scribing the keel

[Noklin]

Per the plans, the keel is to be scribed at the aft end to fit the hull curve up to the point it reaches the minimum thickness line, in the case of the CS20 this is 1 inch. Per the plans, the keel is 3 inches at the aft end, tapering down to 1 inch approximately 6 foot forward and maintaining 1 inch to the forward end.

This requires that the forward section of the keel be bent down to mate with the hull curve. Screws are normally required to hold the keel in place until the epoxy sets. Screws require holes to be drilled in the keel batten and someone working under the boat to install the screws up through the batten, the bottom of the hull and into the keel.

I was wondering why the keel could not be scribed all the way forward. Then cut to match the 3 inches aft tapering to 1 inch as per the plans.

Advantages:

[Tom Lathrop]

I'm less than 100% sure of your plan but if it is like I think, the disadvantage is mainly that the forward part of the keel would then be cross grain and very weak.

[Hirilonde]

And it would require a really wide board to begin with, producing more scrap.

[tom151]

And it would require a really wide board to begin with, producing more scrap.

Try an experiment with a (relatively) thin batten... see if it can be made to smoothly follow the curve of the keel line. Use props from the floor or cradle and wedged up against the batten -- not too much pressure. It might take a few tries to find the correct thickness of the batten but when that seems to work (not too much pressure) then you'll be able to actually  laminate a keel in place - adding another batten every day till you get the keel built up to the depth you want. you may want to cut one long wedge shaped piece for the aft-most region to build up a lot of thickness there before you start adding strips.

Take full advantage of the gap-filling properties of extended epoxy - it allows you to build lots of parts without having to have close-fitting tolerances in the wooden parts.

Cheers,

TomH

[Hirilonde]

There is a lot of strength in a laminated curve.  And all the grain is going the right way.  More work doing it TomH's way, but the result will be fantastic.  The added strength characteristics may not be necessary, but they wouldn't hurt any feither.

[tom151]

This requires that the forward section of the keel be bent down to mate with the hull curve. Screws are normally required to hold the keel in place until the epoxy sets. Screws require holes to be drilled in the keel batten and someone working under the boat to install the screws up through the batten, the bottom of the hull and into the keel.

Apologies,

Upon reading your original post one more time, I see that I had the picture that you boat was already right-side-up - hence the suggestion to place props from the floor to hold the keel strips in place while being laminated.

Since it seems now that you're upside down, it's much simpler. Just use the epoxy-builder's friend, the drywall screw, to temporarily hold the laminating strips in place till the thickened epoxy goes off - then remove them as soon as possible. Use your epoxy syringe to then fill the holes (keeps the air bubbles to a minimum if you fill the hole from the bottom up by inserting the tip all the way to the bottom of the hole and inject epoxy slowly as you withdraw the syringe).

Cheers,