In mast furling replacement main.

Chris_Robb

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Hi, I need to get a new main sail (in mast furling) made for my Westerly Oceanlord which is currently in Levkas Greece. A local sailmaker has the sales and is quoting for a Square Weave Dacron - Tri-radial sail.

1. What is the operational difference in Marblehead and Square weave (which has I believe thicker strands woven in at 90degrees. ?

2. If Square weave is better, is it much more money?

3. Is it sensible to have a tri- radial cut ( as opposed to cross cut) on an in mast furling mainsail? Will the extra thickness of the cloth cause jamming? I say this becasue the boat next to us once had such a sail and spent most of the afternoon trying to unjam it.

In many respects I would prefer to have the sail made in the UK, but I have a very tight measurement of the boom's height above the Bimini hood (centre cockpit) so at least a local sailmaker can make it fit! Sail makers are Waypoint sails in Levkas - any references on them? I have heard good things about them in Levkas........ and they make a lot of inmast furling sails for the charter yachts apparently.
 

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Chris,

I claim no expert knowledge of this subject but am currently having a new mainsail being made by Kemp at Wareham. The guys at Kemp are, in my experience, very knowledgeable and helpful. With the new sail there have been a number of innovations (as compared to the one they made for me in 2006) which are:

1) Better, which I understand to mean more densely woven, sailcoth. Apparently it withstands the repreated furling better than the previous cloth used. It is more expensive.

2) Short vertical battens; gives better sail shape and gives support to the leech to prevent the dreaded "hooked" sail. This also allows much less "hollowing" of the leech which I'm not sure I entirely understand but I do know that again it increases sail area and removes some of the disadvantage of an in-mast sail.

3) The top of the headsail can be slightly wider which increases sail area by about 1 sq m overall (which represents about a 3.5% sail area increase)

I know that some of these points are rig specific, we have a Selden mast which can accommodate the aforementioned which I don't think is true of all spar designs.

I hope that helps a little bit!

Rob
 

Chris_Robb

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Chris,

I claim no expert knowledge of this subject but am currently having a new mainsail being made by Kemp at Wareham. The guys at Kemp are, in my experience, very knowledgeable and helpful. With the new sail there have been a number of innovations (as compared to the one they made for me in 2006) which are:

1) Better, which I understand to mean more densely woven, sailcoth. Apparently it withstands the repreated furling better than the previous cloth used. It is more expensive.

2) Short vertical battens; gives better sail shape and gives support to the leech to prevent the dreaded "hooked" sail. This also allows much less "hollowing" of the leech which I'm not sure I entirely understand but I do know that again it increases sail area and removes some of the disadvantage of an in-mast sail.

3) The top of the headsail can be slightly wider which increases sail area by about 1 sq m overall (which represents about a 3.5% sail area increase)

I know that some of these points are rig specific, we have a Selden mast which can accommodate the aforementioned which I don't think is true of all spar designs.

I hope that helps a little bit!

Rob

Thanks Rob. I think I will avoid battens of any sort, but it is really the suitability of a tri radial cut that worries me.
 

pvb

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Thanks Rob. I think I will avoid battens of any sort, but it is really the suitability of a tri radial cut that worries me.

Doesn't triradial construction allow you to have "stepped" fabric weights, so that the sail can be fairly lightweight overall?
 

pvb

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Kemp Sails say "radial cuts can be useful in less obvious situations - like the design of in-mast furling mainsails, for example. Radial design lets you ‘step’ the cloth weight, using heavier material in the highly-stressed leech, and lighter fabric for the main body of the sail. This way, the overall weight is reduced - and so is its bulk, which means it takes up less space inside the mast and will furl up more easily."
 

cmedsailor

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Two years ago I bought from Quantum Hellas a bi-radial in mast furling main sail made from dimension-polylant's square 310 cloth. Very good material (probably one of the best dacron available in the market), very strong and holds its shape.
Two years later the sail still looks as new.

Their opinion was that a tri-radial is not necessarily needed for in mast. Bi-radial is equally good (I think it's because once you furl it in stronger winds tri-radial will not offer anything more than a bi-radial). The cloth was heavier and "harder" than older cross cut (it becomes more soft with time) but due to been new was and still is much easier to furl in comparison to old one. It still doesn't have any greases (is this the correct word?) but this is really up to good furling, it doesn't mean you can furl it anyway you like. The mast is a Sparcraft ocean model.
 

Talulah

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Thanks Rob. I think I will avoid battens of any sort, but it is really the suitability of a tri radial cut that worries me.

