This was done as a way to simplify raising and lowering the mast at beginning and end of the season. It is simply a chromed brass kitchen sink J trap turned upside-down and pushed into a 2 bronze through-hull mounted in the deck. Mast wiring runs up and back down into the interior where it mates up to corresponding plugs. The RG-8 antenna cable makes a very efficient unbroken run from the masthead all the way back to the radio at the aft bulkhead by the companionway. Ive never had trouble with sea water coming in.Visable to the right in the photo is the lower end of the Garhauer solid boom vang and the lower mount I had them make up.