I just bough a new 135% genoa, for very cheap considering it never has been taken out of the bag, it has the sunbrella already sewn in but it is too long in luff for my roller furler. I was wondering what you thought about cutting the sail down by just taking a slice out of the leach. I mean lop the head off the 2 1/2 feet or so I need to fit the sail and taper the cut down to nothing at the clew. Or would this destroy the shape of the sail and I'm better taking it all off the luff even though it involves resewing the sunbrella?
Recutting a genoa
- Thread starter scupper
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I cut 3' off the top of a genoa for a HR25 and sewed the line back in to the luff.
I had to shorten the bolt rope and splice a new thimble into the top.
It works. OK only. Next time I'll have a sail maker do it.
The shape is not quite optimal...
Here is a link to a video I did running dead down wind. https://www.youtube.com/watch?v=IgF4Xzh_GsU
There are a couple other videos of the same sail on that channel.
Note: Look at the main sail. I cut that down form a Shark sale. I cut a chunk out near the bottom and made 3 pieces to get my correct boom length. Just sewed them all back together. Double sided tape is very handy to have. (See the sailright.com videos.)
It works OK. (I did come 2nd in the keel boat class in the last regatta...)
The boat I sailed this year is a Siren 17.
I had to shorten the bolt rope and splice a new thimble into the top.
It works. OK only. Next time I'll have a sail maker do it.
The shape is not quite optimal...
Here is a link to a video I did running dead down wind. https://www.youtube.com/watch?v=IgF4Xzh_GsU
There are a couple other videos of the same sail on that channel.
Note: Look at the main sail. I cut that down form a Shark sale. I cut a chunk out near the bottom and made 3 pieces to get my correct boom length. Just sewed them all back together. Double sided tape is very handy to have. (See the sailright.com videos.)
It works OK. (I did come 2nd in the keel boat class in the last regatta...)
The boat I sailed this year is a Siren 17.
Id recommend to cut the foot instead of the leech for the following reasons:
If you cut the leech, tapering the cut towards the clew, you'll be cutting through the area of broad-seaming at the head of the sail, thus leaving the upper section of the sail with a permanently 'twisted off' shape. Broad-seaming is the 'tapering' of the panels edges near the luff and is what promotes the 3-dimensional or 'cylindrical-like' shape, especially from the leading edge back to where the maximum draft occurs.
Good sail design practice includes that the aft leech area be parallel to the boat's centerline for beating/pointing. Cutting off and 'tapering' some of the leech violates this design 'rule of thumb' and leaves the leech shape in the upper panels in a permanently 'twisted off' shape.
Cutting off some of the foot doesnt involve altering the 3-dimensional shape, per se. If the height of the clew is already far enough above the deck, etc. you can simply taper from where you cut through the luff back to the clew ... and have only one area that needs to have a new (tack) cringle added and to be re-reinforced with new 'reinforcement patches' if needed.
If cutting off just a few inches of luff length, then usually there is no need for new 'corner patches' just a new tack connection - easily done with a "D-ring" and nylon webbing ... and some 'sail tape' to cover the rough edges of the panel edge ... OR a - 1-1/4" 'folding over' - of the bottom edge of the foot panel.
Rx: cut the luff at the foot and taper back to the clew ... you wont be disturbing/changing the sail's 3D shape. ;-)
If you cut the leech, tapering the cut towards the clew, you'll be cutting through the area of broad-seaming at the head of the sail, thus leaving the upper section of the sail with a permanently 'twisted off' shape. Broad-seaming is the 'tapering' of the panels edges near the luff and is what promotes the 3-dimensional or 'cylindrical-like' shape, especially from the leading edge back to where the maximum draft occurs.
Good sail design practice includes that the aft leech area be parallel to the boat's centerline for beating/pointing. Cutting off and 'tapering' some of the leech violates this design 'rule of thumb' and leaves the leech shape in the upper panels in a permanently 'twisted off' shape.
Cutting off some of the foot doesnt involve altering the 3-dimensional shape, per se. If the height of the clew is already far enough above the deck, etc. you can simply taper from where you cut through the luff back to the clew ... and have only one area that needs to have a new (tack) cringle added and to be re-reinforced with new 'reinforcement patches' if needed.
