[Rhodes22-list] Pipe Insulation in the Mast

[Peter Nyberg]

So, I ran my new 3-conductor wire up the mast, encased in foam pipe insulation, and this is my report on that process.

First, I want to say that when I pulled my old wires out of the mast I found that the zip-ties I used when I installed them to try to eliminate slapping were obviously too small and flimsy to do the job.  I took one look at them, shook my head, and said to myself “what was I thinking?”.  Based on this finding, and reports from other boat owners, I’m perfectly willing to believe that the zip-tie solution to the wire slapping problem can work if properly implemented.  But, by the time of this discovery I was already committed to the the pipe insulation approach.

To start at the beginning, when I arrived at the pipe insulation section of my local Home Depot, I  found that it comes in two sizes: 1/2” and 3/4”.  I chose 1/2”, which turned out to be correct.  It just fit into the channel in the IMF mast.  Four 3’ sections come in a package, so 2 packages is about the perfect amount for the job.  I ended up using 12’ of insulation above the spreaders, and about 11’ 4” below.

After getting the mast set up on a couple of saw-horses I did some disassembling. I removed the top plate, and the assembly that houses the sheaves for the halyards.  I also removed the spreader bases, and the through-bolt that attaches them to the mast.  And I removed any other hardware that had screws or bolts that projected into the mast’s wire channel.  

Next, I laid out the wire along side the mast, and made marks on the wire to help in positioning the insulation. The main focus here was that I wanted to leave a gap in the insulation at the spreaders so that it wouldn’t be in the way when it came time to reinsert the through-bolt.

The installation approach was to insert at the bottom, and pull toward the top.  Sections of insulation would be zip-tied around the wire before insertion.  After a test run with one piece of insulation, it became clear that the biggest challenge was going to be keeping the insulation in a fixed position on the wire.  

The technique that ended up meeting the challenge had multiple steps:
  
    1) select a spot on the wire about 6” below where the top end of the insulation section will be
    2) take 6 - 8 wraps of electrical tape around the wire at this point, creating a ‘bump’
    3) place a small zip-tie around the wire _above_ the electrical tape; pull tight, clip off excess
        (this creates another ‘bump’)
    4) position insulation section around wire
    5) place a zip-tie around the insulation so that it is just  _above_ the inner zip-tie and tape
    6) place a second outer zip-tie 4-6” from the bottom of the section of insulation
    7) pull both outer zip-ties as tight as you can (use pliers for a better grip); trim off excess
    8) from the top of the mast, pull 3’ of wire and insulation into the mast
    9) repeat

Note that ‘’top’ and ‘above’ means closer to the top of the mast.

Once I had the technique down, things went pretty quickly.  Now I just have to put the mast back together.

Peter Nyberg
Coventry, CT
s/v Silverheels (1988/2016)


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