G'day,

Does anyone have any details of the weight/thickness/type (csm, rovings, coremat) of glass that goes into a mass produced solid glass cat hull?

Thanks.

regards,

Rob

talk to bret at windrush.. probably your best bet..

Who makes 1970s style solid fiberglass hulls anymore? Certainly not modern International Moth builders!
I would say look to the Gougeon Bros.

Try your question here
http://www.boatdesign.net/forums/forumdisplay.php?f=20
But don't tell them I sent you! <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

I could well be wrong.. the "hire cats" would I suspect be solid glass mat construction still. Solid allows a moron proof boat.
I doubt if hobie has changed its construction methods for the H16.. I believe Brett still builds Windrush 14s so that is why I suggested him..
Since Harry in in Perth it a local call

Are you building a solid glass laminate boat?

Hobie 16 changed to foam sandwich a long time ago.

Dart 18 is about 4mm thick but is a fairly lightly loaded hull

Most "solid" glass laminates were laid up with two laminates of 450gm/sqm CSM with extra reinforcing at load points. If it was a "coremat" (either 2mm or 3mm) composite then the CSM was two laminates of 300 gm/sqm, one either side of the core. With lighter weight foam cores then the laminates varies greatly depending on the type of “glass/carbon/Kevlar” to be used.

G'day,

Thanks Darryl, I figured on a layer of 200 gsm glass instead of the csm either side of 2mm coremat, but will do some tests to see. About 3 kgs /sqm, plus veil and gel, which is not a lot heavier than a foam laminate on 8 sq m of hull and decks.

Bvinning
I have been asked to design a car toppable harryproa (harriette) for kids to learn on. Standard spec: light enough to car top, easy to rig and sail, cheap to produce, safe, indestructable, fast etc. Not sure if it will happen, but it is fun rethinking the build for mass production and checking out the options.

Thanks to all who replied.

regards,

Rob.

200 gm/sqm either side of 2mm coremat may be a “light” finished laminate but it will also be a very flexible laminate with fairly low impact strength and also require extensive internal "framing" for rigidity integrity over any reasonable square area, which could negate any weight savings if/when going to such a light lay-up. Two laminates of 200 gm/sqm CSM plus 2mm coremat plus resin would equal approx’ as low as 1.2kg/sqm to 1.5kg/sqm depending on how well the resin (polyester) is distributed (these weights assume that the person laying up these laminates is able to remove all the excess resin, if not then the weight will regularly result to be approx’ 30% plus higher if “amateur” built due to over resining) PLUS the extra weight for any additional reinforcing framing. The better glass to use for a Coremat laminate would seem to be CSM rather than any woven product, which in practice delaminates much easier than the CSM with impact and/or excessive flexing.
For two laminates of 300gm/sq CSM plus 2mm of coremat plus resin equals approx’ 1.8kgs to 2kgs/sqm.
With the heavier laminate, over 60% of any internal framing can be accomplished using “bare” polystyrene, epoxy resined or siliconed into place, but with the lighter laminate then approx’ 90% of internal framing would require rigid (heavier) framing, IE marine ply or better still, semi rigid PVC foam sandwich constructed “frames” and bulkheads – six of one, half a dozen of the other?

G'day,

Many thanks, Darryl.

I did the numbers and we have decided to go with vac bagging, foam and epoxy as the value added is so much higher than the cost. The hulls are pretty round, so based on other, bigger boats, we will not need any internal framing apart from a bulkhead at the mast and beams.

I am now looking at QC issues, see new thread.

regards,
Rob

Are you relying on an internet forum to qualify a production boat laminate schedule? <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

You really should be talking to a professional (boat builder, naval architect, composites engineer) that can give you accurate and dependable info?

Apart from the naval engineer, I qualify fully to your criteria (plus additional engineering qualitications).
LOL Darryl.

I'm sure your info is more than sound, just questioning the means of obtaining it. We all know how careful we need to be with info obtained on the internet, particularly for a commercial venture such as this.

G'day,

Information from someone who is hands on for a project like this is of equal or more benefit than information from an NA. Unless you paid a lot of money, an engineered laminate would be heavier than required, with a note on the bottom to copy the industry standard. Consequently, advice form someone with as much experience as Darryl is very important.

My request was to determine the industry standard so I could compare it with what I have used in the past for performance laminates. Tests to do this are under way.
Regards,

Rob