If cutting off just a few inches of luff length, then usually there is no need for new 'corner patches' just a new tack connection - easily done with a "D-ring" and nylon webbing ... and some 'sail tape' to cover the rough edges of the panel edge ... OR a - 1-1/4" 'folding over' - of the bottom edge of the foot panel.
Rx: cut the luff at the foot and taper back to the clew ... you wont be disturbing/changing the sail's 3D shape. ;-)
The only thing I'd add to Rich's post is this:
I agree its best if you can cut a 'wedge' off the foot, starting at the tack and tapering to clew. If this works (meaning the clew clears the deck after the tack has been brought down), also make sure you also have a good sheeting angle from your genoa leads. Often boat's genoa tracks do not go far enough forward to support correct sheeting angles on very low-clewed sails.
I agree its best if you can cut a 'wedge' off the foot, starting at the tack and tapering to clew. If this works (meaning the clew clears the deck after the tack has been brought down), also make sure you also have a good sheeting angle from your genoa leads. Often boat's genoa tracks do not go far enough forward to support correct sheeting angles on very low-clewed sails.
You may find that this sail is not such a good deal if it has to be altered that much. I would check with a sail maker (the original one would be best) and see what they say about the modification and cost.
Ok apparently I need to supply more information. So the cut of the sail would be fine if I could have a deck sweeper but I have solid handrails the whole boat so the sail needs to be about 2-3 feet shorter, the clew and tack are both too low. I use a block on a rope on midships cleat as my sheeting adjustment (think barber hauler) so have the full bulwark as a sheeting angle so no problem there.
I don't think I'd be able to purchase even the material for a sail for anything close to the 50 bucks this one cost me (450 square foot sail), so cutting it down whatever way is best I think makes the most economic sense, especially if I can cut it down by just altering one side and not having to re-adjust the broadseaming in the luff.
This is a spare sail and I'd like to do the alterations myself in an attempt to learn something but I don't really know what would be the best alteration to attempt.
This is what I understand are my options:
There's the cutting the slice off the leach, I suppose there's cutting a larger square panel off the leach too, though I'd rather not shorten the sail area that much. I was under the impression that the upper 1/3 portion of head sails usually have no broadseaming that usually the leach hollow takes care of the shaping there, so that if I were to take a couple feet off the head then I could taper the cut back to the clew and end up with a slightly lower aspect jib. Though I may have to flatten out the uppermost broadseamed panel? This way I was thinking I could re-use the head patch and mostly leave the clew patch alone. My thinking was that this would preserve the angle the foot make to the deck and shorten the hoist while only changing the sheeting angle slightly, which I can adjust for easily. The other reason is ease of sewing, I have a decent old singer from the fifties that sews sails quite well but has a tiny throat and having to roll the sail up to sew and cross sail panels usually presents problems whereas running the machine along the leach is trouble free.
Then there's cutting the foot down either tapered or straight, i don't think that it would give anything decent of a shape if I were to cut 2 1/2" feet off the tack and taper it back to the clew, the clew would just be too low to get tension on it without the leach falling off, it would be something like tapering a whole panel of sail cloth. but again only having to re-sew 1 1/2 corner patches. I like this option second best as again I would at least be able to fit what ever sail I need to into the machine if all the sewing is at the foot. Why I don't really want to go this route is I was also under the impression that there is a significant amount of shaping in the foot of the sail and if I were to cut of the foot then I'd have to do some re shaping up along the luff, maybe I'm wrong?
And there's also cutting down the luff which would involve re-broadseaming all the panels and the head and tack patches which I'm trying to avoid it would however let me leave the sunbrella mostly alone.
I don't think I'd be able to purchase even the material for a sail for anything close to the 50 bucks this one cost me (450 square foot sail), so cutting it down whatever way is best I think makes the most economic sense, especially if I can cut it down by just altering one side and not having to re-adjust the broadseaming in the luff.
This is a spare sail and I'd like to do the alterations myself in an attempt to learn something but I don't really know what would be the best alteration to attempt.
