Drilling/screwing through the cabin roof?

snal

I've shaped a piece of 1x1 alminum "T" stock to fit the curve of the cabin roof just above the door. This will minimize water roll-off from the roof, and give me something to secure the snaps for my future canvas top.
I can screw directly into the top of the core of the rear cabin wall, and install with a bead of 5200 under the aluminum. Should I also pre drill the holes (oversized) and fill with epoxy, or is this overkill?

thataway · Posted: Fri Aug 17, 2007 7:02 pm Post subject:

The usual way of installing canvas is to put a vinyl awning rail screwed into the slightly elevated area of the aft cabin top. The awning rail is the way which almost all boat aft canvas tops are secrued to the boat cabin top. I used 4200 under the awning rail with SS screws on this. I understand that some of the 22's tops are not cored. If the top is cored it would be best to drill out the hole first, then fill with epoxy and redrill. Before putting any screw into a gel coated surface, be sure and use either a larger size drill bit, or preferably a counter sink bit to cut back the gel coat, which is more brittle than the glass laminate and will splinter or pop up and crack.

5200 is more perment. Be sure and use an aluminum alloy which will have minimal corrosion. Also the SS screws and aluminum will react, so I would prefer to have a small abount of 4200 or 5200 under the screw. Also the aft cabin top is curved, and not sure how flexiable the aluniumum tubing is. The vinly awning rail along with velcro with the zipper which attatches the canvas to the awning "rope" makes this attatchment absolutely water proof.

snal · Posted: Fri Aug 17, 2007 7:26 pm Post subject:

Thanks Bob. My roof is not cored, the core that I plan to screw into is actually the top of the aft cabin wall where it meets the roof. This area is directly under a crossmember in the framework that I now have mounted to support the canvas. The aluminum that I will use is a "T" shape rather than tubing, mounted as an inverted "T". I already have it shaped to match the curve of the roof. The aluminum is 6061 T-6, not the best for a marine environment, but also not the worst, and I've used it on many freshwater boats.
I "might" opt for a piece of Lexan to fill this area between the cabin roof and the crossmember of my cockpit roof frame (roughly 9"), just because it would simplify the canvas construction, which I plan to do myself.