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Author Topic: Working on mast cap  (Read 158 times)

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  • Forum - Seaman
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Working on mast cap
« on: April 16, 2019, 03:55:09 PM »

I have my mast in the yard and want to do some work at the mast cap.  As you can see from the picture there is a really bad and strange hole in it.  The wire cable going through it is a coax to the VHF antenna.  It is almost completely severed.  I installed an anchor light there on a bracket that you cannot see.  The PO had no anchor light.  I bought new coax for the antenna and new cable for the anchor light that I want to run through the existing PVC conduit. 

I have a few questions:

1.  How  would you recommend I cover up or fill in that ugly hole?  I thought about finding some aluminum to either weld or fifty-two-hundred over it.  But I don't know how to weld and I don't know where I'd find a thick piece of aluminum the right size.

2. Should I use that better looking hole to run both the coax and cable for the light, and install a grommet in it?  And if I do that should I put any kind of sealant around the wires?  Or should each cable have its own hole?

3.  Would it be better to drill a new hole(s) for the two cables that is actually on the side of the mast that the conduit is on?  What exists now is a hole through in inside of the mast cap allowing the wires to go from the starboard side to the port side of the mast (the exit holes are on the port side).  I have no idea why they didn't just drill the hole through the starboard where the conduit is attached.



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Re: Working on mast cap
« Reply #1 on: April 16, 2019, 04:54:01 PM »

Perhaps you could drill a hole that removes the problem area and install a rubber plug. Then grommet the hole for the wires and seal. We use big rubber plugs on old police cars when taking all the lights and antennas off.
1987 mk1 a work in progress #618

Gregory M

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Re: Working on mast cap
« Reply #2 on: April 16, 2019, 08:46:02 PM »

Gregory, "Luna Rossa", #1063, 1990, Mk 1.5, fin keel. Universal M 35,  Rocna 15,
Penetanguishene ON.


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Re: Working on mast cap
« Reply #3 on: April 17, 2019, 06:11:45 AM »

Chris a couple thoughts come to my mind.

I ran both mine thru the side, less likely to get water intrusion.

Though not my preference, keeping them thru the top would probably be the easiest for you, using 1 or 2 pass throughs.

If you do cover the top it doesn’t need to be really heavy aluminum, you just want to put window dressing over what’s there.  You can get many oddball materials thru McMaster Carr. Probably heavy gauge alum.

You might be able to get a LARGE.”well nut” to plug the ugly hole if you redrill it.

Alternatively a rubber cork, drill a hole thru it for a stainless screw to tighten it once inserted (sorta like a plastic wall anchor) experiment with the size screw. A plug w/a shoulder like a well nut would be best but unsure if you can find that at

Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain


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Re: Working on mast cap
« Reply #4 on: April 17, 2019, 08:16:22 AM »


      That black hole with the three screw holes is probably where the original anchor light was, looks like PO broke a couple of screws trying to remove the anchor light. The other butchered hole looks like it was done by a guy sitting in a boatswains chair with a drill who just kept drilling holes until the opening was large enough for whatever needed to be passed through it. I wouldn't be overly concerned about the cosmetics, the only way anyone can see it is to take a trip up the mast in a boatswains chair. I'd just run or install whatever you need, then seal any holes that remain, it doesn't have to be an exotic sealer, Henry's roof patch would work fine.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273


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Re: Working on mast cap
« Reply #5 on: April 18, 2019, 02:48:04 PM »

Just redid mine.
Rob Fowler,1989 C34 #889 Tall/Wing, M25XP - No Worries, Coronado, CA

I'd rather be in a boat with a drink on the rocks, than in the drink with a boat on the rocks.
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