To close the loop:
Maiden voyage of the Sawyer carbon copy 1 had its challenges. This was in May of 2025.
Upon arrival at our launch site (Big Moose Lake, ADK's) I noticed a problem.
Yeah, that was my reaction too! WTF is that seat??? In retrospect, it likely shook loose a mile from home. This was just the first indicator of a series of issues.
In my 40 years working in Research, we used to say that we learn more from our failures than from our successes.
Ok, I learned an awful lot...
Please take a moment to watch this video link below, maybe even watch it a few times, be sure you have sufficient sound
Yup, those unmistakable sounds of delamination.
We did finish the trip with that hull, not much choice unless we wanted to add 10 miles of bushwhacking.
I put the boat away and didn't look at it again until a month ago.
When I finally got around to moving the boat to my garage, I found that the remaining seat was barely attached.
Quick review, hull layup from outside to inside was as follows:
6 ox E glass
6 oz E glass
5,8 oz carbon
1/8" H80 Divinycell
6 oz E glass
This hull was built with all polyester resin, strictly a cost decision. Apparently, we did a terrible job of attaching the 1/8" H80 foam stiffener to the inside of the hull. At this point, I can't remember if we washed the interior to be sure there was no Partal left on the INSIDE of the carbon layer or not. More on that later.
Also, we did not use the finishing resin (with wax) when applying the inner layer of glass. (In another thread, I mistakenly stated that layer was carbon, it was not. It's 6 oz E glass)
As a result, the surface of the final interior layer remained ever so slightly tacky, and would likely remain so for infinity.
So I washed the tacky interior with acetone, removing that eternally tacky surface. Next, I set about removing the remaining seat cleats.
2 of them popped right off, clearly not adhered well at all. 1 cleat was a bit more difficult to remove, and while prying it off, I noticed that the inner layer of glass was separating from the carbon layer, a few sq in worth. I cut that delaminated piece away with a scalpel. The carbon layer under that was extremely smooth, fully wet out and fully cured. (this was the INNER most layer when we were laminating the hull on the plug)
So what went wrong? It seems that the foam to carbon AND the glass to carbon bond was inconsistent. Or is it just a bad idea to expect polyester resin to bond to fully cured polyester resin?
In any case, this is the final build with polyester resin. ALL future builds will be epoxy only.
In an effort to not throw away the hull, I came up with a salvage plan,
The interior now being completely tack free, I decided to add more stiffening on the inside of the hull.
Years ago, I bought a large amount of 3/8" H80 foam, all off cuts from someone else's production runs. This Divinycel was scrim cut from both surfaces to make it more compliant. even so, the 3/8" foam didn't really want to conform, but I imposed my will on it.
I used some Cabosil thickened RAKA epoxy resin to attach the 6-1/2" wide pieces of foam, then added Cabosil thickened epoxy fillets, and finally beveled the foam to allow better conformance of the subsequent 5.8 oz layer of carbon.
And
It seems that I may have salvaged this thing, I'llknow for sure once I get seats back in and take it for a test run.
Speaking of seats, I made a replacement Dodd seat from mahogany, same dimensions as the other seat.
I bought some 5/4" thick cedar for cleats. I plan to make the cleats about 12" long, epoxied to the hull, wrapped with 6 oz E glass, AND install a couple screws through the hull into the cleats. Sort of a belt, suspenders and rope approach.
Hopefully, this update might save some of you from traveling down the same errant path that I did...
