Cold Molded

[PierreP]

I'll build I cold molded catspaw (12'8) from the templates proposed for carvel planking. Should I put more longitudinal frames on the mold? Or is it suffisant to leave them to about 6 inches in between?

[Ian McColgin]

How many layers at what angles and thicknesses?

[Ian McColgin]

Oh, I was not really reading your question correctly.

I take it that this will end up more or less round bilged, not showing any planking lines.

In general with longitudinals laid across station molds, it takes more to just be strong enough to take the bending strain than it takes to get the plys to lay nice and fare. Most folk over-build the mold anyway to give plenty of attachment to get all the plys to lie down nicely.

On a dink like that, I'd start with gunnel and keel area ribbands and then just sort of fill in until you've got the bow and maybe stern pretty crowded. Then look in the midships area where the gap between longitudinals is greatest and judge if you can get your wood to lie across it nicely. If the gaps seem too large, add some cheaters.

I'm sure there's a book out there about this but really it's not hard if you use a bit too much cheap wood on the mold. Small cost compared with using too little.

G'luck

[PierreP]

I was thinking 1/8 thickness by 3 layers.

[Ian McColgin]

Sounds good.

I've only participated in one molded dink and I've watched a few larger mold jobs. In the dink we did as I described to get the longitudinals in place. As I remember the widest gaps were about 3" - 4". We rounded the edges of the battens that formed those longitudinals a bit at the bow and stern as the first diagonal layer didn't look quite fair without that touch.

It was pretty simple. Tedious. But simple.