I have no idea if this is resonably possible.
Are there moulds that can be hired?
Any good books available?
How much would the material cost be for a carbon 12?
Rick
This link may help.
http://www.national12.org/downloads/amateur_building-2004v1-foam_sandwich[LowRes].pdf
Rick,
I have heard carbon's a nice idea, but very expensive due to the expansion of the space/aero industry and consequent reduction in availables.
I think Mike C. would agree with me on that.
Given the lightness of carbon and the flexible, shock resilient qualities of wood I personally wonder whether it wouldn't be a bad idea to do a wood carbon fusion study? I.e. wood at half the weight/thickness, made stiff in the appropriate places by carbon. That way money would be saved on carbon and you'd still get a weight reduction. Would that work in principle? Any answers you boatbuilders out there?
Jim N3130 (Wood and carbon - together?)
We all know carbon has become more expensive but I would still guess there is a big labour cost in a boat and if you were prepared to do that yourself what would you save?
Also - is it feasable for an unskilled person to attempt a carbon home build?
Rick
Rick
If you're thinking about hiring a mould that means you must be thinking of an existing shape. One or two designs exist in mould form in the hands of designers or home builders that you would be able to hire/borrow. The other shapes are owned in mould form by the professional builders. One option might be to get the hull moulded professionally and then do all the rest of the work yourself. Graham and Zoe did this with Babel Fish and they would happily tell you what was involved.
Mike D
N3496
Rick,
As I understand it home build is perfectly possible, and indeed there are enough examples to assume this is correct. You do need a suitable heatable space and a few tools like a vacumn pump.
There are moulds available for hire, I have one and I can think of others that would be probably be available if wanted. Obviously this depends what shape you want to build. Other amatuer builds have been to their own designs.....
Somebody else will have to help with costs and books, it has never occured to me to do this so I never looked into it. It is a bit of a myth that these boats are built of carbon, the carbon in most of our boats is only used to re-inforce and stiffen where necessary the expoxy foam they are built from.
Antony
All interesting stuff - I quite fancy the idea of getting my hands sticky building a boat but don't really know enough about the process.
Bit more homework required - in the mean time I think I need to learn to sail the one I have.
Rick
Hi Rick,
I have a Foolish mould available for hire and would probably also consider loaning out the Big Issue 2 although thats likely to be more time constrained.
Anyone can home build if they have a bit of patience and are willing to ask the right people the right questions!
Cosmetic carbon is hard to get hold of and pricey (I.E. you want to leave the boat in that nice pattern finish) but other cloths are still available at a more reasonable price. Glass with carbon reinforcing is the most cost effective and can still have up to 20 k's of lead in.
Anyone who wants to talk about this a bit more, I will be at Grafham (Moth open too!) and can spare an hour for anyone who wants to ask q's...
Cheers
Mike C
PS, Sorry Jimbo, cant see any benefits in wood sandwich... Lighter and stiffer with foam.
To get a wood with equivalent panel stiffness you would end up with about 4 or 5 layers of carbon on top of 2mm ply to get anywhere near the same stiffness as say 5mm foam with one layer of carbon on each side. (all best guesses)
Panel stiffness goes up with the square of the thickness, so you can have really stiff but light foam panels at 8 or 10 mm thick but with still only one layer of carbon and naff all weight.
5x as expensive as foam, because you have that much more carbon and 5 x more resin. then it would be cheaper to buy a foam panel instead. you would still have to vacuum bag the carbon, especially with that much cloth and resin. And then you still have something that is heavier than a foam sandwich panel. If I can build a boat with 15-20 kg of lead in and dare can build a wooden one with a couple of kilos in, that will be the difference as you dont save weight anywhere, youve just paid lots to do it...
Wood grows on you? better get that seen to...
Thanks for the info. Mike. Very focussed. Very confident.
I'm not sure however I'd want to go that way, since I have the feeling - like many others (Tim & Co for example) who sail our N12's regularly - that what really counts is getting out on the water in your N12 and putting the hours in. There are those who like playing chess and those who just like making the chess boards and pieces for others less fortunately technically endowed and also those like Dare, who do both.....
Come back to the class and get some N12 in !!!!!!!!!!
As for wood growing on me, a regular pruning is all I need at the moment :P :P :P
[quote by=Mikey_C link=Blah.cgi?b=Cool,m=1160992213,s=9 date=1161027855]To get a wood with equivalent panel stiffness you would end up with about 4 or 5 layers of carbon on top of 2mm ply[/quote]
But why would you use 2mm ply Mike? Andy Paterson used to make some very satisfactory Cherubs with 4mm floor and all the rest 3mm ply with 105gsm glass each side. The thicker is easier to get, easier to work with and probably cheaper too. If I build the Canoe I've half promised myself over the winter that will be 3mm ply, probably 100hsm glass on the outside and 200gsm carbon on the inside.
Then he will pretty much end up with what Dare Barry is already building. I think Jimbo was enquiring as to the alternative to that.
Fact is that wood is nowhere near as good a core material as foam if you are going to the trouble of laminating it all up. A 12 is a big boat for its size, lot of surface area and that adds up with the core...
The joy of composite is you pick whatever does the job, if you want to build a wooden hull and put carbon decks on it, you can. If you want a composite hull and put wooden decks on it you can. You will end up with a nice halfway house on cost and weight.
Thinking backwards, you could probably do a lightweight boat in 1mm Ply/foam/Ply. would still require vacuuming/epoxy and all that, but would be pretty light and reasonably stiff...
Mike!
It's a halfway house on cost and weight I was looking for.
I don't assume there'll be a weight reduction in the near future. If there is one, it probably won't be more than 5-6 Kg. To recap, aside from the environment issues, my question was mainly pitched because of the relative expense of carbon, which is light, compared to wood, which is not expensive, but heavy.
Ok. I'm not a boat builder, I just like sailing, but If such a compromise were reached it might be of interest....
Jim N3130 (Wood working )
I've a few views on the questions possed above.
Yes there are plenty of moulds out there. Dave Greening has the Annies Apple mould and will lend it out for free without timelimits. (assuming he hasn't chopped it up for some space in his garage)
As for the wood carbon technology - it is acceptable for cherubs and moths because they are not as wide and are therefore not subject to high twisting loads. National12's are exceptionally wide and really do suffer from twist if the build isn't done right. Added to that - single sided laminate on 3mm wood is very weak on impact - Tom Edoms moth suffered a catastrophic puncture on his first outing.
Also remember that ply will not form complex curves so you are limited to chined or stressed ply hull forms. The improvements in hull speed since plywood days can be attributed to both stiffness/weight and hull shape's which are just not feasible in stressed ply.
finally - the cheap route to a modern hull is e-glass composite. e-glass is about 1/10th the price of cosmetic carbon and 1/6th price of raw carbon weave. Structural foam and epoxy however are still rather expensive.
Matt
Suggest a look at the Merlin site - Photos- Lawie Smart boat. I build a Cherub like this 15 years ago. Just buy in the panels from Martel Composites
Hi Rick, would be happy to talk to you about our home building exploits (Our front room is pretty much back in order now). The costs came out pretty good, you are right that labour is the biggest part (forunately our internal recharge rate was pretty low). We did have to buy a new dining room table afterwards which wasn't in the original budget.
Are you going to Grafham?
Also, have you read the building guides in the members area? http://www.national12.org/private.shtml
Can't make GWSC as I am doing a Musto Skiff coaching weekend.
No immediate plans to build so will talk to you when we meet.
Good luck at the weekend.
Rick