Michael Haas, #78, Figment
For those that haven't been following along, the perimeters of #78's chainplate-bearing bulkheads were surveyed to be saturated, and during removal found to be amazingly rotted. The task now at hand is to install new 3/4" fir marine ply bulkheads........
A brief synopsis:
Saturday was rainy, so I spent most of it on the tender, and as far as this larger project was concerned, I merely dry-fit the bulkheads in place, expecting to find high spots that needed grinding. when I found none, I left. Sunday got off to a later start than expected (foolish expectations!) and working alone I was only able to make 75% of the tabbing on the starboard bulkhead. Monday again got off to a late start, but with the help of a buddy who also had the day off, everything was completed with the exception of the knee for the port aft lower shroud, which I'd left sitting pretty back home on the workbench. Cutless bearing? what's that?
Lessons the next guy won't have to learn the hard way:
1) The notion of using tapered foam to cushion the bulkheads to the hull and make instant fillets was folly. I'm sure it's a great timesaver when cutting bulkheads to a well-fit template in new construction, but for me it just turned into a huge pain. My tolerances were actually better than I expected, something in the +/- 1/8" range, but this was still too imprecise. The foam either wouldn't fit, or would fit too losely to hold itself in place. Perhaps if a more compressible foam had been used it would have been easier. I wound up making 80% of my fillets with silica-thickened epoxy.
1a) +/- 1/8" is not too shabby when fitting to the irregularities of a 43year old hull. I attribute this close tolerance to my process of making cardboard scribe templates of the existing bulkheads prior to demolition, and using these to make "scratch" templates of luan plywood, which were fitted and re-scribed to the hull after the existing bulkheads had been removed. Template twice, cut once. Or something like that.
2) As the mockup taught me, the heavy tape laid very easily once wet-out, but wetting out was a challenge unto itself. My limited progress on sunday was due to the fact that I was spending at least 2/3 of my time mixing resin and wetting cloth. Having a helper today made all the difference in the world. Ideally, it's a three-person team effort. One constantly mixing cups of epoxy, one measuring, cutting and wetting cloth, and the third laying the tabbing and rolling bubbles.
3) I grossly underestimated the amount of epoxy required to wet out cloth of this weight. I had to run for more goo TWICE. Luckily, a Woodcraft store 20minutes away carries a small supply of System Three products. Total consumption on this project will exceed two GALLONS of resin and a gallon of hardener.
3a) I also grossly underestimated the number of disposable gloves I'd go through. 120+ I consider this $15 well spent, given lesson #4...
4) Don't kid yourself about this being a less-than-messy job. You WILL stick to everything, and everything WILL stick to you. Don't be bashful about changing gloves every time you begin a new task. Wear a longsleeved shirt and pants that you will throw away. In retrospect, a shower cap would've been a good idea too.
5) Do what you can ahead of time to get all of your substrate to one even color tone. I wasted a lot of time in the early pieces obsessing over what I thought to be air pockets, but which later I realized were just whitish patches of the hull fiberglass.
6) Yes, handling a 24" length of wet laminate through the v-berth storage hatches is as difficult as you think it is. You will invent new words, and you will twist in ways you'll only feel later that night.
But with a few hours of perspective on it now, it's a worthwhile project. I consider this new installation to be near bulletproof. With a combined 60ounces of modern fiber set in epoxy binding these new epoxy-sealed bulkheads in place, I feel perfectly comfortable stating that it's Stronger Than New. If we encounter forces strong enough to part that bond...... well, screw it, the stick deserves to come down.
Also, if I hadn't been educated enough on the topic of Sealing All Deck Penetrations, this little ditty has driven it home with gusto. ALL of the rot found in the bulkheads was due to water intrusion from the chainplate penetrations. It had initially been speculated that the rot was due to the partial-sinking that #78 experienced under previous ownership, but I discount this entirely. The lower portions of the bulkheads, while saturated, had not yet begun to rot.
I was pretty anxious going into this. It feels wonderful to have it behind me. Now to finish putting the rest of the boat back together.....