31s GPS cable routing process

MechGuy

Well-known member
Joined
Feb 19, 2024
Messages
59
Fluid Motion Model
C-302 C
Vessel Name
Sapphire
I bought a Vesper Cortex to replace my Garmin 300 AIS and I need to install the Vesper GPS antenna on the mast and run the cable to the area at the back of the dash. I'll probably install a new cable clam where the cable enters the boat. I'm wondering what the the best approach is as far as interior trim removal and cable path to do this? Thanks.
 
I installed the same unit in my R31 last year. The Cortex unit was mounted inside the cabinet behind the helm, starboard with all of the other helm electronics. I had considered mounting the GPS antenna on the mast, but it worked so well positioned in the cabinet across from the Cortex that I just bought a shorter coax cable and mounted inside. You may want to try this before routing all the way to the mast.

If you do choose to run to the roof, I have heard that the cable path is in the hollow pillar on the right side of the windshield. I did not do this, but there are a few posts here that talk about this same access for other cable runs to the mast.
 
Thanks Haifisch, that’s good to know. I’d like to go to the mast if possible for gps accuracy if it’s not a huge undertaking. I’d like to avoid taking apart interior pieces that are not needed to remove to accomplish the routing.

Where did you connect to power?
 
My boat has a command bridge but I suspect routing would be similar. I had read many threads that indicated the internal GPS antennae "worked fine", but the way my AP acted up I decided it must not be optimal. Some days it would be okay, other days it would not hold a course at all. "SPEED SOURCE FAULT". So I decided to spend some time and do the best I could.

I put the GPS antenna on the bracket (#8) where the XM/Weather antenna would go if I had one.
Down the mast, out at the bottom, and into the interior of the boat through the same gland as the rest of the antenna mast cabling. There isn’t a lot of room in the top entry port in the mast, if I decide to put more “stuff” up there I will likely lose the satellite TV dome (can’t see ever using it) and free up some space.

Inside, first remove the curtain rails and the teak boxes they are screwed into on both sides forward of the 2 teak pillars (the upright boxes between the windows with the shelves and lights). Then remove the 4 screws holding the vertical teak back on the "cubby" that runs across the boat . Tilt the top ahead and you can wiggle it out of there. Then you have access to the 3-4” between the fiberglass exterior and inner roof panel. Locate and fish out the end of the new cable and push it down the starboard pillar with a fish tape. Another route would be along the roofline to the front, then down the window pillar. I couldn't figure out how to take the window pillar off so I elected to go behind the refrigerator, which I had out a couple of times previously to work on the Webasto.

Remove the door and hardware from the refrigerator, remove the 4 screws on the front securing it, slide it straight ahead and out, then ahead and out of the way. No need to disconnect any wiring, lots of length for this. Crawl in, locate the end of your cable and route it ahead to behind the helm. There is extra room in the fuse panel there to tie in power.

It took a bit of time, but I'm happy I did it.
 
Thanks RWHenhouse, that sounds doable. The refrigerator removal sounds like the most time-consuming part of it.
 
RWHenhouse, I was able to get the gps cable routed like you suggested except I didn’t remove the refrigerator but used a fish tape to feed the cable forward once I got the cable down behind the starboard drawers, forward of the sink area. Not the most pleasant experience but Im glad it’s done. Thanks for your help.
 
RWHenhouse, I was able to get the gps cable routed like you suggested except I didn’t remove the refrigerator but used a fish tape to feed the cable forward once I got the cable down behind the starboard drawers, forward of the sink area. Not the most pleasant experience but Im glad it’s done. Thanks for your help.
Happy you got it! I'm getting good at pulling the refrigerator - have had to get in there 1/2 dozen times to fiddle with the Webasto heater, once to refill sonar transducer. You'll be in there sooner or later!
 
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