After installing the “easier” of the two hatches in the saloon, it was time to turn my attention the problem hatch in the v-berth. The wood base was all cleaned up after hours of scraping, sanding, re-gluing, drilling out rusted fasteners and installing new ones, filling voids, and so on. Once ready to go I covered the bottom with butyl tape and screwed it down. The clamps were instrumental in applying sufficient pressure to press the butyl down without putting too much pressure on the threads of the fasteners going into the fiberglass and stripping everything out. I went back and did this to the forward hatch as well after letting the butyl settle for a day.
I then sanded it down again and countersunk the areas in which the hatch fasteners would penetrate the wood. This adds a secondary layer of water tight protection as the sealant will “pool” into the countersunk hole and form around the threads of the fastener.
I put little snakes of butyl tape around each of the heads of the screws for the hatch and used Dow Corning 795 on the bottom of the hatch base. The Dow Corning is an excellent sealant that I covered in when talking about glazing in previous posts but it also works very well for areas that will flex. Since wood flexes and I wanted something more fluid than butyl to fill all of the gaps and screw holes in the wood I went with DC795.
Above you can see the layers of work. First we have the newly epoxied and faired fiberglass base attached to the headliner. Then you can see the wood with sealant on both top and bottom and finally the aluminum hatch base all clamped down together.
Here is a picture of the almost finished product:
And a picture of both the hatches together: