One for a sailmaker...radial v crosscut

I'm about to get a new Fireball mainsail in kevlar.  When these came out they tended to be crosscut, however now there are more options available.  You can still buy a fully crosscut sail, however you can now also get a mainly crosscut sail with the area under the bottom batten radial from the clew, and also a fully radial design (eg North Sails).

Over time the Fireball kevlar main seems to develop a problem with a crease developing from the clew up through the inboard ends of the batten pockets and I understand that the semi radial or fully radial design can help stop this. 

Any sailmakers care to share some pearls of wisdom on the merits of the designs?

Thanks!!

Kite material stretches. Kevlar doesn't stretch - at least not much on a sail the size of a Fireball. I'd be surprised if cross-cut versus radial made much difference. But I'm not a sailmaker either.

Edited by Stefan Lloyd

I am with Stefan - on a sail as small as a Fireball with cloth that stable I doubt it makes any difference.

Choose what all the top guys use ...

It probably depends on the cloth - you're best off trusting the sailmaker to to have made these kind of decisions to get the fastest sail. If you suspect its only cross cut to save money, ask why it's cross cut - with most sailmakers I suspect the answer would probably take at least half an hour - I doubt few if any would just say "because it is"

On the subject of the batten pocket crease, given that it never occurred with dacron sails which are like elastic compared to Kevlar cloth, there may be other powers at work. I've heard rumours its something to do with the mast bending off sideways too much below the spreaders.....

 

Looking at it from another direction:

taken from Ullman sails web-site
( fiberpath is a load path sail technology ):

=============================================

" How FiberPath Works
     
     Why have we developed FiberPath sails? The answer is that because
the fibers in a FiberPath sail are aligned with the primary loads in the sail,
and a FiberPath sail can be built with multiple fiber patterns to address
secondary loads, a FiberPath sail has a wider range and is stronger for its
weight than a tri-radial sail. The trouble with tri-radial sails is they only
cover primary loads. Because the fibers in FiberPath sails run on top of
each other in different directions, specific loads in each area of the sail
can be handled.

FiberPath Performance Life and Longevity     

     A FiberPath sail will hold its performance shape 1 ½ to 2 times
longer than a tri-radial sail, because in a tri-radial sail it is the secondary
loads and Mylar shrinkage that ruin the shape."

============================================


So the shrinkage is from the mylar.

this shrinkage is probably more obvious in the cross cut sail because of
the bigger panels, the overall kevlar warp - weft direction and less seems
- against - more seems, smaller panels, 3D panel shape and kevlar
orientation on a radial sail.


by the way Steffan kites aren't just made from Ripstop.