Sailcloth Weight - Page 2

bewitched · 03-11-2009, 17:45

Quote:

Originally Posted by svTOTEM

Lastly, and not to be pedantic, there is no such thing as a “sailmakers oz”. .

I probably am being pedantic here - but there is:

http://www.challengesailcloth.com/pdf/measure.pdf

But does it really matter what the weight is? Today many sail manufacturers will have their own proprietary materials from which they build sails and will be much more knowlegable on the properties of those materials than even a well informed individual.

The weight of one sailmakers material is likely to vary from another's. There are therefore significant design characteristics other than weight that come into the equation.

I would argue that the pressure "window" (force per m2) that the sail is designed to operate in, is a far more relevant criteria than how heavy the material that the sail was made out of is.

svTOTEM · 04-11-2009, 08:45

Christian Van H - Thanks, we've been crusing Mexico for a year and love it; in 5 months we're off to the south pacific.

bewitched - if you go back and look at my first post on the thread, you'll see that I made the same point as what you wrote. Weight of sailcloth is about as helpful as saying I'd like to buy a sedan without giving any other information.

I could bore you to tears going on about sailcloth (probably have), but when I designed sails I spent countless hours testing cloth on a super accurate Instron machine: From Modulous of elasticity to crimp, Dacron to carbon fiber, and everything from Flying Juniors to Americas Cup boats to mega yachts. Yes, sadly, I was a sailcoth geek. I will disagree with the notion many sailmakers have their own proprietary material. A few do, but the investment to make you own cloth is huge and proprietary cloth made by one of the major cloth manufacturers is also very high.

My original point was that sailcloth weight is one general and not very helpful, variable about the cloth characterisitcs. And that the average sailor can easily learn a little about it so that they can discuss with/question their sailmaker if getting news sails (and state without hesitation that there are many sails made from junk sailcloth). Further, knowing a little (and it really doesn't take much) about sailcloth properties and you can make your sales last longer and hold their shape better because of how you treat them.

OK, I've beat this horse to death, but a smidge of sailcloth 101: Who knows what a denier is?

The definition of denier, like that of weight, is silly: It is the mass (diameter in this case) of a fiber that is 1 gram and 9000 meters long. What is helpful is knowing the denier per inch (dpi) in sailcoth.

So if cloth is 300 x 500 dpi, this means that there are 300 denier of warp fibers per inch (warp is along the length of the roll) and 500 dpi along the fill (short way across the roll or panel).

Why is this helpful? If you know you mainsail is made from 200 x 800 dpi material it is very high aspect, meaning it is much stronger in one direction. So lets say it's blowing 25 and you a reef in and your feeling fine. If the line holding the leech reef in is too far back on the boom, there is going to be excess load tranfered along the reefed foot of the sail. The high aspect sailcloth will permenantly distort, likely just past the edge of the leech reef. I'm not saying high aspect cloth is bad, because any sailcloth loaded in th wrong way will distort or break. It's not rocket science...

OK, heading out now to spend a couple weeks island hopping our from Santa Rosalia to La Paz.

Jamie

barnakiel · 04-11-2009, 18:02

Oufff....

A lot of info and it would take a looong post to explain.

In any case:

- the oz goes per yard, but the yard differs because the Brits decided to use a roll width different from the Yanks, so the numbers are not same, but close,
- the gr/m2 is a metric alternative,
- the manufacturers (sailmakers?) with known own materials are ... what? NorthSails. Otherwise Bainbridge, Contender or DP cloth is used, their own materials are mostly the laminated things they build,
- for the dacron thing it is safe to talk oz per sail area per wind conditions, add a bit for a long term cruiser (chafe), for the weekendeer deduct some,
- my experience from the inside of the loft at Doyle was that we delivered the best quality job from the best available materials, nobody is perfect but we tried hard and always gave the best advice we could,

b.

04-11-2009, 08:45	#2
svTOTEM Registered User Join Date: May 2007 Location: Cruising - currently in Mexico Boat: Stevens 47 - Totem Posts: 90	Christian Van H - Thanks, we've been crusing Mexico for a year and love it; in 5 months we're off to the south pacific. bewitched - if you go back and look at my first post on the thread, you'll see that I made the same point as what you wrote. Weight of sailcloth is about as helpful as saying I'd like to buy a sedan without giving any other information. I could bore you to tears going on about sailcloth (probably have), but when I designed sails I spent countless hours testing cloth on a super accurate Instron machine: From Modulous of elasticity to crimp, Dacron to carbon fiber, and everything from Flying Juniors to Americas Cup boats to mega yachts. Yes, sadly, I was a sailcoth geek. I will disagree with the notion many sailmakers have their own proprietary material. A few do, but the investment to make you own cloth is huge and proprietary cloth made by one of the major cloth manufacturers is also very high. My original point was that sailcloth weight is one general and not very helpful, variable about the cloth characterisitcs. And that the average sailor can easily learn a little about it so that they can discuss with/question their sailmaker if getting news sails (and state without hesitation that there are many sails made from junk sailcloth). Further, knowing a little (and it really doesn't take much) about sailcloth properties and you can make your sales last longer and hold their shape better because of how you treat them. OK, I've beat this horse to death, but a smidge of sailcloth 101: Who knows what a denier is? The definition of denier, like that of weight, is silly: It is the mass (diameter in this case) of a fiber that is 1 gram and 9000 meters long. What is helpful is knowing the denier per inch (dpi) in sailcoth. So if cloth is 300 x 500 dpi, this means that there are 300 denier of warp fibers per inch (warp is along the length of the roll) and 500 dpi along the fill (short way across the roll or panel). Why is this helpful? If you know you mainsail is made from 200 x 800 dpi material it is very high aspect, meaning it is much stronger in one direction. So lets say it's blowing 25 and you a reef in and your feeling fine. If the line holding the leech reef in is too far back on the boom, there is going to be excess load tranfered along the reefed foot of the sail. The high aspect sailcloth will permenantly distort, likely just past the edge of the leech reef. I'm not saying high aspect cloth is bad, because any sailcloth loaded in th wrong way will distort or break. It's not rocket science... OK, heading out now to spend a couple weeks island hopping our from Santa Rosalia to La Paz. Jamie __________________ s/v Totem www.sv-totem.com

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04-11-2009, 18:02	#3
barnakiel Registered User Join Date: Aug 2009 Location: between the devil and the deep blue sea Boat: a sailing boat Posts: 919	Oufff.... A lot of info and it would take a looong post to explain. In any case: - the oz goes per yard, but the yard differs because the Brits decided to use a roll width different from the Yanks, so the numbers are not same, but close, - the gr/m2 is a metric alternative, - the manufacturers (sailmakers?) with known own materials are ... what? NorthSails. Otherwise Bainbridge, Contender or DP cloth is used, their own materials are mostly the laminated things they build, - for the dacron thing it is safe to talk oz per sail area per wind conditions, add a bit for a long term cruiser (chafe), for the weekendeer deduct some, - my experience from the inside of the loft at Doyle was that we delivered the best quality job from the best available materials, nobody is perfect but we tried hard and always gave the best advice we could, b.