In article ,
Old Nick wrote:

I do have a vague idea of doubling; in other words, using 12mm strips
instead of 6mm plywood, say. But I can't think of where I got this from,
and, indeed, it seems to add a lot of weight.

Unfair question. Sheathed or not? Both sides or only outside? If not
sheathed, how are you going to join the planks?

The current idea is to use polyurethane glue to join the strips.
No sheathing, probably.


Ply is very strong on its own, and if I was strip planking without
sheathing, doubling the thickness would be a minimum.

But if you sheath both sides with epoxy/glass, the whole situation
changes. The ply/strip just about only becomes a way to hold two
tensile-strong layers apart. Ply would still be stronger if damage was
done to the skin(s).

I often wonder about the strength vs. thickness vs. weight. Birch
plywood, say, is about 50% heavier than okume - is it also 50% stronger?
If a plan specifies 6mm plywood, what species is meant?


If ply of Xmm is specified, talk to the designer about how many Xmms
they would ask for to replace it.

Not all designers are alive...


Sakari Aaltonen