New mainsail shape advice

tsekul

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Hi There,
I have recently invested in a new main sail, I have to say I’m not that happy with the shape, but it could be me . I’ve played around with the tension on the batons, I just cannot get rid of the wrinkle on the top baton, where it goes into the box at the luff. The only way I can get the shape I think it should be is with loads of back stay tension. Is it me or is there an issue. Any advice greatly appreciated. I have enclosed two photos one with a fairly taut halyard and one with it very loose.
these things are a lot of money and need to be right. Thanks in advanceA61AA951-C275-4F37-9591-5909A10B394B.jpegC6B7D95A-7EFB-4607-A08A-7D3BD6605700.jpegA61AA951-C275-4F37-9591-5909A10B394B.jpegC6B7D95A-7EFB-4607-A08A-7D3BD6605700.jpeg
 

wilkinsonsails

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First pic shows you need to wind up the batten tension .Either slide stud rotat ion or a screw in the box ?
last pic looks nearly correct .
 

Birdseye

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looks to me as if the mast bend is not right. the luff is cut by the sailmaker on the accumption of a certain level of mast bend. Yours looks to be straight around the first spreader and curved too much around the second, pehaps the result of winding on too muct backstay. Talk to the sailmaker. Run a line uo the mast and measure bend as best you can. Really difficult to make any sense of just two photos but it certainly doesnt look right.
 

Bullsails

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If shot is in no wind, it is under no load.
when sailing with everything sheeted on and some mast bend it may be fine.
if it still has the knuckle in front and doesn’t blade out, you have two choices, tweak your rig for more sailing bend. Or return it to sailmaker to have a luff recut If that is not possible.
Give him a shot of sail fully set in about 15 knots to work with.
Sailmaker of 40 years!
 

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tsekul

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My main issue, excuse the pun is that the draft is way to far forward on the top 1/3 of the sail with no way of flattening it or moving it back unless I attach the baby stay and bent the mast. This would make tacking a real pain.

Not really what I was expecting, I thought it would set in a neutral position with the draft about 40% back. Then when I apply halyard tension or cunningham I could pull the draft forward to what is pictured.

Maybe I'm wrong and this is what it should look like .
 

michael_w

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How much kicker have you wound on? The leech looks pretty closed even on the photo with a tight backstay. Also the maximum depth of chord looks to be a bit too far forward.
 

tsekul

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I've tried with kicker and without, without I get a big wrinkle from the tack up through the sail. The foot and the leech I can mess with.
As the wind builds the draft naturally moves back but in light winds when I try and point as high as possible the angle of attack doesn't seem right. I've contacted the sailmaker but not had a response yet.

winding on the tension on the top baton has got rid of the wrinkle in the image, Im going to try tensioning the other batons to see what happens.
 

Bullsails

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Good info.
if you can’t bend the mast to accommodate the extra cloth in luff. Then it should be recut.
the issue is the sail/mast marriage. Just needs a tweak.
not a batten issue.
 

Birdseye

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Presumably Mr Bullsails, you cut the sail to match an evenly distributed amount of pre bend. I understand this is usually sowething like harf the mast extrusion chord - something in the 3 to 4 inches for the OP. But it looks to me from his photos as if his rig is set up with far more pre bend above the first spreader than below. . Makes some sort of sense if he isnt using the baby stay the rig was designed with

I used to club race a Moody 336 with twin spreaders and I had just the pre bend problem I describe. I was surprised how big a difference it made to get the rig set up correctly - and how long it took me to do that.
 
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tsekul

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Spoke with the sailmaker today, someone is coming out and checking everything. They basically say as has been discussed above, may be a case of tweaking the mast prebend ,but if that is not the case then they will do whatever it takes.
Thanks for all the advice and opinions.
if I remember I’ll post an after photo .
T
 

wagonicfolding

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It appears the halyard is short of full hoist. When hoisting ensure both the mainsheet and Vang are eased. Once hoisted remove or ease the topping lift. If you need additional luff tension with the sail fully hoisted use the Cunningham. The outhaul will help flatten the lower third. It also appears you have no battens. Installing those will straighten the leach of the sail.
 

Bobc

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Looks to me like your maximum draft is way too far forward. I assume you have a ton of haliyard tension on.

This might also be creating the vertical crease.
 

Birdseye

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Spoke with the sailmaker today, someone is coming out and checking everything. They basically say as has been discussed above, may be a case of tweaking the mast prebend ,but if that is not the case then they will do whatever it takes.
Thanks for all the advice and opinions.
if I remember I’ll post an after photo .
T
So what was the verdcit?
 

tsekul

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Funnily enough, spent the day with them today. They made some adjustments to the pre mast bend. Sailing ,tweaking ,sailing. Looks like a different sail.

Mast was too straight in the middle third
I am able to change the draft shape from fully powered up to flat now. Seems to point a lot higher. I’ll take a couple of photos next time to show both ends of the range.
T
 
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