Use it as a template to make another. Buy hardwood grade ply... do your best to fair the wood in the same places as the original. 4-6 coats of captains spar varnish, or cetol... and you are Good to go.
I took another look at the blade. At the top where it would be in the hull when fully inserted appears flat. At the bottom, it is cupped such that there is a 3/16" gap at the center when a straight edge is placed accross the daggerboard width. I wonder if I could remove an 1/8" from the outer third of the width to restore the flatness. The daggerboard is 36"LX11"wX3/4"t. Does this sound doable?
phughes200 good idea grind it flat coat it with coats of west systems epoxy so it wont warp again if that wont work use your old one for a templet find a lumber yard in your area that sells baltic burch plywood russian import plywood comes in 5foot x5 foot sheets cut it out with a jig saw router the edge round or hand sand smooth coat it with epoxy slap on a coat of anti foulent if needed go sail.
Guys.... I owned a zuma... vanguard used oak plywood as the "standard" for years. We aren't talking a boat on a mooring, it won't be under water except while being sailed. Yes epoxy would hold up better, but then formed lexan might too!
NO I wasn't recommending buying a new daggerboard, but depending on whether he races, it MAY be the RIGHT thing to do. The ZUMA is a One Design racer MUCH like a Laser. These are racers who shave seconds off by using the right wax on the hull!
Anyway, making one the hardest part would be getting the "shape" of the daggerboard to match that (because there are flat, and faired pieces on the board, it isn't just a flat board through the hull, it is cut angled, with blocks for stoppers, and thinned spots).
Also, since you say the original is warped (not delaminated?), you MAY be able to strip the original varnish off, soak it in water (feels like the wrong thing to do), then warp back the opposite direction in the sun as it dries keeping it bent the wrong way slightly as it dries MIGHT get it closer to square again.
I do not race. I was hoping to try to fix it before buying a new one. I thought of soaking it and then clamping it until it dries out. Wasn't sure that it would work. The other thought was to remove enough wood to elminate the bow and resealing. This would mean some reduced strength but I suspect it will be okay. This would get my daughter back to sailing in a week. A new board would take 3-5 weeks to get.
Buy enough wood to build 2 then. Finish grade hardwood ply from home depot.
Make one that is nothing more than a board faired fore and aft, and fits into the slot... generally cut out to the same shape as the old one, this is your "temporary"
Then use the original to shape the 2nd one you can take your time to match as closely as you can the original... You can then plane it a little, or a lot.., If you do varnish, plane it a little... if you do epoxy, plane it a lot, so there is room for the finish in the daggerboard slot.
You can get her on the water with a straight board really, it won't be the fastest, or the best, but it will work until a suitable replacement is made/purchased. It'll work.
My experience with the Wayfarer is that the strongest construction is fibreglass, or at least epoxy, over plywood, with a final coating of a few coats of varnish.
I had problems with water penetration into my rudder which was varnish over plywood. I stripped it, and painted a couple of layers of West System epoxy on it. It's thin enough to brush on like paint. Finally added a couple of layers of varnish.
The problem is that without the epoxy, the varnish gets scraped off the tip of the rudder or board when beaching or whatever, then water gets in.
People have also been known to put a metal strip over the bottom tip of the board and rudder, for protection.