I'm about to place an order for a new genoa for cruising & racing on my
24' boat, and have received a bewildering array of styles and prices,
from a straight cut Dacron genoa to a tri-radial Kevlar laminate genoa.
Priced in the middle are materials such as Twaron, Polykote and Pentex.


A big deal is made of sail cut. The Dacron sails are usually offered
straight cut (Non radial cut) and the laminated fabrics seem to be
offered more radially cut than not.

Does the stretch of a Dacron sail produce the required shape (In the
middle of each panel) and outweigh the need to have the additional
radial panel pattern?

Am I best off going for a laminated genoa that is non-radial cut,
rather than a radial-cut dacron genoa? (Some sailmakers offer
attractive prices on Twaron laminate, not radially cut)

Am I better off paying more £ for a sail with a radial cut in Dacron
or a laminate, just the laminate or not for either? (Just going for a
sail in a laminate with a straight cut)

Many thanks in advance for your opinions and experiences

Artie

"Arturo Ui" wrote in message
oups.com..
..
I'm about to place an order for a new genoa for cruising &
racing on my
24' boat, and have received a bewildering array of styles
and prices,
from a straight cut Dacron genoa to a tri-radial Kevlar
laminate genoa.
Priced in the middle are materials such as Twaron, Polykote
and Pentex.


A big deal is made of sail cut. The Dacron sails are
usually offered
straight cut (Non radial cut) and the laminated fabrics seem
to be
offered more radially cut than not.

That doesn't mean that the panels are sewn together
''straight''.

Does the stretch of a Dacron sail produce the required shape
(In the
middle of each panel) and outweigh the need to have the
additional
radial panel pattern?


Sail Construction

Camber is created in sails by a combination of broadseaming
(the panel edges
are curved before sewing together) and luff curve (the sail
is wider in the
middle; when put on a nearly straight mast the excess cloth
produces camber).
The name "broadseaming" comes from the earlier practice of
overlapping the
cloth more near the ends of the seams than at the middle;
now we trim off the
excess.

Early cotton sails were very stretchy, and most of the
camber was induced by
luff curve. Although the excess cloth that produces camber
is all along the
luff, stretch allows the depth to move towards the middle
of the sail.

Modern sails of low stretch cloth are made with the camber
produced by
broadseaming, and the luff curve is matched to the mast.
This gives MUCH better
control over shape, as the seam contour puts the camber
precisely where you want
it rather than where stretch happens to put it.

http://cerebus.winsite.com/laser/arc.../msg00666.html




Am I best off going for a laminated genoa that is non-radial
cut,
rather than a radial-cut dacron genoa? (Some sailmakers
offer
attractive prices on Twaron laminate, not radially cut)

Am I better off paying more £ for a sail with a radial cut
in Dacron
or a laminate, just the laminate or not for either? (Just
going for a
sail in a laminate with a straight cut)

Many thanks in advance for your opinions and experiences



You need to tell us where / what type / what boat, sailing
you're doing.

Scotty

I would think a cross cut Dacron sail made with a high performance
cloth would be fine for a 24 foot boat. If you wanted to step it up a
notch go with a tri-radial laminated sail which uses Dacron or Pentex
between the mylar skins. Any sailmaker who is pitching you on Kevlar
or any other exotic (read expensive) cloth for a 24' boat is not
serving you. This is assuming of course that you are not going Grand
Prix racing. A good friend who has owned 2 lofts (major franchises)
told me once that the use of exotic crap on boats smaller than 30' is a
waste since the loads just arn't there.

Arturo Ui wrote:
I'm about to place an order for a new genoa for cruising & racing on my
24' boat, and have received a bewildering array of styles and prices,
from a straight cut Dacron genoa to a tri-radial Kevlar laminate genoa.
Priced in the middle are materials such as Twaron, Polykote and Pentex.


A big deal is made of sail cut. The Dacron sails are usually offered
straight cut (Non radial cut) and the laminated fabrics seem to be
offered more radially cut than not.


That's because of the difference in the direction each one
uses it's strength... unless the Dacron is woven with
heavier or straighter threads in one direction, then the
panel orientation will matter less than the filler, finish,
and of course weight of the cloth. The laminated sails try
to get the direction of the strongest threads running mostly
in the direction of the stress on the sail, a comples business.



