If you want to avoid an unstep of the mast I would check out pass-thru connectors. I personally have no experience with them but Blue Sea systems builds one called a Cable Clam, along with other vendors I found on Defender.com. (no affiliation to Blue Sea or Defender)
Here are the comments from BlueSea:
Cable ClamsDrilling a hole to pass an antenna cable through a rooftop or transom can allow water to pass through if not properly sealed. CableClams provide a waterproof pass-through for antenna, transducer, and other cables without removal of the factory installed cable connector. Blue Sea Systems now offers updated versions of these popular products including the addition of five new models. New models include a side entry clam as well as versions with 316 stainless steel caps and pre-drilled rubber inserts.
Cable Clam
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