mast hole

[tlochhaas]

Anyone know of an authority for how big a hole it is safe to drill in a
Vega mast without potentially causing weakening?

I'm installing a JVC 1000 radar unit this spring and need advice. In an
earlier posting I inquired about routing the cable and learned that some
people have brought a radome cable down the outside of the mast in a
conduit and then through a new deck hole. I considered this but for
various reasons would prefer to run it through the mast itself. I walked
around my local boatyard and saw about 25 radar units all wired through
the mast, but it's impossible to tell the size of the holes they drilled
because the hole always has a plug-like thing surrounding the cable
where it enters the hole (don't know what that thing is called). Anyway,
I'd have to drill a one-inch-diameter hole to get the radome plug
through, and that seems like a lot. I investigated cutting the cable
(which itself is only 3/8 inch dia.) and having a connector made, but
that raises a whole new set of complications for the 14 or so wires
inside, and I've been advised against it. I also opened the radome to
see if I could easily disconnect the cable on that side for
installation, but that doesn't look like a job for an electrical amateur
like me. So I'm contemplating drilling the 1-inch hole. It would be
perhaps 10-12 feet above deck, well beneath the spreaders (which I
believe is a higher-stress area). None of my various books gives any
indication whether a hole that size would weaken the mast. I know that
some brands of mast steps use two holes of about 1/4 inch not far apart
on a horizontal plane, and I've never heard of anyone worrying about
that, but this would be about twice the size. So, anyone have any
information? Thanks!

Tom

 

[tjelle1946]

Tom--the smaller hole the better. I read that most people have the cord plug removed and installed after the cable is pulled so as to use the smallest hole possible. See if you cna find a fine wire tech to do the plug for you as you want it doen right. A one" hole may weaken your mast quite a bit. jorgen

 

[Vega1447]

Tom, can you disconnect the cable from the radome and run that end up through the mast from the
bottom?
Then you would only have to drill/cut an elongated 7/16ths hole in the mast. An enalarged hole
would also accomodate some protection from mast chafe with that cable.
Another trick to prevent internal noise from the slapping cable is the run small spectra or wire
with the cable. The wire/spectra would have an eye to fasten to the mast externally, and be
taped to the cable every 6" or so. Then take up on the wire with reasonable tension at the
bottom and secure it so the extra tension would prevent internal mast slapping.
-Pete

 

[zaza_sese]

Hi Tom.
I agree that the smallest the better, so I'd let the cable go through the
mast, just place a rubber washer to prevent the cable from being cut. Also,
the part of the mast you're going to drill is rather stressed. There are two
things that could help.
1 - If you tell me the shape of the section of the mast I can tell you which
is(are) the most convenient side(s) to drill, i.e. the side which is
normally less stressed. With the help of a metal bracket, you set up your
radar in the right position around the mast.
2 - The part of the bracket which stays in contact with the mast, can
eventually help to compensate for the loss, it it's properly designed, as a
strengthening element. In general, a number of small holes provoke less
damage than one large hole.

m

 

[dewiniaid]

Another trick to prevent internal noise from the slapping cable...
No help on the hole size but a trick I learned from my father for
eliminating that noise is to place any cables/wires in the mast inside a
length of closed cell foam pipe insulation (the kind you put around water
pipes to help prevent freezing)James Ward,
S/A Fortunes Lady (V1469)
Portsmouth/Norfolk, VA

 

[wxt8981]

why not just get a plastic coffee cup (or 2 or 3), punch a hole in the
middle- costs you
nothing but works wonders (at least on my boat)
Wilhelm V-257

Ward, James PO wrote:

 

[stevebirch2002]

Hi All

This is a way NOT to stop the noise of cables in a Vega. When I purchased Southern Comfort Iwas amazed that there was never any noise from the mast cables. After the first year of sailing her I decided to change the 25 year old cables during the lay-up period. With the mast off I thought it would be easy but it turned out that the first owner had poured a tin of glue down the top of the mast so that the cables stuck to the side of the mast. A good idea until you came to take out the old cable!! I finally had to leave the old cable in and just squeeze some extra ones down, a tricky job. Luckily I lost the mast two years after and had a brand new one with cable ducting - luxury
Steve Birch Vega "Southern Comfort" V1703