Refinishing Mahogany Dagger board


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The dagger board on the sunfish I just bought is looking a little bit old. Much of the polyurethane is warn off and the bare wood is exposed in places. My plan is to hand sand it a little, maybe use some marine filler in badly chipped areas and then use an outdoor polyurethane to finish and protect it. I am only looking to prolong the life of the Mahogany Dagger board. I am not trying to improve performance, do any racing and I don’t care about looks. I have a few questions for anyone who knows about this stuff:

1. Am I wasting my time? Should I just use it as a bare wood board and buy a new one in a few years?
2. Can I use “outdoor” polyurethane to refinish it or is there a marine grade I need to use?
3. Should I just glass the whole thing and paint it?

Thank you for any help, I would hate to mess it up.

Definately refinsh your blade, your time won't be wasted. You don't want to buy a new blade, they are about $120 just for the wood part. Sand the old finish off completely and refinish. You can fiberglass the blade with 6 oz. glass cloth and epoxy and have a clear, durable finish. Do not got get a polyesther resin. Epoxy, while it cost a little more, adhears better to wood, is stronger, shrinks less and is more chemical resitant. The biggest advantage to me is that it "stinks" less. West Systems, MAS, RAKA and Sytem Three are the most popular brands epoxy and can be found at marine dealers. You will still need to varnish the fiberglass with a couple of coats of a good grade of marine varnish for UV protection from a marine dealer. Do not get the hardware store variety varnish, it doesn't have the proper formulation for protection and/or durability. The guys that build cedar strip canoes use the fiberglass/epoxy/varnish method and have some great looking canoes/kayaks. The Yahoo group "cedarstripcanoes" has references and instructions on applying a fiberglass finish.

You can duplicate the factory finish with just the varnish. Deffinately not as durable and would need to be revarnished more often.

Read the thread on restoring a Sunfish rudder (about a week or so ago) and the articles in the FAQs and "Tips and Tricks" on the Sunfish Class home page for more suggestions/instructions. Good Luck.
First of all, your daggerboard is not Mahogany, it's Phillipine Mahogany which is not a true Mahogany. The ones I make are either African, or Central American Mahogany. A simple test to confirm it's Phillipine Mahogany would be to attempt to handplane with a razor sharp handplane. If it tears up the wood, it's Phillipine Mahogany. There's nothing wrong with Phillipine Mahogany. It has many of true Mahoganys desirable chacteristics. Just don't try to handplane it!

I would suggest you sand it down, either by hand, or with a vibrating handsander. I really wouldn't be too concerned with filling in any voids, or the like. As far as a finish goes, in my opinion, you have two routes to go, perhaps just one. Polyurethane it with any solvent based polyurethane that's available from your local hardware store. I use an exotic, 2 part polyurethane that's supplied by an aircraft supply house. The system will cost you $100.00. It will be enough to do many daggerboaqrds. the advantage with this product is you'll probably never have to varnish your daggerboard again!

Also, I suggest you somehow learn to distinguish between the truly knowledge people you might meet on this site, and the other well meaning ones. If you have further questions you can email me at

Al Courtines - 33yrs Sunfish experience, 27yrs teaching woodworking exp.
Hi Al

What is the 2 part polyurethane that your are using? Is it UV protective? I would love to refinish my '65 parts using a varnish that will last a long time.
I think this is one of the best kept secrets in the marine arena. I did my parts 25 years ago, and redid them this summer to freshen them up. I thought in the past 25 years this product would have caught on by now. All my info. is at my summer home. Search for Poly fiber aicraft coatings. they will direct you to a local dealer. Ask for the 2 part urethane, not the 2part epoxy. Don't be afraid to use more reducer tha they recommend.

Any Questions:


Al Courtines