Well, it’s not quite that time yet (end of season),but it’s never too soon to start some preparations.
My yard requires masts be pulled for winter storage, something about those winter gales and all that windage having an effect on the jack stands. That always leaves that gaping hole in the cabin roof. I usually seal it up with a piece of plastic tarp and lots of tape. By spring the tape has either let go or bonded itself to the mast partners, neither a desirable outcome. Most years it ends up leaking water below to some degree.
This year I resolved to end that problem once and for all. I built a permanent removable mast hole cover for the boat.
I made mine from ¾” StarBoard polymer lumber, only because I had a big enough piece of scrap to complete the project. Plywood would have worked just as well, as long as it was thoroughly covered with several coats of epoxy to seal it and then painted to protect the epoxy from damaging UV rays (epoxy has little resistance to UV).
The dimensions aren’t very critical for the cover itself, as long as there is some overhang to keep rain off of the sealing area. The center locator plug is a little more critical; I guessed at the size the first time and got it a little too big. Trimmed to size, it centered the cover over the mast opening.
To completely seal out any rainwater, I covered the bottom of the top plate with a piece of 1/8” neoprene rubber. The rubber, located from a seller on Ebay, had adhesive on one side, making it easy to keep the neoprene gasket in place while installing the cover.
The top cover and locator were held together with a length of 3/8” threaded rod. The topside had a large fender washer and an acorn nut. I used an acorn nut to avoid any potential injuries from stepping on or brushing against the stub end of the threaded rod. On the bottom side, another fender washer and hex nut held the top cover, gasket and locator sandwiched together.
I left the threaded rod long until I installed it the first time and then cut it to length, leaving about 6” hanging below the mast opening into the head compartment. To hold the assembly in place, I cut an oak toggle, from 1” x 2” stock, long enough to span the opening on the bottom side of the mast partners. Another fender washer and a wing nut allowed me to tighten the cover in place, securing it against any winds or storms.
Now I’m positive I’ll get no leakage below this winter and won’t have to dynamite any tape off the outside of the cabin top come spring. A worthwhile project for less than a half-day’s work.