig as model aged etc. The only way to be sure of rig dimensions is to check them yourself.

Headsails

Three measurements are needed for the headsails. " I " is from masthead to deck level. Pull a tape measure or spare line up as far as it will go using your jib halyard and measure down the deck level. On boats with a cabin top above the deck this may take a little guesswork, just get close. "J" is base of the for triangle. Measure from where the headstay meets the deck back to the forward edge of the mast. "J" is used in calculating the % of overlap for genoas i.e. 110%, 155% etc. "maximum luff" for hank on sails is the measurement from the mast head to the point you want to attach the tack of the sail. For furling sails attach the tape to the upper furling swivel, hoist it up until it stops, and note the measurement to tack swivel on your furling drum. This gives the maximum luff for a furling genoa.

Mainsails and Mizzens

Three rig measurements are needed to select or build a main for your boat. "P" is from the masthead to the top of the boom in it's lowest potion. "E" is from the back edge of the mast to out haul pin in it's furthest aft position. "LEECH" is from the masthead back and down to the out haul pin. (P2, E2 and LEECH2 are used for mizzen measurements) If you are racing and have black bands on your masthead, note the measurement down to the boom, then swing your tape back to the out haul and note the leech measurement. Remember to place the boom so it will clear your bimini top, boom gallows, head or ? before measuring. You will also need to determine tack setback, out haul pin height, size, and type of hardware. Please check drawings below.

Spinnakers and Storm Sails

With the basic measurements above you can also size spinnakers and storm sails. Symmetrical or racing spinnakers are usually built to 180% of the fore triangle area, cruising spinnackers to 165% plus or minus. If you are unsure about sizing these sails call me for more information.

The above instructions are very basic and certainly don't apply to every boat. Please call if you have any questions.

Selecting Sails From Our Inventory

Most sails, other than spinnakers, are defined by three measurements, luff(leading edge), leech (trailing edge) and foot (lower edge). Again, the rig measurements above will tell us the maximun dimensions for sails that will fit your boat. Sail dimensions in my inventory are listed in feet and inces, fully stretched as the sail would be on the boat.

Mainsails & Mizzens

Sails that are a little short on the luff or foot will work and sometines a small compromise can save money without hurting performance much. Using our in house re-cutting service it is often possible to shorten a sail economically. If you want to know if a particular sail can be cut down and what the cost would be please call. Minor modifications such as adding one or two full battens or reef points make sense.

Headsails

Once we have the max luff for a head sail we need to decide on an LP. Luff perpendicular (or longest perpendicular) is a line from the clew drawn to meet the luff at 90 degrees. This divides the sail into two right triangles so we can figure the square footage. A sails LP is compared to the boats " J " dimension to derermine overlap %. For example (if your boats "j" is 14 feet and you want a 150% genoa multiply 14 x 1.50 and we come up with an LP of 21 feet. Sails of less than 100% are jibs, those over 100% are genoas. Basically we compare the area of the foretriangle(I x J divided by 2) to the area of a sail luff x LP divided by two to find % overlap.

Converting a hank on headsail to roller furling is expensive and rarely makes sense unless the sail is in very good or better condition. Other changes such as adding hanks to a tape luff sail or shortening the luff often can be done economically.

Spinnakers

As long as the luff or luffs of a spinnaker are equal o or less than your " I " measurement and the foot is around 180% of "J" you can use it on your boat.

Assymetrical or cruising spinnakers are often less, 160 or 165%. Recutting a symmetrical spinnaker to an asymetrical or cruising chute is a fairly inexpensive modification.

Contacts

Loft hours: 10:00 am - 5:30 pm EST
Otherwise by Appointment

E-mail problems: I answer all emails within 24 hours. However, I also use a very tough firewall and have had a few problems with emails not getting through to me. If you don't get a response to an email sent to me, please assume I didn't receive it and call me at 1-800-507-0119. Thank you!