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I just bought a used sunfish that has all the parts except for the rudder and daggerboard. I would like to build my own replacements because these parts are pretty expensive new and I thought that it would be a good project.

I need help deciding on which type of wood to use. I believe that they are usually made of mahogany but I heard that red oak can also be used as a less expensive alternative. I considered using marine grade plywood buy I am not sure if it would be appropriate.

Also, I have the specifications for the parts and I am pretty handy but I am not exactly an expert on wood working. Any tips on how to shape the edges would also be appreciated.

I would choose white oak over red. Red oak isn't rot resistant like white oak.

Hi

I did use mahogony for the daggerboard and rudder on my Bull's Eye. However the plans to give option for marine plywood.

If you already have the patterns / specs for them and I think properly epoxy encapsulated marine ply will work just fine.

As for shape you are going for efficiency through the water, so rounded edges at the leading edge coming to a thinner trailing edge on both sides. If you are going the use the plywood I would suggest shaping with a belt sander, followed by a random orbit prior to expoxy.

You might want to leave the leading edge "robust" in case it strikes something.

Cheers

Mark C

thanks for the tips. I am probably going to go with oak instead of plywood.

Would you suggest using a belt sander to shape the edges?

Also, what is the correct way to finish the wood? Would a few coats of polyurethane do the trick?

Hi

If you are going to use solid wood.......I would turn to my handplanes and spoke shave. If you don't have a spoke shave I would use a block plane. Most of the work would be to thin out the training edge and about one third of the width in front of the training edge. The leading edge needs the corners planed off and thinned slightly so it enteres/cuts into the water. This needs to swell over the first third to the full final thickness, and the centre third is the transition nicely down into the final third (ending at the trailing edge).

Since this is not a one design / racing application the exact shape is not critial but it does need to fit the boat and any other hardware required to attach it for use.

As for a finish.....Question: Will the boat be dry-sailed? If it lives on land most of the time and only in the water for use, I would not worry about using glass and expoxy. I would finish it with about 7 to 8 coats of UV stabalized marine varnish, or paint. You will need to keep any eye on deep scratches/dents etc and touch them up as required. If the boat is to be left on a mooring with the foils left in the water I would suggest you should encapsulate the wood in epoxy prior to the same finished as in the previous sentence. Epoxy itself is not safe from UV light and will degrade, so it needs to be protected with some kind of UV protection coating.

You can see a bit of how I did mine here: http://www.glen-l.com/picboards/picboard15/pic754a.html

Hope this helps.

Cheers

Mark C

I vote for marine plywood.

I don't have bad experience with solid wood... but I can say that I am still sailing the original rudder and daggerboard on a boat that my father built in 1967.

No splitting, no warping.

_________________
Bruce.

~~ Do what you love, and love what you do. ~~
~~ To me - only my boat is not yet perfect. Everybody else's is to be admired for I know the path they have walked (Dave Lott, 2010) ~~
Dow's Monaco Project

Hi

Bruce makes a good point.......the dagger board and rudder I built out of mahogony mostly because I like doing that sort of work and wanted to have a set finished bright. Of course then you feel really obligated to keep them looking good.

As far as usability goes I'm of the mind that marine ply is the way to go. I took great care to ensure my wood ones would stay flat and you don't need to bother with that extra work when you use ply. If you are going to be having children use the boat and/or you expect rought usage then a quick coat of paint every couple of years will keep a plywood one protected, looking good, and you won't agonize over every scratch and dent.

I was thinking of building a second of the daggerboard, and rudder but i would make the rudder a kick-up type. I definitely would use marine plywood. I don't regret building the first set, but a second set in ply will keep the originals looking better - longer!

Cheers

Mark C

so if I were to use ply, how would I properly seal it so prevent it from becoming delaminated?

The ply is only going to delaminate at the edges and it will do it fairly rapidly. Regardess it is the best choice in my opinion for all the reason stated previously. You must protect the edges while the surfaces are remarkably durable. Perhaps the best way is a few layer of glass and sanded smooth?
Just want to add, not all marine plywood is created equal. Make the choice with great care.

Stuart

I think my 45 year old daggerboard has two or three coats of varnish on it.

I could not guess the decade when it was last recoated. It is solid as a rock.

If I were to do it today, I would encapsulate it in epoxy before varnishing. I would give the edges two or three coats, then put two or three coats over the whole thing.

As Stuart said.. starting with some fiberglass tape on the edges would certainly not hurt.



Maybe they don't make marine ply like they used to???

_________________
Bruce.

~~ Do what you love, and love what you do. ~~
~~ To me - only my boat is not yet perfect. Everybody else's is to be admired for I know the path they have walked (Dave Lott, 2010) ~~
Dow's Monaco Project