Triradial versus Crosscut

Yealm

Yealm

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Winter shopping !- planning to buy a new genoa for Contessa 32 on roller furling (good quality dacron for performance cruising/occasional racing).

I've got quotes for both triradial and crosscut, the latter a bit cheaper.

Should I go crosscut - on the assumption that triradials are not so good for reefing as the fibre direction will not be optimally aligned with the forces and be more likely to stretch ?

Grateful for advice,

Paul
 
Generally speaking roller furling imposes constraints on the shape of the sail so that the benefits of improved shape from tri-radial cutting would be pretty much lost. I'd go for crosscut but consider a bit extra for a foam luff.
 
The answer largely depends on the axis/off-axis loading characteristics of the cloth in question. The first port of call would therefore be to ask the sailmakers what they think and why.

That said, my sense is that you are right that a tri-radial sail in the cloth/application/sail-shape you suggest may be sub-optimal
 
dom said:
The answer largely depends on the axis/off-axis loading characteristics of the cloth in question. The first port of call would therefore be to ask the sailmakers what they think and why.

That said, my sense is that you are right that a tri-radial sail in the cloth/application/sail-shape you suggest may be sub-optimal
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The radial fibre is strong one way weak the other.

He suggests cross cut maybe better if i reef a lot.
And radial if I change to smaller sails when wind gets up (though in practice I doubt i would ever do that in a cruising context - doubt anyone does?!)

But interested in other people’s opinion/experience :)
 
Whatever you choose a foam luff (or equivalent) is essential for decent set when reefed.
With a boat like that most of the drive comes from the foresail, so I would want as good as possible rather than the cheapest.
I would go radial, and not seen any issues reefing a radial cut sail if got a decent foam luff.
 
Radials for roller furling have the problem that there's an awful lot of seams congregating at the head and tack.
Seams are thick and add to the thickness of the corner reinforcements that are already there.
This means when you start to roll you have a lot of thick, stiff material at the top and bottom of the roller, exactly where you don't want it, mitigating to some degree the advantage of adding a foam luff to the middle portion.
So that's why the sailmaker says go for cross cut if your sail is going to be your one and only sail which will be deeply reefed when necessary.
 
Yealm, I would suggest checking the grade of sail cloth, and have Vektran over Dacron for longer life. Definitely have a foam luff.

The final thing to check is how the sacrificial strip is fitted. Cheaper sailmakers cut costs by using a 4 ply leech, but the best is a 6 ply leech. It is more expensive but will be cheaper each time the sacrifial is replaced as the leech does not need to be rebuilt.
 
Concerto said:
Yealm, I would suggest checking the grade of sail cloth, and have Vektran over Dacron for longer life. Definitely have a foam luff.

The final thing to check is how the sacrificial strip is fitted. Cheaper sailmakers cut costs by using a 4 ply leech, but the best is a 6 ply leech. It is more expensive but will be cheaper each time the sacrifial is replaced as the leech does not need to be rebuilt.
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Many thanks, yes the one I'm thinking of has some Vektran.
 
Yealm said:
Should I go crosscut - on the assumption that triradials are not so good for reefing as the fibre direction will not be optimally aligned with the forces and be more likely to stretch ?
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This argument sounds odd to me. I would have thought that fibres in a triradial sail will always be better aligned with the forces, even if somewhat reduced when roller reefed, compared to the alignment you would get with a cross cut sail.

Motor_Sailor said:
Radials for roller furling have the problem that there's an awful lot of seams congregating at the head and tack.
Seams are thick and add to the thickness of the corner reinforcements that are already there.
This means when you start to roll you have a lot of thick, stiff material at the top and bottom of the roller, exactly where you don't want it, mitigating to some degree the advantage of adding a foam luff to the middle portion.
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Maybe some truth is this, but wouldn't a good sailmaker be able to compensate for this effect by adjusting the thickness and size of the compensator (foam or other material)?

For me, the strongest argument for choosing triradial construction was the prospect of having a sail that will retain a decent shape for longer, that is adding extra years before replacement is due. (North Radian, 26 sqm, in service since 2012). Still looks good, but time will tell...
 
I bought a triradial from North in their posh cloth, the name escapes me but probably Vectran or their equivalent. They admitted that triradials in standard Dcaron were not a good idea. Its a great sail and has a rope rather than a foam luff.
 
For a couple of different boats I've bought new genoas in the last 6 or 7 years.

Both cross cut, fabric upgrade and foam luff. Both have set beautifully.

Bought both from Kemp sails who also went aboard and measured up my boats. They weren't as cheap as the numerous discount Chinese lofts but then their sails were great, fitted easily first time and sailed very well.
 
Speak to Peter Sanders at Sanders Sails if you haven’t already. He makes a lot of sails for the CO32 and he is always very happy to give advice. We’ve bought 5 or 6 sails from him. No connection.

We have a triradial. I don’t think it’s a good idea to reef these on a roller fuller because of the dynamic loads on the seams so when it needs a reef it gets rolled away and we put up a #3 on an inner forestay.

I think trirradial cut sails are supposed to last longer as they are less prone to stretch.
 
On my Moody 31 I had a triradial laminate sail which was excellent, and it was 130% with a foam luff. Probably smaller than on your boat. However after 11 seasons it was showing it's age and starting to crack slightly . I replaced it last year and decided to down size even more ( old age and a bad back) to a 115% sail. After discussion with the sailmaker this time I have plumped for a cross cut in a good quality dacron. The sailmaker thought that it was not worth the triradial cut on a smaller sail. I didn't reef the old one very often and I will reef this one even less.
We discussed foam/rope luff and decided to go without . He said that the price for a foam luff was the same fitted at source or fitted at a later date, and that i could try it for a season then have it fitted if i wanted it. I have only reefed it once or twice this year so will continue without the foam luff.
If your sail is a large overlapper and you are going to reef a lot then it may not be to your advantage to have a triradial as others have said.
 
Yealm said:
Many thanks, yes the one I'm thinking of has some Vektran.
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+1 for Vektran - and I thnk if you go with that then cross cut is fine.

Peter Sanders is a good man for sails for Contessas and the like.

What size Genoa are you looking for?
 
NDG said:
We have a triradial. I don’t think it’s a good idea to reef these on a roller fuller because of the dynamic loads on the seams so when it needs a reef it gets rolled away and we put up a #3 on an inner forestay.
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Never heard of this before. It would be interesting if you could give some further information on what is at risk here. And how the dynamic loads on the seams are different compared to when the sail is not furled.
 
Go for foam luff not rope like I did. I ended up having the rope removed and a tapered foam strip put in - sets so much better than the rope luff when rolled up a bit.
 
BabaYaga said:
Never heard of this before. It would be interesting if you could give some further information on what is at risk here. And how the dynamic loads on the seams are different compared to when the sail is not furled.
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I understood it is because you are pulling disproportionately across the seams on the front part of the sail, once it is partially furled, rather than along them as is the case when fully unfurled. Happy to be corrected as I don’t claim to be an expert.
 
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