[C320-list] GPS Antenna Installation

[Jeffrey Hare]

Quentin,

As Chris pointed out, you need to drill metal on low speed and don't let it
get too hot.  Let the drill bit do the work and don't push too hard.
Occasionally spray the bit with oil.  

I think it took me about 20 minutes to get this hole drilled. I mounted mine
as you are attempting and drilled 3/32" pilot hole, then widened it to about
1/4" or 3/8"  (don't recall exactly, but it was enough for both speaker wire
and gps in my case)

Save yourself a lot of aggrevation and use a high quality bit for cutting
through hard steel.  Titanium doesn't necessarily mean good.  You'll find a
huge difference between low and high end bits.  I used DeWalt bits for this
job which are a medium quality bit.  Avoid the cheap Home Depot / Lowes bits
like Vermont American, etc. unless you like buying/breaking a lot of them.
They look good but are mostly junk in this application.

Important note:  If you centered your new drill hole between the two
stancion bolts from below, make sure you angle the hole AFT.  The bolts
holding the stancions don't go straight down so .  If you drill straight up
centered between them, you won't come up inside the stancion pipe!

Regarding the Speaker wire on starboard and port sides,  this was one of the
most miserable tasks I've done yet on the boat.  You'll find that the
horizontal tubes are welded into a solid vertical tube.  No hole exists for
feeding the speaker wire from the vertical tube over into the horizontal
tube.  I did manage to do it though.

After removing the plastic stern rail seats, I drilled the speaker wire exit
hole in the horizontal seat support tube at a point on the curve where I
could insert a long drill bit in the hole in to drill a hole the vertical
tube.

I could fill you in on more details if you want.

-Jeff Hare


-----Original Message-----
From: Quentin Murphy [mailto:qmurphy at sympatico.ca] 
Sent: Saturday, September 23, 2006 12:52 PM
To: C320-List
Subject: [C320-list] GPS Antenna Installation

I'm installing a chart plotter on the pedestal and will be mounting the GPS
antenna on the pushpit starboard side of the ladder.  From inside the
starboard aft locker I'm able to get a drill to the underside of one of the
pushpit's "stations".  When I drilled through the fibreglass from the
underside about two shot-glasses of water came out which I found strange.
Anyway, past that point the going got extremely difficult and completely
dulled five titanium drill bits in no short order.  I then tried with a tiny
bit which has unfortunately broken off up in the hole which I cannot get
out. I presume I will have to abandon that hole now and try another route. I
would think I'm encountering problems because the stainless steel tube is
welded to the flat mounting bracket and there could be a big glob of wend in
there at the base.  I was also planning on using this route as a feed for
the starboard observation seat speaker as my boat is not prewired like later
models.  Can anyone tell me how you managed to drill through this very tough
material?

Quentin Murphy
Celtic Knot #667