I don't know about using it covered with vinyl? but it is the ticket for
what you want. It good for stingers, bulkheads, floors and other boat parts
that need strength. I have used it in building consoles, leaning post and
replaced old floors in fpr boats where the original untreated ply rotted. It
is very strong but also heavy. As far as it warping as others have said,
you will find that the "kiln dried after treatment" designation is not prone
to those problems and behaves it's self. I have bought it at local lumber
yards but only a few ,if any, will have it kiln dried. There is an XL grade
(basically what I used) that is used by a number manufacturers of quality
small runabouts like Glacier Bay catamarans for structural thing like
stringers. In the cases I know of, it is encapsulated with frp lay-up. For
your floors the encapsulation might be something to consider but just
sealing would be a lot easier and lighter. If your boat is like most fishing
boats, the floor boards will get soaked from time to time and it will become
heavy and probably end up warping if you dont seal or encapsulate the wood.
Since you are lining boat, you may want to fit and fasten these floor boards
so they are removable as nasty stuff will get under them and accumulate
there. I would also suggest that you seal the wood top and bottom (and
edges) with something like clear epoxy resin and then paint the top and
apply some antiskid material.
Do a Goggle search for XL plywood and read up.
--
Ron White
Boat building web address is
www.concentric.net/~knotreel