Phill,
If I recall correctly the 100 gm uni was less than half that of 200 gm woven carbon. So two layers of uni were the way for home builts if one wanted to use carbon.. Three around the case area (or kevlar).. Twin layers would be all one would need internally.. I dont recall what the cost was of kevlar prepreg...
When I did the maths years ago the cost of a prepreg carbon nomex wasnt that much more than the cost of a wet epoxy glass layup..

I suspect infusion is a little out of the home builders area.. But it looks good..

Saying this... The F16 highish weight doesnt require the use of these methods... But the infusion makes sense for commercial builders..

Stewart

It's really not a big point, or relevant to this thread, but for some reason I always tought Marstrøms M-20 was pre-preg carbon?


For some photos from Marstrøm's operation:
http://watersportscheveningen.nl/marstrom1.php http://watersportscheveningen.nl/marstrom2.php http://www.multihulls.org/marstrom.html

Notice the large autoclaves in the last link, and that they still set up the boats before fitting beams etc. Not wholy industrialized yet..

Windrush in Westren Australia is also offering prepreg Tornado Hulls that are the same hull shape as the current Masrtoms for quiet a reasonable price. I believe they are about AUD$13,000 for a set of hulls

Stewart,
I agree when talking about uni for pre preg.
From memeory 200gm plain weave pre preg was aound $70 per m2 while uni was around $24 per m2 at 200gm. However the lighter the fabric he more costly. From my calculatrion at the time hulls built from pre preg uni are quite cost effective but as soon as you introduce plain weave the cost goes thru the roof.
In addition to this you have to buy a full roll of pre preg uni and this has to be factured into the overall cost.
On the other hand plain weave can be bought around here at a min of 5 m2.

As indicated in my last post there are other considerations. As this subject interests me so much I'd be happy to call you to discuss.
The real problem is hulls are usually built of glass not carbon. The diff between the cost of pre preg glass and wet layup is huge.
It really gets to me when the Tornado class say you can not use cabon in the hulls but it is OK to use pre preg plain weave glass. This blows me away.

Actually infusion is more within the realms of the home builder than pre preg. With Infusion you need a good vacuum pump however in pre preg you need the vacuum pump and an oven.
There are different infusion methods that also need an oven but really this is moving more towards the pre preg methodology.
As I said before, happy to call you some time to discuss,
I find this advancement in production techniques facinating and I'm very happy that NACRA are moving into the 21st centuray with a number of other manufacturers. All we need now is Hobie to come up to speed and we could start to get some hulls that have realistic weights.

How are things going with your F16.
I'm very interested!
Fancy a chat some time. I still want to come over to sail around Rotnest. It's been over 20 years since I was on Rotnest and kicking myself I didn't bring my cat , a Mossie at the time.
I will never forget the waves with the really long faces and the following breese as we travelled back to the mainland.
What a ride on an F16 one up with a kite!!!!
I have a list of things I want to do and sailing from Rotnest to Fremantle is right up there.

Regards,
Phill

If I recall correctly Brett one one heat of the worlds in Perth using his T hulls.. However he tends to put his new boats in the water on the day of the invitation race or the day of the first race.. Ditto his flying moth.. He could well have won the worlds Moth title if he had a few days on water tuning.. Maybe have placed in the T worlds as well..

His last T was bullet proof.. strip layered foam..

An ultra talented skipper and builder..

Rolf,
I agree.
I thought I sighted Marstrom as an exception in an earlier post. Myn apologies if I missed this out.
They are producing hulls in an autoclave. This is by far the better way of building pre-preg hulls for cats. But it will cost. I see Marstrom as an excellent setter of goal posts but not really within the reach of mainstream.
Regards,
Phill

Hi Phill,
I dont see any advantage of using weave as opposed to uni.. Last quote I had they quoted in cut lengths!!.. This may have changed but I asked for weights I know the 18teens used!! (100 and 200 gm).. So was piggy backing on their building requirements.. A tad heavy in layup but *shrugs*..

I believe uni is the way to go anyway.. The C fibres run straighter and not kinked.

S..

Have alook at http://www.fram.nl/ where a guy has built a farrier 39 using infusion since 2002, even has videos and of all things a kit at 85Euro to try out your ideas, quite informative and a process I'll definately be giving a go at.

Weren't AHPC with the Capricorn F18 and A-cats and Vectorworks Marine with the Blade F16 earlier production cats to be build using resin infusion ?

Seems nacra has again trouble investigating their claims before mouthing off.

I suspect that we we look into it we'll find one or two other builder using infusion as well.

I know that one cruising catamaran builder is also using resin infusion for their cats.

Wouter