Radome installation at backstay?

peaman

Member III
I intend to install radar on my 32-3, and I'm leaning towards installing the radome on the backstay, with a self-leveling support from Scanstrut. I wonder if there are compelling reasons to instead install it on the mast, or on a separate pole at the stern? Of course, a mast-mounted radome can have a longer horizon, but I wonder if that longer view is worth the trade-off of losing closer targets which are below the radar vertical beam width?

I have a B&G HALO 20 radome with a rated range of 24 NM.

What pros and cons should I consider in deciding whether to have the radome on the backstay, on the main mast, or on a separate pole at the transom?
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
The mast install is more difficult and the wiring is kind of a PITA. The backstay concept works, altho the swivel does need some regular maintenance.
I much much prefer the separate pole mounted on the transom top. A friend has the pole mount on his E-32-3, and it was reasonably easy to install, and the radar worked great when I did an overnight passage down the coast with them.
I have a stern pole for our radar, too.
It's all choices and options... and choosing a potential advantage or drawback that you can live with.
Previous discussions:


 

Teranodon

Member III
... I wonder if that longer view is worth the trade-off of losing closer targets which are below the radar vertical beam width?

I don't think that this is a factor. My new Garmin Fantom has a (typical) vertical beam width of 25 degrees, so it wouldn't miss anything up on the mast. In general, range should not be a big issue. The main use of a radar is to warn the skipper about things that are potential hazards within 0-3 miles. In the old days, it was good to be able to spot distant islands, headlands, etc. But, today, the chartplotter takes care of that.

The large beamwidth also makes paying for a stabilizer problematic. And then figure that you may be motoring if you really need the radar.

I put the Garmin on an 8' Seaview pole. It was more complicated than I expected because I needed to stabilize the pulpit a bit. I chose not to go the backstay route because it gave me the willies. But I have not actually heard of a rig failure caused by a radar.
 

toddster

Curator of Broken Parts
Blogs Author
Dunno... my old radar had a blind zone of about 130 feet IIRC around the boat, with a mast mount. At the time, I had hoped to use it to help "feel" my way up some narrow, unlit, unmarked, and often fogged-in channels to the marina. (I'm not sure how well it would really have worked for that, anyway.)
I've definitely considered moving it down to the "tower of power" if/when that gets installed. But then there's the whole problem of shading the solar panels. Backstay mount is out, for me, I think, due to SSB antenna.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
My 2012 "Hi Def" radar shows all of the boats in our marina, as close as about 50 feet away. Lowrance 3G.
It's a big jump in resolution from our older conventional Furuno radar.
Picture link showing our post when it was aluminum, same height as the replacement composite pole, however.
 
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toddster

Curator of Broken Parts
Blogs Author
Yeah, I've since got a newer Raymarine "quantum" radar that is much better at showing small targets, but it's still up high on the mast, so in the marina, the picture starts about 1 1/2 or two rows away. There might be some reflections from nearby masts, so you can sorta make out the fairway. But yeah, it shows kids sailing dinghies, kayaks, jet skis, etc. that were just noise on the old set. And it resolves targets that are close together that the old set used to show as just a single blob.
 

peaman

Member III
Humm... price! The backstay scantrust costs the same as the most expensive radar in the market.
If you could find a cheaper radar antenna, would you be compelled to downgrade your mount? If you could get a perfectly working radome for $15 would you feel you should mount it on a pressure treated 2x4 lashed to the stern rail so as not to spend more for the mount than the radome itself?
 

peaman

Member III
my old radar had a blind zone of about 130 feet IIRC around the boat, with a mast mount.
130 foot would suggest a mounted height of 29 feet assuming a level installation and 25 degree vertical beam. Mast rake could greatly increase the blind zone at any height.

While I agree that motoring through fog is likely to happen with an even keel, the idea of losing all windward sea-level targets when sailing with more than 12.5 degrees of heel seems like more compromise that I want in navigation gear. A new self-leveling mount does require a big chunk of change, but it seems like the best means of getting the most out of the radar itself.
 

mbp

Ericson 34
I walked the docks today looking at sailboat radar installations. I talked to one owner who had a stern pole. He taught sailing for a local charter outfit for ten years, and had sailed on quite a few boats. He has, and much prefers, a stern pole for a radar dome.

He has seen a few jibs ripped or shredded by a mast mounted radar dome. He’s even seen a couple mast mounted radar domes knocked off their mount by a back-winded jib.

He has a stern pole that he built where the radar dome is “manually gimbaled”. His radar platform is pivoted at the top with two control lines that lead downward to cleats on the pole. He suggested looking at Garhauer Marine, which also has a manually gimbaled stern pole.

This strikes me as a reasonable solution. I would be using radar only in foggy conditions, and very likely motoring. When motoring, a gimbaled radar dome is not necessary. But a manually gimbaled radar platform allows for the possibility of adjusting the radar dome if sailing in conditions where radar is desired.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Something to remember here is the danger in over thinking.
No matter where on the boat you mount the radome (well, within some limits...) you will be SO pleased by the new "view" that it provides. :)

i.e. as useful as this discussion is, just having a working radar solves 90% of the prior 'blind' difficulty in knowing what's out there and steering accordingly.. I think that all us owners do ponder the choices, but it's good to keep your eyes on the prize, as it were.
 
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