> I have just finished making the first hatch cover for my Ches.17' I am not
> completely happy with it though because it doesn't quite hold the radius
> out all of the way to the edges of the cover. Where the stiffeners end the
> cover flattens out. I guess it's probably not a huge deal, because I will
> be compressing foam to creat the seal, (if there is a problem let me
> know), but is there a way to create a uniform curve on the wood?

> TIA,

> Paul

You might try making a larger hatch, with the assumption that the edges would not follow the curve, and then trimming off the less curved edges. The result should give you a hatch of the proper radius and size.

Or, instead of stiffeners, use 2 sheets of 3 mm or 4 mm or 1/8th inch plywood as a liner on the inside of your hatch. Cut these pieces of thin plywood to be 1/4 to 1/2 inch smaller on all sides than your hatch, and laminate them to the inside of the hatch, holding them in the proper curved shape until the glue sets up. These laminations should hold the curve in your hatch, and leave the edge the proper thickness to seal. Since there is a certain amount of relaxation in the curve when you unclamp it you may want to make the curve a bit greater than you really need. Since you can stack three layers of thin wood, bend, and glue them, very quickly and cheaply, trial and error may be the most effective way to determine exactly how much additional curve you have to build in.

If your boat was built over forms, you can use the form nearest your hatch location to help define the shape of the curve you want to give your hatch cover. For more or less curvature you can insert cardboard shims under the center, or at the edges, respectively to change the effective curve of the form into the curve you desire. If your boat was not built over forms, scribe a piece of cardboard to match the curve of your hull as close to the location of the hatch as you can. Transfer this to a 2x4 and cut out the curved shape with a band saw or sabre saw, to use as a mold or form. Again, you can add shims to change the effective curve if you need to. You can cut the 2x4 to give you both a male and female form. Then clamp your layers of plywood between both halves of these forms to get an even pressure over the wood as the glue sets.

Hope this helps

Paul Jacobson