# Radar - Stern Mount or Mast Mount



## night0wl (Mar 20, 2006)

So as I'm fitting out our new boat, the most hotly debated question so far has been where to mount the radar. Wasn't expecting that one, as I've always thought it was six in one, half a dozen in the other. But I'm told its very different in terms of range and clarity. So Sailnet, help me decide. Below, I've mentioned pros/cons of each approach. What does your boat have that works best for your and why.

Radar I have: Raymarine RD218 2kw Radome

*
Mast Mount*

PRO: Better range
PRO: Less cluttered cockpit
CON: Need more cable extension - provided 15 meter wont be enough, so minimum of 5 meter additionally needed
CON: Will need to buy a mast mount and climb up on bosun chair to install
CON: Will often catch on 140% Genoa when tacking

*Stern Mount*

PRO: Will be able to mount wind generator on stern pole above radome
PRO: No interference on tacks at all
PRO: Less cable needed to wire it, provided 15 meter should be plenty
CON: Less range than mast mount
CON: Cluttered stern, will throw balance with that much weight 10' high up
CON: Will need to buy stern pole mount or have one fabricated by stainless steel guy


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## mightyhorton (Dec 3, 2006)

I like mine up on the mast. It is out of the way. Buying more cable and having to climb the mast are not really valid reasons to be against placing it up there, it is a one time job. You have to buy some sort of mount either way. I don't use a 140% so don't know about that. The more stuff you have on the back of the boat the less clean air you have for your wind vane steering and the less real estate you have for other stuff that you can't mount up your mast. Shades your solar panels when stern mounted.


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## night0wl (Mar 20, 2006)

mightyhorton said:


> Buying more cable and having to climb the mast are not really valid reasons to be against placing it up there, it is a one time job. You have to buy some sort of mount either way.


I'd have to buy a stern pole anyway for my wind generator (looking at a KISS right now, wife is from Trinidad and will bring it back for me). But I generally disagree with that statement above.

The Radome cost me less than $900 new from West Marine on sale. With a mast mount, you're talking about a mounting bracket/contraption ($300) and an extra length of cable from Raymarine ($200 again). Then going up the mast is a rare treat - fraught with risk of its own. It may be one time costs, but then an extra 50% in parts is a tough pill...not to mention the difficulty in diagnosing something when it goes wrong. The stern pole would be much easier to issue diagnose/repair too.


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## Faster (Sep 13, 2005)

Both approaches obviously work... I'd argue that the extra range from a mast mount is not a significant advantage at the speeds and the conditions that we use our radar - I've never had it on max range anyhow.

Ours is on a stern post, it's integrated into the stern railing so certainly doesn't clutter the cockpit - but my primary reason was to be able to mount the display unit at the helm, where it makes more sense to me, than below.

With a small unit like ours the post will likely weigh more than the radome, but we've had no issues with our 2" SS post fabricated by a welder/machinist friend.

We have friends with a Passport 40 currently cruising in Mexico, and a larger radome on a gimballed mast mount. For reasons not exactly clear last month the welds on the support tubes failed and the radar was barely hanging on and significantly askew. Whether this was due to the drag of the tacking headsail, or simply the motion and mileage of long distance cruising we're not sure.


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## Omatako (Sep 14, 2003)

We have a post mount on the stern. Have never really had any issues with space, clutter, range or any of the others "cons" mentioned. I did have to extend the original cable when I relocated the display but that doesn't influence the choice.

I had a mast mount on my previous boat and had three different occasions while on a trans-ocean voyage where the drive belt on the scanner array jumped off (almost new unit). Never did discover why but once went up the mast at sea to fix and twice decided I could live without the radar until the next anchorage. It's also why I'll never have another Furuno.

As said, I have no issues with the pole mount at all and would probably do the same again next time round.


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## night0wl (Mar 20, 2006)

Does anyone with a stern pole mount have a wind generator attached to it as well? Care to share the pictures of the installation??!

After a standard gasoline generator (Honda EU2000), I'm planning on fitting out with a Kiss wind generator on the pole as well, followed by two 80 Watt Kyoceras on top of the bimini.


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## rikhall (Feb 7, 2008)

*Stern mount was our choice*



Faster said:


> Both approaches obviously work... I'd argue that the extra range from a mast mount is not a significant advantage at the speeds and the conditions that we use our radar - I've never had it on max range anyhow.


Hey - I do not know who _*Faster *_is, but I sure agree with him.

This is our second boat with radar, this is our second stern mount set up.

Things we considered:


we store our boat with the mast down - so, with stern mount, nothing to disconnect and no extra hole in the deck near the mast to possibly leak
we too, never use the radar on max range - except maybe to say - "_see that blob 16 miles away - that's Grand Manan Island!_"
we most often use it at 1.5 miles to 3 miles, Ya gotta watch out for all those lobster boats!
Did not clutter our stern at all - actually - makes a nice back rest to lean against when standing at the stern as well as something to grab onto climbing up the stern ladder
Gave me a place to hang extra antennas (Here is a of the mount on the last boat) 
















Being of frugal mind and empty pockets - the stern mount unit cost me less than 60 bucks total - Look at my link here 
All that said, some of my best friends have mast mounts 

Rik


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## night0wl (Mar 20, 2006)

Can anyone speak to the range aspect a bit more? How much more range (both on normal and full power) can you get out of the 2kw radome when it is mounted on the mast?


