Those deck seals look sweet -- unlike my radar
cable, my VHF
cable exits the mast above deck, and then goes through a similar device.
But as I sit here thinking about it, it occurs to me that when I first removed the cabin headliner to investigate the leak, I pulled the slack in the radar
cable into the cabin. I'm thinking that "slack" might have actually been a drip loop. so while I solved one problem (by removing the caulk in the mast drain hole), I might have caused another (by removing the drip loop). Hopefully, I can put the drip loop back in (I can certainly push the slack back in the mast, but it may take some work to form a loop).
This also makes sense in light of the fact that there is absolutely no evidence that this leak is long standing -- no stains, no deterioration, nothing, even though this boat has been weathering Pacific Northwest winters for at least 15 years.
One good thing about all this -- I was able to identify that the plywood coring forming the deck penetration is rough and raw, and needs to be smoothed and epoxy