Radar Scanner Mounting

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AlistairC

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What are peoples feelings about the pros and cons of mounting a radar scanner on the mast or on a pole on the transom/pushpit.

I knew I shouldnt have gone to LIBS, Radar was a 2008 Planned Purchase /forums/images/graemlins/smile.gif
 
I have just bought a radar and am having mounting concerns too.

I have decided against the mast as 1) I have a gantry set-up already at the transom, 2) easier to get to on the gantry for installation & maintenance, 3) won't chaffe the sails, 4) The extra height won't make a great deal of difference in range (so I'm told) and keeps weight lower down!

My confusion is that most boats have the radome offset (either to port or starboard) - but the installation guide suggests it needs to be on the centre line?? What difference will this make??

Also if I mount it on the gantry at the back of the boat, will the wind generator also mounted on the gantry cause interferance?

Sorry to add questions to your post - but hopefully some of my 'transom mounting' rationale above my help?

Jonny
 
When planning my radar 3 years ago, I plumped for the mast because;

Radome is well out of the way from knocks and brain frying
Better range (marginal)

Main disadavantage of the mast is getting it mounted (mast down job) and servicing it. My gamble was that it would not need any attention. I was wrong on that one, but it was not too much of a pain to get down in the end.

Never had a problem with sails snagging it as some skippers say they have.

If I had a goal post already at the stern, I might have reconsidered.

Stern is no doubt easier to get at, also may well have a better radar view as the mast is not obstructing the microwaves. But the goal posts are more liable to damage from locks and other boats who don't look out.

Just look around your marina, I think the majortiy of boat radars are on the mast.

Pays yer money and takes yer choice really, and leave the credit card at home when going window shopping /forums/images/graemlins/smile.gif /forums/images/graemlins/frown.gif
 
Mine is on the transom (starboard)-side. Not my choice, it was already there.

It's convenient if you lower the mast every year (winter stowage), as you are having less cables to worry about.
I also mounted the Navtex antenna at the same post.
I fitted a small block so I can now operate my sign for running under engine power (the black plastic thingy) without leaving the cockpit.
The actual range of the radar (on paper 16 NM) seems adequate. Also, because it's not as high as it would have been mounted in the mast, it's easier to maintain (although I haven't had any problems yet).

It's more expensive though. More stainless steel involved.
I have not witnessed any problems with the set being off-center. And it can't be at the center-line because of the backstay.

Some people find it unpleasing to the eye to see it on the transom. I have no clear opinion on this. It does disturb the lines of the boat on one hand but it also looks very 'ocean going' as well :-) (Put a wind generator on the port side, and you are ready to sail away...)

You might consider using a tilting platform (very expensive) to enhance performance when heeled.

Cheers,

A.
 
You also need consider helicopter rescue when cluttering up your cockpit ... I believe the aft port side is their favoured landing spot ! /forums/images/graemlins/blush.gif
 
Puh!
Don't you carry your private helicopter below decks? I sure do /forums/images/graemlins/grin.gif
It's raised hydraulically and the mast folds away to provide some space. I thought all modern yacht had this as standard /forums/images/graemlins/tongue.gif
 
Radar mounted at the stern:
Pro's:
- easier installation and maintenance
- less disturbance to radar operation due to boat's rolling (exp. to the MARPA function, if you have it)
Con's:
- need for a sturdy post (or gantry): not cheap and esthetically conspiquous
- danger to the crew if the radome is not high enough above their heads (expecially for the helmsman, who may be standing most of the time)
- potential interference from other equipment mounted aft (windgen, aerials, etc.)

On my boat, despite having a gantry at the back, I moved the radome to the mast mainly on security grounds: I'm becoming geriatric fast enough without microwaving whatever is left of my brains! /forums/images/graemlins/wink.gif
 
Mine was on the mast just below the upper spreaders on last boat. I moved it to allow cutter rig. Fitted it to a second hand boom 14 ft long mounted on Sbd quarter with 2 SS tubes as supports. High-no fry, lots of room to hang spare VHF,Natex,GPS,TV aerials, windmill charger, derrick for outboard,etc. stern light, horn. All cabling long enough below deck to allow the whole shebang to be lowered, but it's strong enough to clamber up, (13 stone weakling). Radar beam does not seem to be affected by mast in front, probably due to beam width.
 
