Main Sail Cloth Weight

[cutlass]

a quick question-

im buying a new mainsail for my 39 ft catamaran. One manufacturer recommends 9 oz cloth, the other 10oz. Is 9oz ok or do I really need the heavier?

Im taking the boat across the pacific so I want sails that will last!

thanks a million

[GordMay]

It's a judgement call.
Sail cloth weight is generally a function of anticipated sail loading:
sail size (square footage), usual wind conditions (speed), and boat size/displacement.
Offshore & cruising sails are generally made a little heavier than racing/multi-purpose sails, sacrificing some boat speed and windward performance for more durability.

[cdennyb]

I'm no expert by any means but offshore, across the pacific... I'd personally go with the upper end of available and suggested cloth weight. And a few extra reinforcement threads at the corners would be nice too.

[bullsails]

the weight itself is not the real issue. The construction of the sail in fibre layout (warp yarns to fill yarns) is far more significant. I would much rather have a mainsail cut from 9oz Strong Fill sail orientated cloth (assuming it is a crosscut sail) than a 10oz balanced cloth or a budget cloth. If the mainsail aspect of luff to foot is higher than 2.5 -1 then you need a specialised cloth. Find details of what material they are actually using? Weight only can be quite misleading.

[Bash]

It really depends on the cloth. A lighter, quality cloth will both outlast and outperform a heavier, cheap cloth.

[cutlass]

thanks for your replies!

the cloth will be crosscut. Its high aspect from Challenge

[Bash]

Originally Posted by cutlass

thanks for your replies!

the cloth will be crosscut. Its high aspect from Challenge

Ask your sailmaker what he thinks about a tri-radial main built with Challenge 8.11 oz warp-drive dacron. You may spend a few hundred extra, but the sail will hold its shape a few years longer. And it will sail circles around any 10 oz crosscut out there.

[bullsails]

Challenge High Aspect will be fine for the job.

[Katiusha]

When we were shopping for new sails, we ended up going with a cloth lighter by 1 oz than original sails, but from a sails loft that swore by the cloth quality. Haarstick Sailsmakers test each roll that they receive for strength, stretch, cloth blemishes, etc and if found, that roll is sent back. That struck a cord with a QA engineer in me and we chose them for our new sails. Their sail design is also very good. And they guarantee their regular cloths to 30-35 kn, whereas guarantee at other sail lofts was up to just 15-25 kn.

So far the sails (shape, cloth, stitching, etc) have held up for 3 years of use and abuse with both sails used during light winds and heavy storms. Our sails, being from a lighter cloth, work much better in light airs, and are still strong enough to handle heavy storms.

Thus, for us, the guarantee of the sail cloth by the sail loft is more indicative of quality than the cloth weight.

[norsearayder]

my new offshore main is warrentyed for 5 years and 50000 miles and sails like a foil

[S/V Alchemy]

Originally Posted by cutlass

a quick question-

im buying a new mainsail for my 39 ft catamaran. One manufacturer recommends 9 oz cloth, the other 10oz. Is 9oz ok or do I really need the heavier?

Im taking the boat across the pacific so I want sails that will last!

thanks a million

It's not a quick question.

For long-distance oceanic voyages, I would consider having two mains: a lighter one for lighter airs (up to say 25 knots with perhaps one reef in) and a heavier one for driving the boat above that, and with the lighter one having two reefs and the heavier one three.

I have never sailed a cat, but I would imagine the need to depower a sail is perhaps greater given the inherently more tenuous grip on the ocean that a cat has compared to a monohull. So you need, perhaps, more 'gears' with which to use the wind effectively, if safely.

[rhumbunctious]

Originally Posted by norsearayder

my new offshore main is warrentyed for 5 years and 50000 miles and sails like a foil

Do tell....

[LH44 Anne]

Originally Posted by S/V Alchemy

[snip]

For long-distance oceanic voyages, I would consider having two mains: a lighter one for lighter airs (up to say 25 knots with perhaps one reef in) and a heavier one for driving the boat above that, and with the lighter one having two reefs and the heavier one three.

Taking a main off and bending it again after repairs or to substitute another at the dock is a major PITA. You want to do it under way because the wind is piping over 25 knots? That makes you a better man than me, Gunga Din!

[bobconnie]

In the past I always went with the heavy sails for cruiseing, but with the new matieral available these days if I have to replace sails I will sure look at some of the new stuff as Ive seen some new sails around that really work well!! and sorta look great also !! The Motor Sailer Im In process of trying to buy has Older sails that have Not been used in in YEARS, and have the feel and look of almost new sails of 10 oz dacron ! they have been coverd at all times, altho I wont be looking for new ones to soon but I sure will look into the new materials.

[LH44 Anne]

Anyone with experience with HydraNet sail cloth? It's fairly new, from Dimension Polyant, and has Dyneema (Spectra) reinforcing of dacorn weave. Seems an interesting way to go, but I'd like to hear about experiences of "early adopters" if there are any out there.

For those who want to know more, see http://www.dimension-polyant.com/en/Hydranet_2_2_1.php