Coax
Here's how I did mine on TASHTEGO. Measure the diameter of your coax then go to the hardware store and buy a drill bit the same size. Its a good idea to cut a piece of coax a couple of inches long and take it to the store to get exactly the right size bit. Go to your marine outfitter and buy a Cable Clam, the smaller size. Drill a hole through the center of the rubber center of the cable clam with the new drill bit (an old bit will not cut well and will leave a jagged hole in the rubber). A little soapy water will help with the drilling. If you use soapy water, use a cordless drill. A 110 Volt drill and water don't mix. Putting the rubber in the freezer for an hour or two before you drill will make the drilling easier too. Drill a hole through the cabin top on the starboard side near the mast with the next larger size drill bit. Put a piece of masking tape across the bottom of the hole inside the cabin to prevent drips. Mix up a little penetrating epoxy (small kits are available from West Marine and others) and saturate the inside of the hole in the cabin top. When the epoxy has set up remove the tape and run the drill bit through again if necessary. Now put the top of the cable clam on the coax facing down, then put the rubber on the coax. Once again use soapy water as a lubricant. Note that the rubber is tapered and the smaller side goes down. Put the base of the cable clam on then the rubber gasket. Feed the coax down through the cabin top. If your coax is already run, reverse the procedure. Pull the coax up through the hole then put the gasket, the base, the rubber and the top of the cable clam on. Now assemble the cable clam on the top of the cabin top, go below and route the coax to the VHF. Cut a 3" circle of 1/8" (0.125") aluminum (your local rigger probably has some scrap or try <www.onlinemetals.com>) with a hole in the center and put a grommet in the hole. A 3" hole saw will do the job nicely but you will have to smooth the edges and enlarge the center hole. Make the center hole big enough to take a grommet large enough for your coax but no larger. Then cut a smaller (1 1/2") hole in the flat side of the mast around 6 inches above the base. Drill two holes in the top and bottom of the plate and drill and tap two matching holes in the mast and screw the plate onto the mast over the hole. Use SS round or pan head machine screws and put TefGel or the equivalent on them to prevent corrosion and galling. Make sure the hole in the mast is large enough to pass a coax connector. Inside the mast the coax comes down from the antenna to a connector. The coax coming up from the cabin top goes through the cable clam then into the mast through the hole with the grommet. Inside the mast it also has a connector and a coupler. When I need to pull the mast I remove the circular aluminum plate and undo the connector inside the mast. This disconnects the coax leaving the cable clam and 3" disk on deck. My main lighting connector is on the port side and functions in exactly the same way but with a larger cable and cable clam. This set up is waterproof and allows for an easy disconnect when unstepping the mast.
