JEM Watercraft

I've just marked out the ply for a 14ft Sassafras canoe and my question is, am I mad just using WBP grade ply? I've got a good few sheets of 4mm WBP left over from a renovation job I did and I was going to use four sheets for the canoe. I know Marine grade would be better but this being my first canoe I thought, you know, waste not and all that. I was also going to fiberglass the whole outside of the canoe twice instead just the bottom and the seams. This is wrecking my head so any advice would be great. Thanks. john

you mean Sasquatch?

WBP grade ply is made to be "weather and boil proof". So by that definition, it should be ok for building small craft.

However, voids in the middle of the ply and/or poor bonding between the layers are what will cause headaches.

If that's what you have on hand and want to see how good it is, here's what I'd do:

Trace and cut out the panels on sheet 1 and then give the panel edges a thorough inspection. Look for voids or poor bonding. In a dark room, turn on a flash light and press it again the ply and look on the opposite side. See if any large voids show through.

If all look well, you're probably good to go. Give each following panel this type of inspection.

If you find voids and you start feeling uneasy, hang onto to those panels and use them as patterns for some better quality stuff.

Marine grade BS1088 ply is the safest way to go.

John, after you inspect your plywood, I hope you have one piece that is not satisfactory for making boats. You're going to need a workbench upon which to build your boat.