It’s been a very busy two weeks. The weather gods suck…windiest winter ever, and what’s the deal with two snow storms in March, including one just before the Cherry Blossom Festival???
Oh, also, if anybody thinks up how to produce 20cfm of air at 90psi with only 120VAC on a 20 amp breaker in the boatyard that services 16 power pedestals, drop me a line. 😉
The fairing work continues on the cabin top, though you wouldn’t know it by looking at the end-of-the-day pix. We’re also taking a different approach to the cabin top-to-deck joint than Chris Craft did.
Back at the Chris Craft factory in 1969, 1″ x 4″ mahogany boards were bolted to the deck structure all the way around the opening that will become the salon and galley. The FRP cabin top was then craned onto the deck, with the bottom edge fitting tightly to the mahogany on the inside. Screws spaced 8″ apart secure the bottom edge of the cabin top to the mahogany. Large radius quarter-round mahogany was then screwed in place over the seam, with bedding compound to keep things dry.
It was a good approach except for a couple of problems that arise over decades of use: The coating on the wood fails eventually, so there’s a maintenance premium without as associated payoff. The bedding compound eventually gives up, usually in just a spot or two. This allows small amounts of water to leak in and go unnoticed, rotting out whatever mahogany it comes into contact with without a telltale drip to alert the owner.
So our approach has been to cover cabin top-to-deck joint seam with 1708 biaxial fiberglass, which we’ll cover with very nice, water-shedding fillets.
This shot is from when we first got the boat, and shows the port side deck looking aft at the transition from aluminum decks to teak. The quarter round is broken from where the teak deck buckled, but you get an idea of how it worked. Also, note the paint has mostly fallen off the wood. It doesn’t matter how you do it, paint will not stick to exterior wood and stay there like it will to fiberglass or metal.
I think there’s a better, more modern way.
As when we fiberglassed the cabin top, bowseat and dashboard, we use US Composites 635 epoxy for the FRP layup (with just a touch of cabosil to improve adhesion between the ‘glass and aluminum) and then hot coat it while it’s still tacky with fairing compound made of 635 epoxy, 3M microbubbles, and cabosil.
It’s amazing how much fairing compound you put on compared to what remains in the end. The windshield base that had been previously repaired is now much stronger and straighter than it was before.
We’re blocking the filler to sharp lines at the edges, which made low spots and wiggles very apparent. Before priming, we’ll sand the sharp edges down to a nice radius.
That’s a whole weekend worth of sanding and fiberglassing, but she just doesn’t look much different than when we started. We really are heading into the painting home-stretch, though.