Last weekend at the Isotope Nationals I borrowed a pair of Carbon Sails. When I first picked them up I noticed they were about half the weight of the pentex/dacron sails. An extreme weight savings 20+ feet in the air turns into horizon job for the competition. They kept there shape well and I did very well concidering the light wind circumstances. There hasen't been any other mention of this incredible speed advantage. Has other fleets experienced this? [color]
J.P.Ayers
Isotope 186
A friend of mine recently purchased a set and your right they are very light, but the cost is heavy. I'm waiting to see how they hold up.
They're not class legal in most catamaran classes.
"They're not class legal in most catamaran classes. "
You mean like, one-(manufacturer)design classes ?? 
We`ve seen this before, mylar sails are still outlawed in many class rules that were written in the `70`s, despite them having become cheaper and more durable, hold their shape longer etc. I guess the reason might be that if, in your particular boat`s class rules, it states that you have to buy your sails from one supplier, normally after being marked up by the "license holder" (ie manufacturer), it`s not in their best interest that the buying public have sails that last indefinitely and have a long racing life.
That`s the cost of "keeping the costs down" 
I am probably the person that catman speaks of.
Light?....yes, very. Costly?...like anything else in life, that is a personal matter. Class legal? I am sailing a P19 platform with Tornado spin/spin pole/snuffer. Nothing class legal about my boat. The sails were custom built to be as close to Tornado sails as possible; given our mast height differences. Heck, they used carbon sails to race around the world. That should say something about how they hold up.
Dave
I think most fiberglass factory production cats are about 100lbs. heavier than the could be if the industry would switch to carbon fiber hulls, masts, boards, rudders, beams and sails.
The argument against it is "Carbon is too expensive..." but if the entire industry were to swith and suppliers could make it in bulk, wouldn't the cost come down quite a bit?
The light aircraft industry is slowly changing over from aluminum to carbon and the prices are pretty much the same but the finished product is both lighter and stronger.
I am probably the person that catman speaks of.
Light?....yes, very. Costly?...like anything else in life, that is a personal matter. Class legal? I am sailing a P19 platform with Tornado spin/spin pole/snuffer. Nothing class legal about my boat. The sails were custom built to be as close to Tornado sails as possible; given our mast height differences. Heck, they used carbon sails to race around the world. That should say something about how they hold up.
Dave
I think most fiberglass factory production cats are about 100lbs. heavier than the could be if the industry would switch to carbon fiber hulls, masts, boards, rudders, beams and sails.
The argument against it is "Carbon is too expensive..." but if the entire industry were to swith and suppliers could make it in bulk, wouldn't the cost come down quite a bit?
The light aircraft industry is slowly changing over from aluminum to carbon and the prices are pretty much the same but the finished product is both lighter and stronger.
There is an echo in here....
There is an echo in here....
I have had a set of cuben fiber sails on my P-19 since early last year. Huge difference in performance. Zero stretch, less weight and holding up well so far.
Salud
What? Can you say that again?
What? Can you say that again?..
Fibergalss is basically mined from the ground as sand, then refined. That's why it's cheap. Carbon fiber OTOH,is a synthetic product with a complex and costly manufacturing process. Unless some new miracle process emerges, the cost will not go down anytime soon. The "synthesized mesophase pitch" method of production was supposed to be that miracle method, but the cost has not come down.
The economics and mechanics of boat vs light plane manufacturing are so completely different that such a simple comparison certainly becomes a bit simplistic, I'm sorry to say. The choice in light aircraft is between structural aluminum and carbon/epoxy, NOT glass and carbon. BIG difference. The savings in aircraft manufacturing comes not mainly from weight savings, but labor, because the parts count is so much lower for carbon/epoxy. Remember that metal aircraft are mostly riveted together, and that this is still done mostly by hand, one rivet at a time. Carbon/epoxy has allowed aircraft makers to build large structures in molds with significant automation and far fewer labor hours.
Structurally, riveted or bonded high-strength aluminum still competes well with carbon/epoxy, but I for one would never buy an aluminum boat built from one of those corrosion-prone high-strength alloys. Corrosion problems are bad enough with masts and beams even though they are generally made of lower alloys like 5052 or 5056.
It's like comparing apples to boiled eggs! 
Jimbo
What?
Boats are already made in molds in few pieces. No savings in labor can be expected by switching to carbon/epoxy like there is for airplanes. So the boat just costs WAY more to build in carbon/epoxy. No way around it.
Carbon won't be getting cheaper anytime soon. In fact, the price is expected to rise because the manufacturing process is energy intensive.
