Measuring for a Headsail

1. Height of I - If you do not have a sailplan and would like to know your I dimension, attach a tape measure to your Genoa halyard and hoist the halyard to the top of the mast. Be sure to attach a retrieval line so that you do not have to rely on the tape for pulling the halyard back down again. Now measure to the base of the mast for your I dimension. This is an estimated I dimension. The lower point of I is relative to the height of your freeboard and some other factors, but for a sailmaker's purpose this is sufficient.

2. Max luff length - With the tape still at the top of the mast at a full-hoist position, measure to the bearing surface of the tack attachment of the sail. This dimension is for a sail that is going to be attached with hanks. If there is going to be a furling unit on the stay, attach the tape measure to the masthead swivel, hoist it as high up the forestay as it can go, and measure to the bearing surface of the shackle on the furling drum.

3. Drum height - This measurement lets the sailmaker know how high the furling drum is off the deck so that he can calculate where the sail will sheet to be sure that it hits the track on the deck. Measure from the bearing surface of the tack shackle to the center of the forestay pin. Measure in stages: first to the top of the drum, then the height of the drum, and finally to the forestay pin.

4. Height of Forestay Pin - Include the height of the forestay pin by measuring from the center of the forestay pin to the deck.

5. Furling Swivel - Note that if you have provided the max luff length and drum height, this dimension will not be absolutely necessary, but it's always important to give your sailmaker as much information as possible. Measure from the bearing surface of the halyard attachment to the bearing surface of the sail attachment.

MEASURING TIPS. CHOOSE A CALM DAY IF POSSIBLE. STRETCH YOUR TAPE MEASURE AS TIGHT AS YOU CAN AND TAKE THE MEASUREMENT. IF NECESSARY MEASURE A FEW TIMES AND SEND US THE AVERAGE. DO NOT ALLOW FOR STRETCH, WE'LL DO THAT

O I DIMENSION © J DIMENSION

measure from the intersection of the forestay and the mast down to the deck___

measure from the forestay attachment point at the deck to the front of the mast

© MAX LUFF (no furling) measure from the halyard attachment to the bearing surface of the tack attachment (for hanks)____________________________

© MAX LUFF (for furling) measure from the bearing surface of the swivel shackle, to the bearing surface of the drum shackle_________________________________

© DRUM HEIGHT

© FORESTAY PIN

Q FURLING SWIVEL

© TACK SETBACK

© FEEDER HEIGHT

© LUFF TAPE SIZE

CD CLEW HEIGHT

© TRACK POSITION

© TRACK POSITION

© TRACK LENGTH

© TRACK POSITION MISC DETAILS

measure from the bearing surface of the shackle to the center of the forestay pin measure from the center of the forestay pin to the deck_______________

measure from the bearing surface of the halyard attachment to the bearing surface of the sail attachment----------------------------------

measure from the back side of the foil to the bearing surface of the tack shackle________

measure from the headsail tack attachment point to the bottom of the feeder_________

what kind of furling unit do you have, or do you have hanks?__________________

what is your preferred clew height (low at lifeline height, or higher near boom height?)----

measure from the forestay attachment point at the deck to the front of the Genoa track---

measure from the swivel shackle (or halyard for hank-on) to the front of the Genoa track- -

measure the length of your track----------------------------------

measure from the centerline of the boat to the track-----------------------

what color sunshield do you want? Which side of the sail do you want it on? * pass the tape around the outside of the shrouds as the leech of the sail would.

6. Tack set-back - Measure the tack set-back from the aft side of the foil to the bearing surface of the tack swivel. This ensures that there will not be any hard spots up the luff of the sail.

7. Feeder heigh - Measure from the bearing surface of the shackle on the furling drum to the bottom of the feeder.

8. Track position (fore and aft) - Measure from the forestay attachment point at the deck, to the front of the Genoa track.

9. Track position (athwartships) - Measure from the centerline of the boat to the track. If the track does not run parallel to the centerline, provide a measurement from the centerline to the front of the track and one from the centerline to the back of the track.

10. Track length - Measure the length of the Genoa track.

11. Spreader details - Use the same techniques described in "mainsail measurements" to get height, length, and angle of the spreaders.

12. Track position relative to the hoist (optional) - Measure from the maximum hoist point to both the forward and aft ends of the track. If you are measuring for a blade jib do not take the rig into account. For a Genoa, pass the tape around the outside of the shrouds as if it were the leech of the sail. Modern sail design programs allow the sail designer to enter data about the spreaders and design the sail taking them into account, but providing this dimension is one more cross-reference point for the sailmaker.

13. Height of stanchions - Measure from the base of the stanchion to the top. This is useful for the sailmaker to know when it comes to placing the height of the clew. If the sail will be barber-hauled out to the rail, the height of the clew should clear the lifelines.

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Responses

  • Laura
    How to meseaure headsail on sailboat?
    2 years ago
  • samlad
    How to measure headsail on sailboat?
    2 years ago
  • Delfina
    How to measure head sail furler?
    1 year ago
  • Petra
    How to find headsail angle?
    10 months ago
  • SABINE
    How is furler length measured?
    4 months ago

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