Garmin GMR 18 HD through deck fitting

N

NFCN

Well-Known Member
Joined
4 Sep 2006
Messages
197
Location
France
Visit site
Wednesday's job in Gosport is to fit a Garmin GMR 18 HD radar up the mast and run both the power cable and network cable through the deck (I am fitting it to a Garmin GPSMap 750 Chartplotter).

The other cables I have running down (nav lights & VHF) go through glands which can be separated when unstepping the mast. Can anyone point me in the direction of how to do the same with the radar power and network cables, or is this impossible? They do not look easy to cut. If impossible to cut, I assume that on unstepping the mast you have to take off the cables at the mast and mouse them for when stepping again?

Many thanks

Nick
 
I have the same radar, and run the power and data cables down the outside of the mast, with cable clips every 6" or so - I've done this because there is no more room in the cable duct inside my mast!
All cables go through a big cable gland in the deck - this was originally supplied with a rubber bung, into which you were supposed to make a hole for each cable with a slit to allow the cable to be pushed into place, but I have superceded this with a 'custom' bung made from self-amalgamating tape - just wrap a few turns round each cable, then push all the taped bits together and it all sticks - then add more SA tape to get the right diameter, tapered so that it compresses even more when the top of the gland is screwed into place. For added waterproofing, I put a good splodge of polyurethane sealant over everything once it's all screwed down. The gland is large enough to allow the large plugs on the radar cables to pass through the deck - I have not cut the cables, so there is plenty of spare length inside the boat - this is because of previous problems with an earlier radar, caused by water getting into a junction box under the mast base.
 
NFCN said:
Wednesday's job in Gosport is to fit a Garmin GMR 18 HD radar up the mast and run both the power cable and network cable through the deck (I am fitting it to a Garmin GPSMap 750 Chartplotter).
. . .
Click to expand...

Hiya Nick, I agree with Greenalien, use a deck gland. I have exactly the same unit to fit to my foremast and they are very heavy and very difficult to carry aloft due to their shape! I am fitting a ScanStrut self-leveling mount:(

BTW, are you in Hornet? PM me as I should be at Haslar Creek this week. ;)
 
Garmin sell a specific deck gland for this. It costs around £30 and is really good. It is part number 010-10580-00, Garmin marine network cable coupler.

From the description and photos in the brochures it is not apparent that this is a deck gland, but it is. You will however need another 2-pin deck gland for the 12v supply cable but these are no problem sourcing.
 
Yes, that's the one.

The Garmin radar comes complete with an additional 'field installable' connector for the network cable. The only problem is that you require a specialised crimping tool for the task.

I instead chose to shorten my cable by cutting it approx 1 metre from the end, cutting out the excess and rejoining by soldering the 8 thin cores (4 twisted pairs and screen) back together. I then wrapped the whole lot up with self-amalgamating tape. This join was then pushed back up inside the mast to keep it out of the weather.

It all works no problem.
 
Bloater said:
Yes, that's the one.

The Garmin radar comes complete with an additional 'field installable' connector for the network cable. The only problem is that you require a specialised crimping tool for the task.

I instead chose to shorten my cable by cutting it approx 1 metre from the end, cutting out the excess and rejoining by soldering the 8 thin cores (4 twisted pairs and screen) back together. I then wrapped the whole lot up with self-amalgamating tape. This join was then pushed back up inside the mast to keep it out of the weather.

It all works no problem.
Click to expand...

Just done this myself with same radar and plotter as op. The gland supplied is **** and will eventually leak (shame on you Garmin). The radar should be supplied with a spare connection (like a house phone connection) and instructions to cut the wire and replace. (explained in very simple terms)

You do need a specific crimping tool which is about £40 (or it was in Gibraltar) but your best bet would be to find your local marine electronics person and ask to borrow the crimps. (i borrowed, but then the the guy trusted me) If not prep it all yourself and get him to just crimp it, should cost no more than a pint or maybe a tenner.

I used a normal stainless deckgland and wish i done it that way in the first place.

Very easy to do, just make sure you have the wires round the right way (reasonable eyesight required, very small wires.)

