Catspaw dinghy

[Zaynab]

I just bought plans from WoodenBoat for a catspaw dinghy and have two questions. Can I use lapstrake planking instead of carvel plank as in plan? I understand that lapstrake could be thinner (maybe 3/8" rather than 1/2" as in plan) and this could affect the rabbit depyh in keel ans stem. Would redwood be good for planking stock? I have some CVG redwood and would like to use it for this project. Does anyone have any suggestions or reponse to these questions?

[Thad]

The Catspaw is Joel White's iteration of Nat Herreshoff's Columbia Lifeboat Model which the Herreshoff's built from 9' to 20' lapstrake.

[johngsandusky]

Welcome aboard!
There is a small booklet on Building the Herreshoff Dinghy which can guide you in building a lapstrake version.
I think redwood may be too soft for thin planking. Maybe someone here has tried it.
Good luck, keep us posted.

[Marty J]

It certainly wouldn't be the first lapstrake Cat's Paw. I'm not sure if or how the scantlings would be affected if your plans are for carvel.

[jonesmatt1957]

Going to be a great boat. Post pictures, please.

[TerryLL]

I had a friend in Alaska who built a Catspaw riveted lap in WRC. No problem.

You should buy this book, available from WB.

Screen Shot 2023-02-08 at 10.46.08 AM.jpg

[robm]

Redwood is harder, stronger, and stiffer than WRC, and much harder, stronger, and stiffer than eastern white cedar, so it should be fine for planking.

[ptscho]

Yes, can do lapstrake. I built the Herreshoff Columbia dinghy which is the lapstrake version of the catspaw (and a foot shorter). Herreshoff planking is 1/4".

[Bruce Brown]

glued lap (with plywood) will allow single handed building while traditional lap with rivets will require two people (one inside the mold or inside the boat). Carbon footprint is better, though, I reckon.

[Sailor]

Mu catspaw build has been barely moving for close to 10 years now. Life gets in the way sometimes. Good luck, I have enjoyed the project so far and look forward to continuing. Hope you have as much fun with yours as I have so far with mine.
Cheers,
Daniel

[Paul356]

Even as early as 1932, there were warnings that the properties of redwood could vary greatly even within a single old-growth tree, and that second growth redwood could be a much different animal. Some parts of a tree are a lot more decay resistant than other. I'd submit it's hard to know just what properties your redwood exhibits without careful study. We had some redwood show up at the shop that had 100 growth rings in less than 2" (i.e., the real thing). But there is plenty of "redwood" on sale now that is brittle, punky, soft, whatever. Note also reference in the new pamphlet to turning black if exposed long term to moisture. In short, know your wood before you commit to building with it.

1932 Reference pamphlet: https://naldc.nal.usda.gov/download/...tility%20value.

More recent trade group reference:
https://homeguides.sfgate.com/redwoo...ics-99416.html