Radar installation

Maine Sail · Apr 5, 2009

Spar / Stern Pole

Roger Long said:
First of all, thanks to Mainesail for his analysis in my thread asking about Lorance. Why not get an essentially free chart plotter and set of charts by going Garmin? I was worried about display unit size but, if the Garmin display instead of my laptop can be the inside navigation system, I've saved a lot more than a couple inches in display unit size.

Much as I hate to buy just before digital units come out, I'm beginning to think radar is essential to my cruising plans this summer and starting to think about installation. Mast mount is out of the question this year. Too much major surgery for the cable runs to do in time. I'm not sure I want to drag my jib over it all the time either.

I see plenty of boats with the radar mounted on a stern pole. The Garmin manual says to keep everything out of the beam. How serious an issues is this?

There is no convienient place for a pole mount on my boat with all the real estate taken up by the wind vane and narrow side decks. The weight of the vane gear also makes keeping addional weight to a minumum a priority. I'm thinking about using Bimini tubing and hardware tubing to make a light arch mounted on the stern pushpit railing. I haven't had my hands on a Bimini in years but it seems that, if they can hold the canvas tops in place in a sailing breeze, they should hold an 18" radome. Any Bimini owners have an opinion?
I would probably need some additional stiffening struts that are not shown on the drawing above. Whatever it is, it's got to be quick and easy to construct if I'm going to do it this year.

Roger,

A mast mount is less expensive and it takes about 2-3 hours to install with the mast down. A good snake, some drills and taps or some monel or aluminum rivets and a grommet is all it really takes. Garmin uses a Cat 5 connector with a separate power wire and it is easy to cut and or splice, much easier than an all in one cable.

Pole mounts just don't perform as well due to height. I say this and currently own a stern pole so I am not being biased just because I currently own a mast mount because I don't currently own a mast mount.

As for dragging your jib across it I have never had one tangle of my head sail on my dome and I have owned three boats with mast mounted radar and sailed on many. If you let your crew drag the head sail across on a tack using the sheets then you will likely have issues but if you let the wind tack your sail then you should have no issues..

Garhauer has about the best deal on a stern pole and they are stainless steel. If you go custom with an aluminum pole be sure to have it Awlgriped with their special primers for aluminum (usually zinc chromate based) as un-annodized aluminum does not like salt air..

Going bimini tube would likely require at least 1" thick walled tubing 1 1/4" would be better. This tubing is quite expensive as are the connectors. I think you'd find a Sea View SM18U (LINK) spar mount, for about $200.00, to be a less expensive solution.

Tim R. · Apr 5, 2009

What about backstay mounted? I fabricated a backstay mount for my Pearson years ago and it is now on my Ericson. It is constructed of thick wall 1" SS tubing and rail fittings I bought at Hamiltons and some Delrin I bought at Maine Plastic Supply. It took me half a day to fabricate.

Here is the bracket custom made from Delrin that allows the backstay to slide but keeps the pole up.

The bottom bracket allows the pole to pivot down for service. It is a boarding ladder bracket I found at WM. It was sitting on a shelf and they had no idea what it was so it was free.

You can see the 2 custom Delrin brackets used to secure the base to the tubing. The SS wire you see is the boom support(topping lift). All electronics wiring is run in the tubing.

The Furuno has since died so I now have this rig on my Ericson with my Garmin radome.

I am working on the boat all day Roger if you want to swing by and take a look. I also have some delrin left that you could use.

jsalley · Apr 5, 2009

I just installed a Garmin GMR18HD dome on a mast mount with the stick up (wife pulled me up in a bosuns chair X 4) and ran the cables through the bilge. I secured the cable to the underside of the cabin sole, so they are well above the bilge bottom (which is usually dry anyway). Altogether a one day job.

Roger Long said:
Ah, that I probably could snake down through my mast support tube. I was thinking of the big fat cable I saw on the other radars. Another plus for Garmin.

However, I would have the wires running inside a pipe mast support loosely bundled with VHF and lighting wires. Running through the bilge would then be the only route without an extensive interior liner disassembly. Garmin says not to do either. Often these kind of recommendations don't transfer into real world problems most of the time. What do you think.

Ron20324 · Apr 5, 2009

That's pretty spiffy, Tim. I suppose that's the backstay anchored with that "custom" chainplate fitting? Interesting. Do you just have the one delrin support? I also trust the stern light is not seriously affected by the ladder bracket? An anchor chain-stopper would also suit as the lower pivot.

Tim R. · Apr 5, 2009

Funny you should mention the stern light Ron. My next project was to move the stern light to the rail because I did not like the backstay chainplate blocking it and then the radar pole mount made it even worse.

The tang you see there is custom for the mainsheet.

Don12364 · Apr 5, 2009

I made Mine

A length of 1" dia SS tubing, a square of 1/8" alum plate, 2 saddle clamps + through bolts to attach plate to top of arch and 4 jubilee clips to hold the arch on to the stern gate uprights.
Scanner height is just above boom and mast shadow dead ahead is nothing compared to mast shadow dead astern for mast mounted scanners.
Height is okay for collision avoidance as I get more than 10 miles range for ships and 5 miles for everything else.
Mount is not rigid but does not oscillate or vibrate with boat's movement so it absorbs shocks quite well.

John · Apr 6, 2009

backstay mount

Roger Long said:
Cool. I was sure I'd seen something like that somewhere. Now I know, it was on your Erickson I passed frequently.

I have thought of backstay mounting but the split backstay and adjuster keeps hanging me up. Your pictures give me some ideas.

I have a backstay mount on a split backstay. The mount swivels. It costed me $500. The one I have is from "Radar on the Level". Their web site is: http://www.radaronthelevel.com/

Radar installation

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