Am I best off going for a laminated genoa that is non-radial cut,
rather than a radial-cut dacron genoa? (Some sailmakers offer
attractive prices on Twaron laminate, not radially cut)


Ringmaster wrote:
I would think a cross cut Dacron sail made with a high performance
cloth would be fine for a 24 foot boat.

Especially for a light air sail.

.... If you wanted to step it up a
notch go with a tri-radial laminated sail which uses Dacron or Pentex
between the mylar skins. Any sailmaker who is pitching you on Kevlar
or any other exotic (read expensive) cloth for a 24' boat is not
serving you. This is assuming of course that you are not going Grand
Prix racing. A good friend who has owned 2 lofts (major franchises)
told me once that the use of exotic crap on boats smaller than 30' is a
waste since the loads just arn't there.


Agreed. Although the sail can be made of lightweight stuff
that will depend on the panel orientation... and IMHO the
seams... to keep it from blowing out quickly, light a medium
#1... bad idea for longevity though.

A lot of smaller one designs are using mylar laminates, but
that may just be because they look cool. The stresses are
small so the sail could last forever if it were never
flogged or crumpled.

Fresh Breezes- Doug King

Artie,
You don't say exactly what kind of Racing you're doing, If you're racing
with the hot fleet, it would be a good idea to get the fastest sail
possible

On the other hand if you are just racing with the back off the fleet and
cruising is just as important then you do have a choice to make.

I'll give you my selection and reason but that my selection and I can't
say it right. I sailed with a self furler, I finally settled on a Kappa
Cut 10-40 regulator 150% a damn fine headsail for most condition but a
light air sail it was not. I also had a cross cut drifter that I could
use in the track or when Cruising I'd fly it free behind the furled 150
Kappa cut.

Art, I raced in the Cruising Class and I had great fun. Best of all, it
made my crew commit to one nite a week to sailing. My goal was to stay
with the fleet.

Good luck on your decision.


http://community.webtv.net/tassail/ILLDRINKTOTHAT

I finally settled on a Kappa
Cut 10-40 regulator 150% a damn fine headsail for most condition but a
light air sail it was not.

What was the problem as a light air sail? I should think a 150 would be
primarily for light air use.

My sail is 150%, for use in 0 to 15 knots of wind. What is a kappa cut
and why didn't yours set well? My genoa is for a masthead rig, I'm
likely to be getting a Twaron (like Kevlar) laminate genoa, straight
cut panels, and for a reasonable price in comparison to having a
similar sail (With Kevlar-branded Kevlar) for about £200 more.

My original question surrounded the use of straight cut panels (I know
they have 'draft' cut into them!) vs. a radial cut, which to my
uneducated eyes would seem to allow more of a 3d-type shape to be cut
into the sail. The sailmaker seems to think it makes little difference
in this material.

Any comments before I undo my wallet and cough up to my sailmaker?

Many thanks

Artie

What was the problem as a light air sail? I should think a 150 would be
primarily for light air use.


Arturo Ui wrote:
My sail is 150%, for use in 0 to 15 knots of wind. What is a kappa cut
and why didn't yours set well? My genoa is for a masthead rig, I'm
likely to be getting a Twaron (like Kevlar) laminate genoa, straight
cut panels, and for a reasonable price in comparison to having a
similar sail (With Kevlar-branded Kevlar) for about £200 more.


Sounds like a pretty good compromise. If the panels are
heavy enough to stand up to 15 knot winds, you'll be giving
up a bit of performance in very very light airs. But nothing
is perfect even if you carry two 150 genoas.


My original question surrounded the use of straight cut panels (I know
they have 'draft' cut into them!) vs. a radial cut, which to my
uneducated eyes would seem to allow more of a 3d-type shape to be cut
into the sail. The sailmaker seems to think it makes little difference
in this material.


It can make a difference in the weight of the sail... a
radial cut can use a lighter weight cloth. In a boat less
than 30' LOA or 9.2 meters, the weight saved is probably not
worth the cost. But radial cuts don't respond as well to
tuning either, their shape is mostly locked in. So if you
are an active type sailor then you would probably be happier
with the cross cut.

Fresh Breezes- Doug King