Yesterday sailing my Beneteau 373 in about 10 kts real wind I experienced the following. On port tack, my 135 Genoa set very nicely, close hauled about 1 inch off the lower spreader with tell tales flying nice and straight. On starboard tack, with the sail set just the same as far as I could tell, I had consistent "chatter" from the leech, so much so that it was banging the spreader. The cars were in the same place on both sides, and at the distance recommended by Neil Pryde for the conditions. Any idea why I would have this problem on one side and not the other?
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Is your mast true?
My only thought... If your mast isn't true the starboard car might not really be the exact same distance from the mast head. Use a halyard to check and see if it reaches the exact same point on either car track?
My only thought... If your mast isn't true the starboard car might not really be the exact same distance from the mast head. Use a halyard to check and see if it reaches the exact same point on either car track?
Leech line,
If the major portion of the sail is shaped correctly, the leech line is loose. Tighten it until you get uniform sail shape. If you over tighten it, it will cup right at the edge of the leech. If it is loose, it will chatter when the rest of the sail is trimmed. If you are extremely close hauled in your trim, it could be the main sheet is not centered. If you have a furing sail, it could be the foam luff is shaped convex on one tack over the other. It could also be the UV cover was not sewn carefully to the sail and causes an extra leech. One on each side of the UV cover. Just some ideas to check out... r.w.landau
If the major portion of the sail is shaped correctly, the leech line is loose. Tighten it until you get uniform sail shape. If you over tighten it, it will cup right at the edge of the leech. If it is loose, it will chatter when the rest of the sail is trimmed. If you are extremely close hauled in your trim, it could be the main sheet is not centered. If you have a furing sail, it could be the foam luff is shaped convex on one tack over the other. It could also be the UV cover was not sewn carefully to the sail and causes an extra leech. One on each side of the UV cover. Just some ideas to check out... r.w.landau
rw
In fact, I did tighten the leech line and it is a bit cupped about 1/3rd of the way up the leech; but why does it chatter only on one side? All the telltales stream nicely on both sides. Steve, you raise a point I hadn't thought of, and i will check to see if the mast (deck stepped) is out of true.
In fact, I did tighten the leech line and it is a bit cupped about 1/3rd of the way up the leech; but why does it chatter only on one side? All the telltales stream nicely on both sides. Steve, you raise a point I hadn't thought of, and i will check to see if the mast (deck stepped) is out of true.
Inspect your sail...
I had genny that I bought online and the guy said it was blown out. It was not blown out. Someone had the seams restitched. While restitching they stitched into the leech line about half way up the sail. I cut out those few stiches so that the leech line would work the whole leech and I am sailing with that sail on my furler after adding luff tape and UV. Yes I know about UV being to tight because That is what I did to my sail while reworking it. I had to take the UV off the leech and install new material. Is your sail a furling sail? The UV would be the only reason I can think of for chatter on one side. r.w.landau
I had genny that I bought online and the guy said it was blown out. It was not blown out. Someone had the seams restitched. While restitching they stitched into the leech line about half way up the sail. I cut out those few stiches so that the leech line would work the whole leech and I am sailing with that sail on my furler after adding luff tape and UV. Yes I know about UV being to tight because That is what I did to my sail while reworking it. I had to take the UV off the leech and install new material. Is your sail a furling sail? The UV would be the only reason I can think of for chatter on one side. r.w.landau
roller furling
When I unfurl I try to ensure that the tack is locked along the centerline of the boat. Could it be that the tack is stuck on stbd side, when shifting to a port tack it may change the effective AOA.
When I unfurl I try to ensure that the tack is locked along the centerline of the boat. Could it be that the tack is stuck on stbd side, when shifting to a port tack it may change the effective AOA.
Lots of good info here
Regarding reasons your leech might flutter on one tack but not on the other. Here's yet another thought: It could be possible that your angle with the wind might not be exactly the same on both tacks. Boat headings, and wind directions, vary constantly no matter how diligent a helmsperson you are. That would suggest the need to fiddle with the location of the jib cars to see if you can reduce the flutter once you tack. Might be worth a try.
Regarding reasons your leech might flutter on one tack but not on the other. Here's yet another thought: It could be possible that your angle with the wind might not be exactly the same on both tacks. Boat headings, and wind directions, vary constantly no matter how diligent a helmsperson you are. That would suggest the need to fiddle with the location of the jib cars to see if you can reduce the flutter once you tack. Might be worth a try.
Thanks for the ideas
Thanks for all the good ideas here. I am tending to the belief that the UV protection on the leech unbalances the sail on the starboard tack - the double layer is to leeward on that side - and that the sheeting angle will need to be a little different.
Thanks for all the good ideas here. I am tending to the belief that the UV protection on the leech unbalances the sail on the starboard tack - the double layer is to leeward on that side - and that the sheeting angle will need to be a little different.
David, I am glad you stated it was a furling
Sail. That has narrowed my guess to question the installation of the UV material. The Leech of a foresail is hollow. This is so the leech does not chatter. Main sails are built out with big roaches. The battens support the leech so that it does not chatter. If the person that installed your UV material installed it in long strips, it can not contour to the hollow of the leech. This would change the character of the sail from one tack to the other. When I incorrectly installed my UV material I installed 8' strips.This caused that extra cupping mostly on one tack. On the other tack the material was loose and would fall off like an extra leech in the sail. When I corrected the UV I installed 3' strips to allow for the contour of the hollow leech. If the sail material was not stretched (the other mistake I made the first time around) while installing the UV, the inner stitch line could be to tight also acting like a permanent leech line. Good luck, finding the culprit r.w.landau
Sail. That has narrowed my guess to question the installation of the UV material. The Leech of a foresail is hollow. This is so the leech does not chatter. Main sails are built out with big roaches. The battens support the leech so that it does not chatter. If the person that installed your UV material installed it in long strips, it can not contour to the hollow of the leech. This would change the character of the sail from one tack to the other. When I incorrectly installed my UV material I installed 8' strips.This caused that extra cupping mostly on one tack. On the other tack the material was loose and would fall off like an extra leech in the sail. When I corrected the UV I installed 3' strips to allow for the contour of the hollow leech. If the sail material was not stretched (the other mistake I made the first time around) while installing the UV, the inner stitch line could be to tight also acting like a permanent leech line. Good luck, finding the culprit r.w.landau
This might be obvious, but...
Are you sure the main was trimmed the same on both tacks? If the traveler was off-center, was it off the same amount both ways? If not, that would of course change the slot and give you different flows on different tacks. I think r.w. implied this when he talked of the mainsheet being "centered".
Are you sure the main was trimmed the same on both tacks? If the traveler was off-center, was it off the same amount both ways? If not, that would of course change the slot and give you different flows on different tacks. I think r.w. implied this when he talked of the mainsheet being "centered".
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