Max Hazelhurst wrote:

Can anyone assist me with the calculation for strip planking hull
thickness...? We are embarking on a build of a 40ft ketch.

Sounds like a large project to begin with.

I know there is Dave Gerr's formulae for determining this but have not
got his book (not available in SA). I intend exoxy glass in/out.

Well, do get that book. It is available from on-line dealers that ship
around the world. Gerr does give neat and simple formulas, but there too
many factors to cover in a newsgroup post. Get that book! I think
Herreshoff also published his scantling rules, but watch out, those were
lighter, and assumed more qualified woodworking. Chapelle might have
published scantling rules too, I don't remember. Larsson's and
Eliasson's "Principles of Yacht Design" is a good modenr work that will
tell you a lot.

I know getting these books takes time and trouble. Reading and understanding
even more so. I bet that time more than pays itself when you finally start
building. And if you get your boat to sail, you sleep much better if you
*know* that the construction is solid enough for your waters.

If you are asking that kind of questions, I recommend a year of reading, and
then a year or three of designing, before you start to chop wood... When
you get to the concrete questions, ask again. I'm sure this group can help
with many details.

Good luck with the project!

- Heikki
(already at the design stage, for a 24' schooner)