We have had 4 in mast furling mainsails.
All 4 have been made in Vectron (Hood then Kemp).
The Hood/Kemp mainsails were well made and have been excellent.
3 of them were fully battened with a Roach, the 4th has no battens and no Roach.
Having had a great deal of use of both battened and unbattened I would never bother going back to battened. More trouble then their worth.
The battened are great when they're new. However, the top batten pockets are reinforced/padded. This adds extra thickness. Consequently the top pockets start chaffing. Once the chaffing starts the thickness of the sail at this point gets thicker. This leads to more chafing and vicious circle of extra thickness/extra chaffing is set up.
Once you hit a critical thickness the sail starts jamming as it comes out and extra care has to be taken to check the top batten pockets are coming out and not getting stuck in the mast channel. None of these problems exist with the batten free sail and I really don't notice the loss of Roach.
I would add that most owners probably don't experience the wear on the top batten pockets as their annual mileage is probably a small fraction of ours. However, if you are off for some long term sailing then from my personal experience I would recommend not having battens.
 

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I would add that most owners probably don't experience the wear on the top batten pockets as their annual mileage is probably a small fraction of ours. However, if you are off for some long term sailing then from my personal experience I would recommend not having battens.

Thank you for that; I will raise it with the sailmaker.

Robert
 

Talulah

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Thank you for that; I will raise it with the sailmaker.

Robert

Robert. I see that your new main is being made by Kemp. The fact that we have had 4 mains and 3 Genoas from them (inc Hood) is an indication of how pleased we were with their service, quality, support etc.
The one remaining fully battened main is still as new and only brought out on race days.
I have no experience of using short battens. However, I deliberately avoided short battens because once a sail jams the first step in freeing it is to remove the battens.
With full height battens you can remove these at deck level and then continue to unjam the sail. With short battens it's not so easy.
 

GAJ

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Over the years that I kept our boat in Preveza I had Nick and John from Waypoint renew the standing rigging, make a bimini with side curtains, stackpack, cockpit dodgers, and they built me a new standard battened mainsail. I found them to be very knowledgeable, their work to be excellent and their prices to be fair. If they build the sail for you they can fit it and tweek it if necessary. Please pass on my regards to them, they knew me as Mr Graham from Stargazer.

We now have in-mast furling with a tri-radial cut sail. Amel have been using the tri-radial cut for all their sails for many years and continue to do so, so they must be all right mustn't they?
The only comment I would make is that if the sail is built using different weights of cloth it is possible to overload and stretch the lighter panels if the sail is carried in too much wind as the previous owner of our boat must have done, which required the sail to be re-cut.




Hi, I need to get a new main sail (in mast furling) made for my Westerly Oceanlord which is currently in Levkas Greece. A local sailmaker has the sales and is quoting for a Square Weave Dacron - Tri-radial sail.

1. What is the operational difference in Marblehead and Square weave (which has I believe thicker strands woven in at 90degrees. ?

2. If Square weave is better, is it much more money?

3. Is it sensible to have a tri- radial cut ( as opposed to cross cut) on an in mast furling mainsail? Will the extra thickness of the cloth cause jamming? I say this becasue the boat next to us once had such a sail and spent most of the afternoon trying to unjam it.

In many respects I would prefer to have the sail made in the UK, but I have a very tight measurement of the boom's height above the Bimini hood (centre cockpit) so at least a local sailmaker can make it fit! Sail makers are Waypoint sails in Levkas - any references on them? I have heard good things about them in Levkas........ and they make a lot of inmast furling sails for the charter yachts apparently.
 

Chris_Robb

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Robert. I see that your new main is being made by Kemp. The fact that we have had 4 mains and 3 Genoas from them (inc Hood) is an indication of how pleased we were with their service, quality, support etc.
The one remaining fully battened main is still as new and only brought out on race days.
I have no experience of using short battens. However, I deliberately avoided short battens because once a sail jams the first step in freeing it is to remove the battens.
With full height battens you can remove these at deck level and then continue to unjam the sail. With short battens it's not so easy.

Thanks for that background. Battens always looked like trouble waiting happen, so I like to follow the KISS principle.

Tri Radial versus Cross Cut - the sail needs to be non stretch and flat - yes the sails are rotten in terms of performance compared with a conventional main, so why try to make a silk purse out of a sow's ear.... So Cross cut ticks the box here.

So it comes down to the strength of the sail cloth. so which one for Cross cut?
 

Kurrawong_Kid

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Had a tired Maxiroach with full length vertical battens which did get jammed. Trouble was you couldn't get the batten that was jamming the sail out, because it was in the mast!
Bought a new Dolphin with 3 vertical battens up by the leech. Much better sail shape than no battens and, so far, they have come out O.K.. Do need, though, to take care when furling to see they furl parallel to the mast and when unfurling to operate the outhaul sensitively so there is a bit of tension, but not too much, to entice the battens out of the mast.
 
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