Also adviasble to cut the end thats being left in the boat as less weather gets in there (we all hope). But in my case i had to cut the outside part, my plotter is outside so no choice really. It should be fine if you cut an outside wire, providing you use the proper tools i.e crimps and not solder. advisable to dab a smidge of vaseline on the end though when all crimped up.
 
If you really need to remove the network plug, then you do need a special tool to attach the new one.
Fortunately, you don't have to bankrupt yourself to buy the necessary crimping tool - one of these http://cpc.farnell.com/duratool/d00125/modular-ratchet-crimp-tool/dp/TL10334 should do the job.

In any case, the new-style digital radar cabling is vastly superior to the old type analogue, multi-core radar cables, which were a major hassle.
 
Last edited:
I too have a Garmin GMR18 with a 4008 and GMI 10 instruments. I routed the cables down inside the mast. The power cable is no problem, any cable connector can be used to joint the cable below deck. The data cable is ethernet and this can also be jointed just below deck level. I was fortunate enough to have someone who was able to do this for me. It is worth doing this properly to enable easy mast removal.

As for sealing the cable at the deck, the plastic bungs supplied by Garmin are NOT for deck work, so dont even think about using them, and dont blame Garmin for supplying them. IMO I would question using anything other than a proper desk gland. We are talking expensive equipment here (GMR18) dont spoil the installation for the sake of a few quid spent on something which will keep the jointed cables and the inside of the boat dry.
 
I have just done this. I would recommend using the Garmin coupler and the Garmin RJ45 connectors. You can get connectors and couplers from outfits like Maplin but they are not designed for ojutdoor and certain not for marine use. The coupler screws to the deck with a rubber gasket. The joint looks pretty tight, but I would lob some Vaseline at the cable entry just in case.

The crimp tool need not break the bank, Maplin do one quite cheaply that will suffice for the odd crimp jpb. Or if you can, borrow one.

What I would recommend is a cable test unit ( again available on line or Maplin type shops) because the biggest hassle is matching the untwisted cables in the RJ45 connector. Beg a length of scrap multicore cable from your friendly electronics or computer guy, buy a pack of cheap RJ45 connectors (Maplin again) and practice making the connections before you do the proper job. The test unit allows you to fix connectors at each end of the cable and then plug them in to the test unit to see if you have done it properly. If all the test lamps light up, that's a result. You should try the test with the cable just pushed in to the connector so that if you have got it wrong you can re-arrange the wires.

There are some good videos on YouTube showing how to do it.
 
samwise said:
Or if you can, borrow one.
Click to expand...

+1

This is a perfectly standard tool for computer networking, not anything specific to Garmin or boats. Anyone you know with the slightest pretensions to computer techy-ness should have one, I have had ever since I was a student needing to share an Internet connection around a rented house. I suppose all the kids use wireless now, but in my day there was always someone with a half-empty 300-metre box of cable under their bed, a bag of plugs, and a crimp tool available for a few quid.

Pete
 
I cut the cables on my garmin radar.
I use inline plugs and sockets from radiospares at the mast base, and tuck all the jointed cable loops up into a winch-handle pocket mounted upside-down in the main luff channel. The lighting and power cables use 3-pin rubber automotive plugs while the radar and wind head use multi-pin din plugs all liberally lubed with silicon grease
The deck glands can then be permanently sealed with your gunge of choice.
 
If you dont unstep the mast often then solder the joint and use glue lined heatshrink. It will be totally reliable, if you need to instep the mast cut the joint and remake. With a couple of feet of extra cable you have a lifetime of new connections possible and I plan to outlive my radar.
Plugs and conecters often fail in this application.
 
Thanks all. Job done yesterday (the mast) and today (inside). With some specialist help ended up running both wires down through a deck gland. Cut the power lead as usual and made a connection and also cut the ethernet cable, simply joining the 4 wires required by twisting them together and forming a seal. I now have a working radar and when I next unstep the mast it will take no more than 5 mins to undo the connectors.

Hardest jobs were rivetting the mount (you need a good strong rivet gun) and running the wretched ethernet cable down the compass pedestal guard - that took a bit of persuading!
 
You must log in or register to reply here.

Share this page

Top