I accidentally put a curve into my WD12 hatch cover which I was able to repair by cutting a kerf into one layer of the wood, clamping the hatch cover flat and filling the kerf with epoxy/woodflour mix.

Don't know if that'd work as well for you,  but click on the picture to get to a description of what I did. Any chance you could post a shot or two?

Good luck,

Laszlo

Usually warping results from a chanage of moisture content.  Ie one side of a board drying more (read heat, sunlight) or the other side absorbing moisure.  The moisture makes the wetter part swell and causes wood to curve the away from the moist area.  The solution which sometimes works is to dry the apex of the curve.  You can try gentle heat and time.  one traditional way is to wet the side the board curved towards. then put it wet side down on a flat surface and let the sun dry the other side.  Clearly there is a lot of trial and error in this.  How it got damp or dry may give you a clue. 

good luck.  Ed.

Now to try to unwarp my strip built petrel.  Got the inside glassed and then had to stop for several months.  the outside absorbed moisture that the inside couldn't.  Used heat lamps from several feet away to dry the outside and have it most of the way back.

Got some pictures here for your reference.

 Hopefully this should give you a better idea of what we're dealing with.

 Alexa and Thomas 

Was hoping someone would have a good suggestion. Because I don't know if there's any good way to get them straight, and to make them stay straight.

I'd probably glue up some new foils from solid lumber, which I think are preferable anyway. Rip the stock into lengths a couple inches wide, and glue up the blanks making sure the orientation of the growth rings alternate from one stave to the next. That will set the natural tendencies for wood movement in opposition, resulting in a relatively warp resistant finished product.

And if you sheath the finished rudder and board in fiberglass you can use very inexpensive and easily shaped softwoods.

Cheers, Grant

You should be able to get that warp out using moisture and heat. Depending on local climate conditions where you live, you can try the old woodworker's trick of straightening it on the lawn. If it's not too late in the season put the boards out on the lawn after a heavy dew on a day with a forecast of bright sunshine. Place the concave side down. Monitor the progress as the sun heats up the day. This will gently and slowly ease the board back to flat at which time you should remove it. Don't worry if it is not dead flat, close is close enough. This really works and has saved my bacon a few times.

 Grant is right on with advice about using solid lumber.  Makes much better foils than ply. 

Some good suggestions here about unwarping your wood - I've personally tried most of them, with acceptable results.

However, if you can't get a quick fix with the sun, then just move on to finishing your boat. As long as the daggerboard fits in the slot, you will likely never, ever notice a sailing difference with that small amount of deviation in your foils. The Passagemaker is not a one-design racing dinghy - really, it will make no difference, at all, as long as they actually fit as rudder and daggerboard.

 Good luck!

Dave Gentry