Fiberglass has never been competitive in airplne structure because it lacks stiffness. Riveted aluminum is better structurally than fiberglass, though laborious to assemble.
Airplanes are getting more and more carbon/epoxy structure mostly to save labor ($$$) not weight.
Get it?
Jimbo
There ARE cheap sources of carbon!
At any Wal-Mart you can get a 20 pound bag of Kingsford charcoal for $4.00.
Jimbo, I got it the first time, my "What" was in reference to the echo effect with all the double posts, the forum seems to be having problems.
The real reason you don't see carbon/epoxy or even glass/epoxy boats is most builders don't have the facilities. A competitive carbon/epoxy boat requires an autoclave (a computer controlled pressure chamber/oven) and metal molds. A polyester/glass boat is done in open molds that can be wood or better( And NO NACRA does not make the A2 in their facilities)
The extra cost of carbon and epoxy is minimal, less than $500 per boat. It's paying for the facility that costs so much. You have to use the facilities 24/7 to make them pay. That means your whole line has to use them or you have to take in outside work. That why there is not much overlap between the polyester/glass builders (F18) and the epoxy builders
However, from what I have seen, the increase in quality and durability is worth the extra money. For example, based on Tornado experience you could build an F18 with a 10-14 year competitive life for the hulls.
From carbon sails to carbon hulls..
The T's hold up so well becouse they are overbuildt (minimum weight is to high for Marstrøms pre-preg-autoclave work). Now, the F-18's are even heavier, so if some builder started producing F-18's with the same methods it would probably be bulletproof as well as long lasting. But I dont think the F-18 sailors will be willing to pay Tornado prices for their boats.. About US$ 27.000,- last time I checked.
There also a shortage of carbon today. The plants was probably not ready for Boeing and Airbus's latest models. New plants are coming online, but this takes time.
We are saying the same thing. Using an autoclave and epoxy/glass you could build a near bulletproof 18 ft 400 lb cat
As far carbon, the plants WERE prepared for Boeing and Airbus. The plants signed long term contracts to sell most of their production to the big companies. It's the rest of us that are in trouble
That makes sense Carl!
I dont think the rule. "carbon is expensive" is true these days..
A fully prepreg carbon nomex I 14 hull is 5% more expensive then a foam/carbon glass hull..
*shrugs*
The smaller builders here in Au are gearing up or already have geared up for prepreg carbon boats..
They use low temp uni prepreg which is comparable in cost or a little higher that some glass products.. (from memory $20 AuD a square meter 150 gm uni?) So two crossed layers +45/-45 for skins a little overkill but..) for the outer skin and a third layer of kevlar or glass for impact areas..
They use glass/vynl molds and simple wooden "ovens" with heater bars to "cook" to 100C.. Basically a box wich fits over the mold and the coils turned on for a set time.. With a thermo swicth to control the temp..
However the guys need to learn to vac a mold for good results..
Sorry to be beating "my own drum" here, but in the F16 class we allow carbon pretty much everywhere. Carbon rudderstocks and rudder/daggerboards are still less than halve the price than the glass/alu stuff from our competitors.
Stealth marine offer a full carbon set of hulls for only 1000 pounds more, on a total glass package price of only 6700 pounds. This standard package already includes a carbon mast.
It is my experience that certain carbon mast makers charge high prices for their products but that this is alo wholy unrelated to the price of the carbon cloth itself.
"Carbon = expensive" is simply not true
"certain builders/supplier = expensive" very much is true.
Wouter
Let's go over this again for those who don't read the whole thread.
Carbon is not expensive
To go from polyester/glass to epoxy/carbon is around $500 (hand lay-up)
However to get the best results, you need an autoclave. An autoclave will greatly improve the quality and repeatability of your composites. You can make it lighter for the same strength or stronger for the same weight compared to room temp and pressure cure
A 20 ft autoclave will cost $100,000 - $4,000,000. plus facilities. (The more expensive, the easier to use, the more boats at one time and the higher the pressure) If you are only building 100 boats a year, that is expensive.
If you own an autoclave you want to use it to build everything your company makes, to help pay for it. That is why most companies don't build polyester/glass and carbon/epoxy boats.
Using an autoclave you could build a 400 Lb 18 ft fiberglass catamaran that would last 15+ years
As for non-autoclaved epoxy composites, I would build my boat using them, I might buy a boat using them, I would NOT get on an airliner built using them. The quality of non-autoclaved composites is mixed, Sometimes it works great, sometimes it delaminates. It is rare for prepreg autoclaved composites to delaminate.