CH18 hatches twist problem

Hi all. Working on my CH18 kit and building with flush hatches. I've cut out the forward hatch and originally planned to use the formers included in the kit to get the curvature of the deck. But looking at the sawed out hatch, there is a fair amount of twist. I don't think the formers, by themselves are going to take that out, but I might be wrong. Plan B is to go with the recommendation in the "tips for boatbuilders" and laminate another piece of 4 mm over a mould. Looking at the supplied hatches with the kit, both have about the same amount of twist. In fact, the piece I cut out of the doubler I am gluing to the underside of the deck has about the same amount of twist as well. My inclination is to go with the laminated 4 mm approach and flip the pieces so the twist cancels itself out (hopefully). Any suggestions much appreciated!

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RE: CH18 hatches twist problem

So you lay the cutouts and kit pieces flat on a table and one corner sticks up a little? How much pressure does it take to push the corner down? Would you say, less than the pull of the internal bungee (or whatever fastening you use) of the finished hatch? If so, I wouldn't sweat it...

RE: CH18 hatches twist problem

If you are going to double the hatch lid anyway, you can cut a few pieces of 3.4 ply to match the curve you need near the front and rear of the hatch (may be slightly different).  then fasten these to a flat piece of 3/4 ply.  glue up the two pieces and clamp them over the form.  The3/4 ply should be enough to pull the twist our and once the glue sets it should hold.

I did something like that when discovering the twist after I had glued it up.  Was able to heat the whole thing up enough to twist it and clamp and after cooling it held pretty close to what I wanted.  Enough that with the little twist cams CLC recomends with its flush hatch it pulls flat and stays dry.



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