A couple of years ago, while sailing in Galveston Bay, we ran across a yellow object in the water. Since we had just talked about a "man overboard" procedure, we decided to rescue this object. It turned out to be a starboard light used on a barge. Obviously, the magnets had come loose, and the unit fell into the bay. This was perfect. The battery enclosure was removed, and the building began.
In order to have the wiring come out the top of the mast, the mast was not built according to the plans. The top seven inches were built up with scrap wood to give it more strength. Two circles were then cut from scrap plywood, one 4 1/2 inches and the other 4 inches in diameter. These were laminated together and a 1 inch hole drilled in the center. This was then laminated to the top of the mast. To attach the light to the mast, a PVC drain cap was painted black and bolted to the light. This fits perfectly over the upper circle and will be secured with screws.
The PVC cap sides are taller than the base it sits on, leaving an open space for the wiring and connecters. This will enable us to remove the light and store the mast inside the boat when not in use.
An antenna will be mounted on top of the light, but I haven't decided the best way to do that. I'm sure that epoxy will be involved. And, the internal workings of the light are not finished yet. I will post them when they are finished.
I am very happy with the masthead and light. Hopefully, it works as good as it looks.