"Pete" wrote in message
...
Hi all, I'm newbie here; I'm about to start on a 34' sailboat using
cedar strip planking core/glass fibre.

between Red Cedar that comes from Canada and Western Red Cedar.

I doubt there's any difference. One way to tell if it is WRC is to measure
the density, which IIRC is about 20-23 pounds/cubic foot.

Am I just going over the top with this, or is it really a problem? My
gut feel as a joiner is that once the stuff is encapsulated it stays
stable and I reckon 16/17% is fine. The only problem I have ever had
with wood is when it moves - and it only moves when the mc changes
(I'm talking of shrinkage here not flex although I know drier wood is
stiffer, or rather harder).

This could be a risk. If you put it in at 9% and it gradually changes
to 16% there will be movement. Whether it causes any problems is
another question. Glenn Ashmore, who is building a 45' strip
planked/glass sheathed boat (www.rutuonline.com, better go read it!)
didn't have any problems until he glassed the outside of the
boat. The hull then started moving all over the place until he sealed
the inside.

I have also been told to temporarily fix the strips to the molds with
stainless steel nails,

Nothing temporary deserves stainless, or even galvanized.

One more question for now; I have seen tongue & groove and bead & cove
strip planking for sale; I can machine this myself, but are there
significant advantages over square section when using epoxy?

Tongue and groove can be fast, but I don't think all the grooves could
ever be fully filled with epoxy. The gaps in the grooves will wick whatever
moisture is present, and it would be up to you whether you think it will
be a problem. It certainly can be for blasa cored boats. The bead and
cove has a couple of advantages: You use less epoxy, and there is more
surface to glue (not that epoxy needs the help). Disadvantage is the
extra machining.

Good Luck!

Matt