This is what I understand are my options:
There's the cutting the slice off the leach, I suppose there's cutting a larger square panel off the leach too, though I'd rather not shorten the sail area that much. I was under the impression that the upper 1/3 portion of head sails usually have no broadseaming that usually the leach hollow takes care of the shaping there, so that if I were to take a couple feet off the head then I could taper the cut back to the clew and end up with a slightly lower aspect jib. Though I may have to flatten out the uppermost broadseamed panel? This way I was thinking I could re-use the head patch and mostly leave the clew patch alone. My thinking was that this would preserve the angle the foot make to the deck and shorten the hoist while only changing the sheeting angle slightly, which I can adjust for easily. The other reason is ease of sewing, I have a decent old singer from the fifties that sews sails quite well but has a tiny throat and having to roll the sail up to sew and cross sail panels usually presents problems whereas running the machine along the leach is trouble free.
Then there's cutting the foot down either tapered or straight, i don't think that it would give anything decent of a shape if I were to cut 2 1/2" feet off the tack and taper it back to the clew, the clew would just be too low to get tension on it without the leach falling off, it would be something like tapering a whole panel of sail cloth. but again only having to re-sew 1 1/2 corner patches. I like this option second best as again I would at least be able to fit what ever sail I need to into the machine if all the sewing is at the foot. Why I don't really want to go this route is I was also under the impression that there is a significant amount of shaping in the foot of the sail and if I were to cut of the foot then I'd have to do some re shaping up along the luff, maybe I'm wrong?
And there's also cutting down the luff which would involve re-broadseaming all the panels and the head and tack patches which I'm trying to avoid it would however let me leave the sunbrella mostly alone.
If youre handy with a (heavy duty) sewing machine a sail needle and sail twine: cut the foot - higher on the luff to higher on the clew, reattach the sun-cover.
The alternate is to sell the sail and buy new ... or bite the bullet and have a sail loft do the alteration. When you get into 'corner' alterations, this involves a lot of expensive 'handwork'.
The alternate is to sell the sail and buy new ... or bite the bullet and have a sail loft do the alteration. When you get into 'corner' alterations, this involves a lot of expensive 'handwork'.
Akin to "slab reefing" then. I imagine then I would be able to leave the drafting in the whole rest of the sail untouched?
I think you are assuming a straight cut along the foot. Realize that it can be cut in a mild curve to achieve the belly that you want or don't want. This is one of the shaping methods a loft uses to pull a too deep belly out of an old mainsail. A convex cut pulls the belly flatter. Chief
I meant straight as in keeping the same angle to the deck that it currently has rather than tapering it from way up the tack and down to the clew it currently has. Straight like a slab reef. I would also like to maintain the right angle to roll it up onto the furler which I think having any taper would screw up.
So other than cutting some belly away from the foot of the sail is there any shaping that goes on in the foot of a genoa?
The foot of most jibs/genoas are 'mostly' straight; if you put in a lot of convex curve on the foot, you'll probably need a 'purse line' - similar to a leech line.
You can copy/scale the boat designers tack & clew angles from:
(S36-2) http://sailboatdata.com/viewrecord.asp?class_id=3806
(S36) http://sailboatdata.com/viewrecord.asp?class_id=1735
You can copy/scale the boat designers tack & clew angles from:
(S36-2) http://sailboatdata.com/viewrecord.asp?class_id=3806
(S36) http://sailboatdata.com/viewrecord.asp?class_id=1735
Look on Sailrite.com. They have instructions on converting a sail to roller furling which includes shortening the luff to make room for the furler. They recommend striking a new luff shape from the existing tack to where you want the new head to be on the leach. The existing luff has some shape to it that must be transfered to the new luff.
3 feet might be more than that technique can handle, though. Give them a call, they are always happy to help. They also have great prices on the tools and supplies you'll need, the best I've been able to find.
3 feet might be more than that technique can handle, though. Give them a call, they are always happy to help. They also have great prices on the tools and supplies you'll need, the best I've been able to find.
Yeah I believe cutting three feet out of the luff would necessitate re-broadseaming the whole sail as you'd be cutting off all the shaping all the way along the luff and in that case I'd rather just pay the sailmaker a few hundred bucks and have it done rather than trying to sew the panels back together mid sail. That I know is beyond my patience with the machine I have. just sewing along one of the outside seams is no problem as long as there's no more than a couple feet of sail to jam into the throat of the machine. I imagine I could use a similar technique to transfer the same shaping into the new foot of the sail if I were to cut it off.
I re-cut a sail like this before, well sort of, I just remove the second to the bottom panel (near foot) and re-sewed the old foot back on copying the same stitch line that was on the panel I cut off, then I jut had to trim the protruding part of the leach and re-sew the clew patch and leach line.