Our Cal 31 had a deck stepped mast. The base was an aluminum casting with a raised sleeve that fit inside the mast. Water would come down inside the mast and collect in the pocket. The pocket had a drain hole but it was a little bit above the pocket "floor" where the cables went through. I drilled the cable hole oversize and put in a 1" stainless steel riser tube about 3" long. The cables passed through the tube so no water came down. The riser tube was large enough to handle the wires and the VHF antenna connector. With this I moved all the connections down inside the boat so we didn't have to make up the connections with the mast lifted.