Lesson learned hard way
Posted: Sun Jan 10, 2021 5:41 pm
But you can learn it the easy way.
When I first built my JEM Trapper 15-38 (with which I'll never fall out of love), I had only twelve feet length of gunwales per side, inner and outer. When I made the mini decks, I extended them the required twelve inches from the stems. There were two inch gaps between the gunnels and the decks.
At the time it didn't fully occur to me that I was leaving four weak spots in my sheer line. Nice strong gunnels. Nice strong mini decks. And those two inch gaps containing only the 5 mm plywood (plus epoxy and fiberglass), a definite weak spot.
Every time I looked at them something way deep in my heart perceived something was off, but it never matured into a conscious thought until over a year of use. One day as I was inspecting the canoe after unloading from the car top, I was horrified to see the plywood in all four of those gaps starting to separate from the decks and one from the inner gunwale.
The canoe had never undergone any trauma like crashing into a shore or obstacle in water that could have done this damage. So I probably did it by lashing it too tightly onto the car top, maybe all at once or maybe over time.
So my tip for new builders is this
MAKE SURE your decks meet your gunnels.
The inner gunwales go all the way to the decks, and the outer gunnels go at least to the decks but nice if they go all the way to the stems.
The beautiful but extreme end curves of the Trapper present a challenge for the gunnels going right up to the stems but you can cheat and make separate pieces (just near the very ends)instead of trying to bend it like that.
This photo shows my adjustment to mini decks to remove the weak spots.
[https://photos.app.goo.gl/CSSZc6Ykjb9vhV6F9]
When I first built my JEM Trapper 15-38 (with which I'll never fall out of love), I had only twelve feet length of gunwales per side, inner and outer. When I made the mini decks, I extended them the required twelve inches from the stems. There were two inch gaps between the gunnels and the decks.
At the time it didn't fully occur to me that I was leaving four weak spots in my sheer line. Nice strong gunnels. Nice strong mini decks. And those two inch gaps containing only the 5 mm plywood (plus epoxy and fiberglass), a definite weak spot.
Every time I looked at them something way deep in my heart perceived something was off, but it never matured into a conscious thought until over a year of use. One day as I was inspecting the canoe after unloading from the car top, I was horrified to see the plywood in all four of those gaps starting to separate from the decks and one from the inner gunwale.
The canoe had never undergone any trauma like crashing into a shore or obstacle in water that could have done this damage. So I probably did it by lashing it too tightly onto the car top, maybe all at once or maybe over time.
So my tip for new builders is this
MAKE SURE your decks meet your gunnels.
The inner gunwales go all the way to the decks, and the outer gunnels go at least to the decks but nice if they go all the way to the stems.
The beautiful but extreme end curves of the Trapper present a challenge for the gunnels going right up to the stems but you can cheat and make separate pieces (just near the very ends)instead of trying to bend it like that.
This photo shows my adjustment to mini decks to remove the weak spots.
[https://photos.app.goo.gl/CSSZc6Ykjb9vhV6F9]