: I have built two Pygmy boats (AT & Osprey) and a Point Bennett
: using Okoume plywood and a Great Auk stripper. I plan on doing
: another s&g kayak this winter from plans. I know Okoume is
: recommended because it does not have voids but it is expensive
: and shipping is very expensive since I can't get any in upstate
: NY or in SC where we go in the winter. I would like to use some
: other plywood that is readily available in the big box stores or
: at lumber yards. I have heard that some people use luan door
: skins or something similar. Has anyone used some other plywood
: and what would you recommend? Type of plywood and thickness?

: Charles Robinson

Charles:
Like you, I'd probably prefer to use marine-grade plywood if the cost and availability 'made sense' for each project.
After all, with all that labour and expense for epoxy, it doesn't always make savings on plywood worthwhile.
I've built a 4' x 8' 'roof rack' for the car (2x4 frame to ride on existing roof rack) to transport thin plywood at highway speeds on a couple of occasions, to get around the local availability issue.
I've built a few projects with door skins (~1/8" ply).
One was a 'quick' nesting dinghy that I built in 1998, which got quite a lot of fairly rough use on my sailboat, and apparently is still going strong today. (I expected to replace it with something 'better' in a couple of years, but it just kept 'keepin on'.
Another was a 'Greenland-style' boat I built this year, an ArcticTern14 variant with a stripped deck.
Both were glassed both sides and painted, and used mostly 'leftover' glass and epoxy from other projects.
They both turned out fine, though my standards may be low. ;-)

The main problem I've found with (luan-type) doorskins isn't voids, but delamination and splintered veneers, usually at the sheet edges.
I definitely would never consider using any of the cheap 'domestic' fir or birch plywoods that I find in the box stores and local lumberyards, as they are rife with voids. One frustrating experience with HD 'birch plywood' building some speaker boxes taught me that lesson.