Radar scanner, mast or pole?

[tjc]

Having took the plunge and bought a new radar I can't make up my mind where to put the scanner. A look around the boatyard seems to indicate that most scanners are mast mounted. On my boat, 30 footer, it would catch (just) the genoa.

Some have mounted scanners on a pole on the transom which seems a good idea.

Any advantages / disadvantages with either method?

All tips gratefully received.

 

[Deleted member 478]

There are few schools of thought on this one:

The higher up the mast, the further over the horizon it will see (depends on how powerful your radar is) - debatable as to whether this is a good thing or not - i.e. reduced focus (more clutter), radar sees the ship and you cannot so you might discount the accuracy of the radar and go back to sleep.

The higher up the mast, the more it will effect your GZ curve (stability) - not good.

On a pole it will still give reasonable range (12 - 15 miles) and more focused but exposure to intense radar transmission in not healthly (cooks the brain) so you'll want the radar as high as possible.

If it's on the mast, there is a blind spot behind the boat because of the mast. The width of the blind spot depends on the width of your mast and the size of your scanner - surprisingly wide. How often are we told to look astern every 10 minutes when on watch and how often do you actually do so?

http://www.stingo.co.uk

 

[colin_jones]

Don't worry about a blind spot stern.

Unless you have a megawatt military spec radar with a one degree beam width, the effect of the mast will be adequately compensated by the wider ( gen 4 degree +) of a normal yacht radar.

My JRC is on the mizzen and I have never been aware of a blind spot.

In case therre is some confusion, the radar's power does not let it look over the horizon. It will give a stronger return at distance, but will not 'see further'. This is entirely a function of height.

 

[maxi]

Go for the pole. The scanner is more stable (less pitch & roll), the boat is more stable (less weight aloft) & maintenance is much easier.
As for range, if you can see for 10miles that is two hours of sailing & long enough to enable you to take action - why look for more?
5 years in and my pole on a 31 footer is problem free.

 

[PaulJ]

I would agree with all of that plus..... the Challenge Business put their scanners on poles and if it's good enough for them, I guess it's good enough for me.

 

[halcyon]

Most useful thread, when we bought the Halcyon she came with a pole and two braces that fitted on the stern, carried the radar and windgen.
First planned to scrap it, then put it in storage, now plan to reinstall it.

Brian

 

[pvb]

But, hey, aren\'t poles expensive!?

Thinking about fitting radar, and fancy a pole-mounted scanner (also useful for tidying up GPS/Navtex aerials, etc). But check out the prices! If you go for a standard Scanstrut solution, it's an arm and a leg. If you go for a custom-made S/S solution, it's all 4 limbs! Any ideas for keeping cost down and still having a good-looking, durable solution?

 

[Spacewaist]

The poles have it - what type then?

Stainless steel, say 35mm dia braced with two supports or a big fat anodised alumimum one?

If you have an after locker. a large dia (100+mm), anodised aluminium pole, bolted to the bottom of the after locker and braced as it goes through the deck takes up much less deck area at the expense of some locker space.

I have one so mounted on the port quarter of an admittedly 42ft boat and I have never regretted it. Each time I look at one of those stainless steel contraptions just renforces my conviction!

LOOK OUT!!! Behind y.......! Five more hoots and you're history!

 

[wpsalm]

Re: Radar scanner, seeing over the horizon

Mast or pole I use a pole mount and have found signal return through the mainsail to be somewhat weak easy enough to deal with a change of coarse for a few minutes but then my radar very old and power hungry so I tend to use it for brief looks anyway ..also eventually you,ll need to take it down for repairs yes hopefully thats years away..but you be glad it,s on a pole when that day comes...as for seeing over the horizon the owners manual for my Furuno explains it this way ....visible horizon plus 6% radio waves bend slightly even the very high freqs.

 

[LadyInBed]

Re: Alternative to a pole . . .

I whuld consider an 'A' frame across the stern. There would be room on it for solar panels plus Naxtext, GPS and TV arials. Then along the forward edge a fold away Bimini.

 

[rhinorhino]

How about on the back stay?
See picture of HR43 on HR's website. I have sailed that boat and the set-up works well.

 

[Jacket]

Is that safe? I'd have thought that in rough conditions the weight of the radar would apply large flexing shock loads to the backstay, leading to eventual fatigue failure of the stay?

Hope I'm wrong though, because as you say, it looks a good place for a radar.

 

[claymore]

Me too - plus if anything goes wrong with it - its more accessible on its pole.

regards
Claymore

 

[jtwebb]

I have a self tacking jib on a Dehler 36 which would have caught the radar. Hence, the scanner is fitted on the side of the mast. The head is set up to rotate the picture electronically. It is on the starboard side to 'look' the way I have to look under Colregs! It does see to port fairly well, after all the boat is never absolutely steady in yaw. The autopilot compass feeds it heading 10 times a second which gives good, stablised EBLs and North up picture. I am not keen on radars at or near head height such as on a pole.

J Webb

 

[charles_reed]

There are advantages to both methods (assuming a sailboat).

Post -
reduced weight aloft, ability to gimbal the scanner, better short-range pix, less movement and therefore more accurate target positioning.

Mast -
greater range, less fixing problems.

You'll find the majority of long-distance sailors (and ALL the round-the-world racers) mount on a transom pole.

I've always found my radar more useful on short ranges (0.125 - 3M) than on long range (13-24M).

If you do sail seriously do gimbal the scanner - it improves the heeled picture dramatically.
I'd discount the sail interference cited - both positions can lead to problems - on mast with foresail, on the pole with leech reefing lines in a blow when you're reefing (unless you're one of those unfortunates with in-mast furling)

 

[Eudorajab]

2 years ago I had a custom pole made for Radar and Windgen for my 35.5. Installed it myself and while intitially costly, has served me etremely well. The main reasons I chose the pole options are as follows:-

1: Easier maintenance
2: No holes in mast therefore less chance of damage to mast (some insurance companies will not pay out for broken mast if you make mods to it)
3: Much easier to install.
4: Tidies up all cables GPS etc and allows space for duplicates i.e spare VHF antennae etc.

One thing you need to bear in mind though..... make sure the struts holdinf the pole are SOLID. Dont be fooled into thinking you can get away with cable as it just does not work.

Best of luck and pm me if you want more inot