Adding radar - on pole or arch?

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Minerva

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I got a too good to refuse, new old stock, raydome to add to my 34ft centre cockpit boat in the Black Friday sales.

Now I’ll need to fit it. It’s going on the back of the boat, not the mast - I have mast steps and if it’s on the front of the mast I won’t be able to climb the steps on the front of the mast past it…

I was going to put a pole up with a couple
of struts - fairly straightforward and simple. However last night saw 316 40mm handrail tube for an attractive price and they also got 90° elbows so don’t need to worry about bending the tube.

316 Radiused 90 Degree Elbow To Suit 42.4mm x 2mm Tube

3 Metre 316 Grade Stainless Steel Tube 42.4mm x 2.0mm Wall Thickness

I recon that a couple of goal posts could made, and either welded (got a mig machine in garage) or drilled & tapped easily to make a stern gantry to mount the radar on - plus could move the solar from the guardrails too and when we remake the tent, extend it to the arch providing a covered place to hang wet foulies to dry aft of the cockpit.

Think that’s what’s called scope creep…

What else should I consider / what am I overlooking?

Thanks.
 
IMO a pole puts the scanner too low. Mine is on the arch, came out of a ria into a 3m swell and couldn't see the fishing boats on radar that I knew were there as I could see them when we were both on top of the swell.
 
Can you not introduce a platform, extra steps to allow you to climb past any attached radar.

The radar is so much more powerful as a navigation tool the higher the location - its line of sight + - which is much better - up the mast

A photo of your mast might engender some options for you.

Jonathan
 
We see lots of French boats with the radar mounted on a spreader on the mast. I have no idea how this impacts on performance with the mast to one side. I also recently saw a Gunboat with the same installation, so I am guessing it must work ok
 
Our pole has been entirely satisfactory. It has additional bracing to the pushpit. It may be that range would be increased by having it on the mast but in practice ships are seen at 12 miles or more, which has been quite enough for me, and with the bonus of absence of sea-clutter. The choice or pole or arch would depend on the boat, and perhaps on what else you want to put up there, such as a solar panel. I think the backstay option is perhaps more suited to larger boats with beefier rigging.

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geem said:
We see lots of French boats with the radar mounted on a spreader on the mast. I have no idea how this impacts on performance with the mast to one side. I also recently saw a Gunboat with the same installation, so I am guessing it must work ok
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That might work ok for bigger boats, but suspect that would look daft on a boat the size of mine.
 
johnalison said:
Our pole has been entirely satisfactory. It has additional bracing to the pushpit. It may be that range would be increased by having it on the mast but in practice ships are seen at 12 miles or more, which has been quite enough for me, and with the bonus of absence of sea-clutter. The choice or pole or arch would depend on the boat, and perhaps on what else you want to put up there, such as a solar panel. I think the backstay option is perhaps more suited to larger boats with beefier rigging.

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12miles range - that’s good to know. I can’t foresee wanting to “see” much further than that. what sort of height above sea level - your boat looks around 34/36ft so broadly similar to us.
 
Minerva said:
12miles range - that’s good to know. I can’t foresee wanting to “see” much further than that. what sort of height above sea level - your boat looks around 34/36ft so broadly similar to us.
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I've not measured it I'm afraid. The man who fitted it asked me how long I wanted it and I said I hadn't a clue, but well clear of the boom perhaps. The boat is a 34.
 
Minerva said:
12miles range - that’s good to know. I can’t foresee wanting to “see” much further than that. what sort of height above sea level - your boat looks around 34/36ft so broadly similar to us.
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What radar is it? Ours regularly sees pot markers a few hundred metres in front, so it’s not all about long range. That’s a newer set though which older ones may not manage.
 
WindyWindyWindy said:
A pole would make for easier maintenance when the bloody thing breaks... :(
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That’s a large part of our reasoning to mount on the backstay. Though we recently found that it’s a PITA when it is necessary to take the mast down. Our radome is gimballed, I can’t say that it positively does improve the radar image but I like to think it does.
 
12nm is good for shipping but radar offers so much more, land over the horizon from the deck and tracking weather, specifically thunder storms. The more notice you have of thunderstorms and rain the easier they are to track and take evasive action.

Our Simrad Broadband 10 years old, mast mounted (chosen for its low power usage and 'instant on') could plot the dinghy tied to one of the transoms.

Jonathan
 
Thanks all - I’ve ended up ordering this
Osculati Adjustable Width RIB A-frame - Force 4 Chandlery

when mounted on the push out it’ll put the arch at 1.9m and the radar atop its 150mm mini mast it came with will be comfortably above head height. I expect the arich will need some modifications to make fit widthwise and some bracing, but at <£400 delivered felt like a jolly good base to build
From indeed!
 
One problem with a stern arch is getting the radar below the solar. If it’s above then the shadow cancels the solar panel out as does any antenna fitted. If below then it may be low enough that it’s aimed at your (slightly warmer) head. So needs some thought.
 
Pole. Less weight and windage aloft. Easy access for maintainence. Are you really bothered by targets 15 miles away?

The pole could incorporate derrick for the outboard, other anennae, etc, or on my last boat the ensign.
 
lustyd said:
One problem with a stern arch is getting the radar below the solar. If it’s above then the shadow cancels the solar panel out as does any antenna fitted. If below then it may be low enough that it’s aimed at your (slightly warmer) head. So needs some thought.
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My initial thought is the solar panels fore and aft with the raydome in the centre. Should give decent coverage with minimal overlap / shadow. I’ll have a play around on CAD / with the arch when it arrives to work out best layout.
 
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