Mounting Radar pole on stern deck of CD31

[Mike Davis]

I purchased a Garmin 18 inch dome radar system and have a stainless steel pole that I want to mount it on. The pole is measures 110 inches high, I want to mount it on the stern deck and put stainless steel struts and collar from the pole to the deck and then use backing plates for more stability. I also think I will fasten the pole to the stern pulpit. Does anyone have experience doing this project, what was your setup, and do you have some advice. The pole is heavy. Thanks. Mike

[mgphl52]

Hi Mike,

This is a radar arch that a previous owner mounted on KAYLA. While he never installed radar, he did put a 75watt solar panel on the unit and an external GPS receiver. The panel is over 15 years old but still works great!

[Jim Walsh]

I purchased a Garmin 18 inch dome radar system and have a stainless steel pole that I want to mount it on. The pole is measures 110 inches high, I want to mount it on the stern deck and put stainless steel struts and collar from the pole to the deck and then use backing plates for more stability. I also think I will fasten the pole to the stern pulpit. Does anyone have experience doing this project, what was your setup, and do you have some advice. The pole is heavy. Thanks. Mike

I don't have a pole, my radome is mast mounted, but a buddy of mine mounted his radome on a Scanstrut pole mount last year. The Scanstrut pole kit includes a universal base, a deck strut, and a rail stand-off. It seems you will have to have a plate welded to each end of your pole. One as a base mount and one as a radome mount. You will also need a backing plate for the base mount. A competent welder could also fabricate a deck strut once you determine precise placement. A rail stand-off, normally necessary for stiffness, may not be required if the pole you have has a thick enough wall. This should be an interesting project. If you don't have the welding skills then I'd advise you to get started before the spring rush when a competent marine welder is inundated.

[tjr818]

If you do not incorporate a rail standoff you might want to think of the pole as a giant lever trying to pry the deck off of your boat when you design the backing plate.

[jbenagh]

You need a large, strong backing plate. Off Halifax, on a CD36, in 10ft seas and 35kts, I was steering when a Scanstrut let go from the deck due to insufficient backing plate. As we tried to fix it, the forces on the end of the pole were pretty large. I think the long lever arm of a single support is a mistake. I'm not sure you can get enough support from the rail, depending on the type of weather you sail in.

Jeff

[Frenchy]

Yet another thought (I hope I'm not guilty of piling on) : The weight of the stainless pole when you're heeling 30 degrees
or so won't help the situation. I think most radar poles are aluminum to kind of reduce that. - Jean

[mgphl52]

I think most radar poles are aluminum to kind of reduce that. - Jean

Yes, the frame on KAYLA is aluminum. It's also a great hand/arm hold when heeled over and nature calls...

[jen1722terry]

I recall seeing a few sailboats over the years with the scanner mounted on the fixed backstay.

Google "radome on backstay" and you should see photos of a product also made by ScanStrut. Not sure of the cost or whether this is a good location, but you could probably find a few sailors with this setup on this forum or Cruisers Forum.

Seems like it would be less hassle and expense than building a custom pole mount, and possibly less obtrusive.


Just a thought.

Terry

[John Stone]

I don’t have radar, but if I did I think I would have it on a pole and not on the mast or backstay, though I know those options are very popular. I don’t think you have to have diagonals. But you will need a wide base (6”x6”?). You’ll need an even bigger backing plate (1/4” G10 would be a great choice).

You’ll also need to drill and install epoxy plugs in the deck to (a) isolate the balsa core from the boot holes and (b) so the compression loads exerted as you tighten the bolts and nuts of the deck/backing plate don’t deform or crush the deck.

Without struts, which clobber the deck, you will need some gussets welded between the bottom of the pole and the deck flange. I think SS is ok provided it’s not too heavy. Your are adding weight up high with radar anyway but on a 8’-9’ pole it’s not as high as if it were on the mast. Connecting it to the stern pulpit via a brace is certainly helpful but probably not essential if you have a strong wide base and gussets.

I like the set-up in the picture of Kala—the solar panel, gps antenna, and you could put your vhf/AIS antenna there as well. Very practical. Also could mount a small rotating arm on one of the vertical poles for dinghy outboard engine hoist. Also, if the main sheet traveler were mid boom you could use the arch to attach an awing to the back of the dodger while under sail. It comes down to aesthetics.

I prefer a simple, clean, uncluttered visual look but there is a kind of beauty to practical solutions as well. Just depends on your needs.

So many options available.

[fmueller]

Going thru the same thought process ... taking my dome off the mast ... have been considering a Scanstrut solution on the aft deck.

Scanstrut have poles of differing sizes and various bracing options, including a bracket that couples their poles to your existing pushpit tubing Jim mentions above. Combine that with a few pole to deck braces and a proper backing plate under the deck mount and I don't think I'd need to worry about strength. I don't think I'd trust my DIY skills with any ad hoc pole and just welding plates on either end ... but that is just me.

In my case it might make more sense to have the pushpit extended into a modest "arch" which might carry the dome and maybe eventually a solar panel(s) and be a tie off for a sunshade and/or a spot to mount the fishing pole ... and so on. These arches seem to be increasingly popular for a number of reasons.

Fred

[mgphl52]

If anyone is interested in more details of KAYLA's arch, please let me know and I will take additional pictures and measurements.

[David Morton]

Hey, Guys,
Just wondering what's the upside of mounting the radar dome somewhere other than the mast? My dome is mast mounted, out of way and out of mind, does not interfere with the rigging, and produces an excellent scan image. Adding another suitable pole at the transom seems to be adding structural complication and, IMHO, detracts from the aesthetic lines and silhouette of the boat.

David

[John Stone]

David
There is no right or wrong with the two methods discussed. You stated the real advantages of mast mount—longer range scan and you are happy with it on the mast.

Aesthetics though are a matter of personal taste. To me, radar has a less displeasing quality on a stern mounted pole than in the mast. But I also have a taller more slender mast than a stock Cape Dory. It’s just personal taste. Also, the weight of radar will have less influence on heeling on a 8’ pole than up 30’ high on the mast. There is less wire in the mast with a pole mounted radar and its easier to remove/repair on a pole than on the mast. If you fly a spinnaker your won’t foul it on the radar if it’s on a pole/arch on the stern.

But, range is greater on the mast...no doubt about it. And if range is the over riding factor, or if it’s more aesthetically pleasing to you on the mast then it makes sense to mount it there. I think lots of sailors have radar on the mast and are very satisfied with the results.

[Steve Laume]

I went with the mast mount for a number of reasons. Increased range was probably the least of them.

Raven is heavy in the stern and that seems to be valuable real estate for a bunch of other stuff. The mast mount was far cheaper and simpler to install. If you are ever going to add solar panels back there, then the radar dome is going to shade them at least part of the time. I have never had any issues with down wind sails. Ease of maintenance is was not an issue for me as I doubt I would be able to fix anything in the radar dome if it was sitting on a bench at home.

I also didn't want the pole to get in the of my fishing rod, when fighting a fish, Steve.

[jen1722terry]

Speaking of radomes, ours is about 12 years old. Still works great, but does anyone know how long these things last? We do use it more than most folks as we live aboard all summer is fog-land.

Terry