For all practical purposes, the blind spot is unnoticeable most of the time (remember that the antenna is wider than the mast, so some signal does go straight back!).

For that matter, I have noticed more frequently a blind spot straight ahead, typically at night with the wet genoa fully rolled.
 
Just shows how views vary. I can't even understand why why anyone would place one up a mast in the first place....

Its not only the difficulty in servicing the unit, but the weight aloft, plus the ugliness, and the disturbance to MARPA plots caused by the wider angle of roll.

That's why I'd plump for stern pole mounting anytime....
JOHN
 
I do not really disagree.... /forums/images/graemlins/wink.gif

...but my point is, in order to install the radome at the stern, it needs to be much above the heads of the people in the cockpit (the radar beam is some 15 degrees above and below horizontal, so people on deck will probably be exposed anyway, but they are farther away from the antenna compared to the helmsman!).

On my boat, this was difficult to achieve with gantry, bimini, windgen and all other bits of kit, but I would go for that solution if a strong - and tall! - pole could be used!
 
Don't understand the concern on sails and halyards getting in the way.

Maybe because my radome is about 4 foot above the spreaders so is a little higher than normal. Never had anything snag it at all. The genoa just sweeps past it when tacking, be difficult to how it would snag it.
 
I had a new Furuno 16 mile unit mounted at about 7 meters above deck. When sailing in lumpy seas I had a continuous problem of mast whip causing the little drive belt that runs the array to jump off the toothed sprockets. That results in the obvious error "no signal from array" or some other similar message. When refitting the belt it always felt suitably tensioned. I never bothered to discover whether this was a typical Furuno issue, just made a mental note not to buy Furuno next time.

Whenever this happened, getting up the mast to refit the belt was sometimes not possible because I was often sailing alone and even with mast steps it's not too safe going up the mast in bad seas whilst not belayed. Levitation, no matter how momentary, is not one of my stronger points especially when the boat is not actually under you.

Those periods were spent without radar which when single handing is not clever.

That's the singular reason that my next radar will be fitted at the stern on the aptly named "radar arch". No mast whip and when something trivial does go wrong it's imminently more reachable.
 
Just measured our gantry - 2 metres above the deck - seems plenty high enough to me for mounting a radar scanner on - it would be at least 1.2 metres above the helms head when stood at the wheel.

Incidentally, Raymarine told me that mounting off-centre will mean the image on the screen is offcentre (surely this won't matter on a 37ft yacht?). Also been told the wind generator will affect performance if within 1 meter - sounds reasonable. I had a couple of thoughts on this though:

1) You can get brackets to mount GPS etc above the radome - this being the case if I extend the wind generator pole to give around 25cm clearance between the blades and the top of the dome can I mount the dome directly below the wind genny (ie so the wind genny pole is very close to the back of the radome and therefore the unit sits directly above the dome)?

2) Ovni clearly don't seem to think that the wind genny will affect the radar on their LBS exhibit ...

DSC00100.jpg


thoughts ??

Jonny
 
I'm really no expert on radar and it's mounting locations or assimilation to other gear but logically these are my thoughts:

I have sailed on many boats where the wind genny and GPS antennea have been mounted alongside radar scanners on a radar arch. Indeed one of my family members has a catamaran with them mounted so and there is no problem with the operation of any of these bits of gear.

As far as mounting radar off-centre and whilst I'm not about about to contradict the opinion of the people who make the stuff, I know that whenever I have mounted a radar scanner, there is a procedure to follow which aligns the scanner with the centre line of the vessel and ensures that the image that appears on the screen to be in front of your vessel really is in front of your vessel. Now if your requirement is so accurate that you want to know whether it is two feet to the right or the left, then I guess you will have a problem. My requirement of a radar image is that when I rush up on deck to see where the ship is, I can generally find it where the radar image said it was.

I hope this helps.
 
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