Okoume is very flexible and needs to be encapsulated. It is used by the
Outer Banks boatbuilders when they need to produce the pronounced "Carolina flare" hulls. Sepale and Maranti tropical
wood marine plywood is very durable. Some builders in NC still use Douglas fir as it bends.
Pine is a soft, knotty
wood. Not good.
I spoke with Scott Roberts of Roberts Plywood (a large northeast supplier to
boat builders) regarding the glue issue. He said it is like answering "is there a difference between car brand quality or the quality of different producers of chicken? Would a good quality
marine plywood use the same glue as a bad quality exterior plywood, no."
The tropical woods have less knots and a tighter grain. There are fewer voids,
repairs, plugs, defects and patches in the plywood.
When
water gets in a void and the temperature changes the trapped
water expands and delaminates the plywood plies. The glue helps keep the plies from delaminating.
He said to look for the British stamp 1088 to be pretty sure you are getting good quality marine plywood with few voids, lots of plies of the same species without lots of
interior repairs or patches.
Also regarding the glue, a lot of plywood comes from
China. And you know how reliable they are about quality. They even falsely stamped a bunch of old
flooring as being low formaldehyde and sent it to
Lumber Liquidators- and they are now being sued.