Flirt canoe dating beyond invalidating the session
Another idea would be experimenting with hull panels pre-coated with a thin fiberglass cloth to prevent the surface from opening - again, it might take the bend or it might just crack and craze, fracturing both the coating and the 'glass. I would think you could kick your toe through a panel, where something ordinary like exterior grade white pine, 3 equal plies (Not the composed core crap Home Depot has these days) you'd have to kick multiple time to begin a bulge. The failure of the panel must have been very disappointing.
On the bright side, three of the panels did not break, so perhaps the cracked panel was due to a defect in that piece of plywood.
It would need to be something that will support the outside of the sheet material so that it doesn't flatten out as you apply the bending forces.
It would seem to me that a few ribs or frames on the inside of the hull in these areas would be a requirement to keep the curvature. Not had too much hands on with extreme ply bending, but as soon as I saw that thick center ply, I thought "Uh oh.." I have seen that kind shattered in other uses.
This device will help to keep the shape after turning around the panels and removing the lashing straps so I have access to put glass tape on the outside of the hull.
Looking good and no problems so far, but there is this almost imperceptible cracking noise. The crackle kept going and soon the damage was getting worse. I think you're seeing two issues here, perhaps three. It would be much more difficult to make up the original parts, but cutting sheets in half, rotating them 90 and scarfing them with the grain direction running around the hull would seem to make it more "possible" The second issue is moving up from a 3mm thickness to a 4mm thickness.
It really adds more work and worries but at least this aspect of the build turned out as a success.OK, I knew this spot might cause trouble again, but I think it is not that bad and I can fix it. Now there are cracks at three different places and the first crack keeps getting longer and longer. When bending the radius, thicker sheet goods will result in more compression force on the inner layer and more tensile forces on the outer layers.The third issue is perhaps is perhaps ply thickness - if it is a 4mm sheet of minimal number of plies - say 3 for 4mm marine grade ply versus 5 plies.After having built two smaller Gorewood Canoes (12' and 14') this build should be the highlight of this design family.With the insight of the two previous builds made of 3 mm poplar plywood, I decided to use 4 mm okoume ply for the 16' version, a design that underwent some refinement to get closer to my idea of a decently shaped canoe.