centre board

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cathy20
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Joined: Sat Aug 01, 2009 10:13 pm

centre board

Post by cathy20 » Fri Apr 02, 2010 7:19 pm

hi,iam about to make a centre board for a moth sailing dinghy could anyone tell me the length and if possible the design thank you :D

Jools
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Re: centre board

Post by Jools » Fri Apr 02, 2010 10:01 pm

British, Europe or International Moth?

cathy20
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Re: centre board

Post by cathy20 » Mon Apr 05, 2010 1:05 pm

thank's for the reply it's an international moth

Nigel
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Location: Thornbury SC, Bristol

Re: centre board

Post by Nigel » Mon Apr 05, 2010 2:58 pm

Hi Cathy,

that is a bit more problematic. International Moths are a development class so come in lots of different flavours. If you can post some photos, somebody may be able to identify the model. It should then be easier to find another similar and copy the centreboard.

Jools
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Re: centre board

Post by Jools » Mon Apr 05, 2010 7:47 pm

Hi Cathy

I think you'll find that the Int Moth board is a much simpler form than either of the other Moth classes.
I've made a couple of boards for my two oldies and they work just fine. Start by having a read of the Hardware document here http://www.moth.asn.au/moth/?page_id=5 to get the general idea.
Pretty much every Int Moth in the 40 years has had a constant section board, just straight up and down, the same cross section. The templates here give a good idea of the section, but you want something that will go about 800mm below the hull when fully down and thick enough when painted or varnished to be a snug fit in the dagger board box.
Mine are just laminated timber, one hardwood, the other softwood. Both are about 200mm front to back to suit the boxes in my boats, made up of several strips of wood, expoxied together with the curve of the end grain alternating in direction to minimise warping. On my old 1970's boats I have no need for the carbon laminate over the top, the wood is quite strong enough, but I used something tougher and slightly heavier than Cedar, the key is not to many and only small knots in the timber. My top tip, assuming you don't have access to a planer thicknesser, is to buy the wood from a seller who does and ask for their help. I have often glued up the board, removed the excess epoxy (it's not good for planer blades) and then taken the over thickness board back and had it planed and thicknessed flat and to the thickness needed. Then cut out the shape and make the foil. Use a template for the foil and check your progress often.

Hope this gives you something to start from. I may have a suitable board blank ready for the shaping in the garage if you confirm the length, width and thickness you need; but it is really interesting to make your own too if that process interests you.

JimC
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Re: centre board

Post by JimC » Mon Apr 05, 2010 9:51 pm

Jools wrote:Hardware document here http://www.moth.asn.au/moth/?page_id=5 to get the general idea.

Pretty much every Int Moth in the 40 years has had a constant section board, just straight up and down, the same cross section.
Well, the top half anyway... Steveo's document is on the money: you'll build a good foil that way...

On the other hand if weight and ultimate quality of result is not a concern and ease of shaping is, then if you take several layers of 3mm ply to make up your blank and glue them together then the edges of the different laminations are a good guide to making it symettrical each side: you just need a belt sander, a vacuum cleaner and a very effective dust mask. if you finish it with a layer of glass then you can get away with using ordinary builders merchant exterior grade ply which will be dead cheap... It won't last for ever, especially if abused, but hey, if its your first go at foil construction you may not want it to last for ever... I have a very embarrassing rudder blade in the garage constructed in such a manner!

cathy20
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Re: centre board

Post by cathy20 » Wed Apr 07, 2010 10:40 am

hi,thanks for the information on moth centre board very helpfull, i am also unsure of how to rig up mast and sail, all i have is mast with no fittings or fixtures and a sail ( sail no 3667) if that helps , the hull had been sitting in a back garden for about thirty years so decided to rescue it and have renovated it but as you can see i am a novice on sailing dinghys but would like to get it back sailing again if there are any diagrams i can download or any information you could send me i would be very gratefull thanks

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jpa_wfsc
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Location: Oxford (Work) Coteswold Water Park (Sailing)

Re: centre board

Post by jpa_wfsc » Wed Apr 07, 2010 8:35 pm

Hi

if you were located somewhere near to any of us with old int moths, then we could be able to give some rigging advice. Interestingly, both my Skol Moth and the tunnel hulled one as seen at the WSC open the other weekend, have identical rigs... both are in the gallery and may give you some ideas, but you could get your hands on my boat at least (@ wsc) to see how that one is done.
j./

National 12 "Spider" 2523
Finn K468 'Captain Scarlet'

British Moth, 630, early 60's 'Pisces'

!!!! Not CVRDA !!!!
Comet Trio - something always ready to sail.

JimC
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Re: centre board

Post by JimC » Fri Apr 09, 2010 5:47 pm

cathy20 wrote:hi,thanks for the information on moth centre board very helpfull, i am also unsure of how to rig up mast and sail, all i have is mast with no fittings or fixtures and a sail ( sail no 3667) if that helps
Its a bit of a how long is a piece of string question... some early moths didn't have standing rigging although most did... Photos would help.

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