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## lbdavis (Apr 23, 2007)

0wl,

Not to complicate things too much, but there is a third, less popular, option and that is to mount it on your backstay. AN EXAMPLE


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## night0wl (Mar 20, 2006)

lbdavis said:


> 0wl,
> 
> Not to complicate things too much, but there is a third, less popular, option and that is to mount it on your backstay. AN EXAMPLE


I thought about this, but two things on my boat. Beyond the price (the scanstrut is $1400!!!), I the following worry me:

1) I have a split backstay, which may not have the wire diameter (therefore strength) to hold up the mount back there.

2) Like my feedback on mast mount, I'd like a multi-function installation that can support the radar for one, but also the wind gen. Unless someone is aware of backstay mounting brackets for wind-gens too!!!


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## Cruisingdad (Jul 21, 2006)

night0wl said:


> Can anyone speak to the range aspect a bit more? How much more range (both on normal and full power) can you get out of the 2kw radome when it is mounted on the mast?


Radar is line of site which means that higher is better (for line of site). There is a big dissagreement on whether a heeled boat has a significant effect on return, so I will not go there. However, in general, a mid mount is typical and what I have seen on the majority of sailboats.

THe stronger models actually give a better picture. Do they have more range? I guess. But all you will see is weather moving in since you once again are limited by LOS. However, I have not found it that much better and probably not noticeable for the typical user. Many dissagree and that is fine. Maybe if I lived in Maine I would opt for the 4kw too... maybe. For me and my application, I cannot see the expense.

I would not mount it on the stern. I strongly prefer mast mount. Also of interst is that I have never, not even once, had a jib hang on the radar. My biggest issue with mast mount is having to go the chair to fix something (which I have only had to do on Dad's boat). My biggest issue with the rail mount is actually having 2000-4000watts beaming around my mellon. Is that a real or imaginary danger? I don't know. Just bothers me.

In conclusion, put me squarely in the mast mount category.

- CD


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## genieskip (Jan 1, 2008)

On my previous boat I installed a new radar. The problem that came up and prevented my using a mast mount was that I'd have had to pull the mast to install the wiring inside the mast. I didn't want the wiring to be attached to the outside of the mast and so it would have been necessary to pull the mast to fit everything in. That proved to be the dealbreaker and I went with a homemade laminated wood tilting backstay mount.


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## sailingdog (Mar 19, 2006)

Cruisingdad said:


> I would not mount it on the stern. I strongly prefer mast mount. Also of interst is that I have never, not even once, had a jib hang on the radar. My biggest issue with mast mount is having to go the chair to fix something (which I have only had to do on Dad's boat). * My biggest issue with the rail mount is actually having 2000-4000watts beaming around my mellon. Is that a real or imaginary danger? I don't know. Just bothers me.*
> 
> In conclusion, put me squarely in the mast mount category.
> 
> - CD


Actually, it's been proven that CD's skull is thick enough that this is not a problem.  But for the rest of us, it might be...


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## night0wl (Mar 20, 2006)

I'm going to add a CON on the stern mount of "radiation damage while traversing on the coachroof area. Since the coachroof is 2-4 feet higher than the cockpit and walking around puts you at the same LOS as the radome, it is conceivable to me that damage is possible while underway.


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## PalmettoSailor (Mar 7, 2006)

night0wl said:


> I'm going to add a CON on the stern mount of "radiation damage while traversing on the coachroof area. Since the coachroof is 2-4 feet higher than the cockpit and walking around puts you at the same LOS as the radome, it is conceivable to me that damage is possible while underway.


This topic was recently discussed on the C36 Association e-mail list and this issue was raised. However, most folks don't use their radar all the time, so the exposure would likely be minimal and could be avoided all together by turning off the radar or putting it on standby while crew were forward.

As other have pointed out, mounting the dome higher on the mast gives greater range but the beam width is limited so you loose coverage close to the boat which could be important entering a rip-rap lined channel in the fog. Also, masts require maintenence and sometimes get pulled. Pole mounting removes one complication from that excercise.

I thought the decision would be a slam dunk for mast mounting but the arguments were persuasive enough for me to think I'll go with a stern pole when I get around to adding radar.


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## imagine2frolic (Aug 7, 2008)

Advantages to the stern mast are. As mentioned a good backrest, and something to hang onto if thrown. A place to set antennas, and a boom for lowering the dink's motor. If the mast should ever come down in a storm the radar could come in handy approaching land in this same storm.....i2f

Plus your antennas would still be in place also, vhf, gps, etc. etc.


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## Valiente (Jun 16, 2006)

I have yet to make up my mind. I have two very strong braced steel "tabs" off the end of the boat designed to take davits. I do not have davits. I do have a small deck crane and the other pad will take a wind gen pole. Throw in a windvane and it's pretty crowded back there. 

My mast also pivots down and I have a pilothouse. This argues for a mast mounted radome, as the cable run is very short. However, given that I am putting in a sturdy arch to support four solar panels, I could conceivably have a radome mounted there, but I think this is too low.

I will likely choose 22 feet up or so for best range. I will certainly wait for the new radar types to come out due to the better "near definition" and improved power draws.


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## sck5 (Aug 20, 2007)

Mine is on one of my split backstays. Nothing is cluttered and there is no problem accessing it or the wiring if needed. Not the cheapest solution but it sure is out of the way.


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## night0wl (Mar 20, 2006)

sck5 said:


> Mine is on one of my split backstays. Nothing is cluttered and there is no problem accessing it or the wiring if needed. Not the cheapest solution but it sure is out of the way.


$1400 for those self leveling backstay mounts...ouch! Thats labor + materials for mast mount...with room to spare. And much more to spare for a stern mount pole. Yowza


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## mightyhorton (Dec 3, 2006)

I suppose the definition of clutter is relative and personal, and is affected by how you use your boat. Cruisers tend to have a lot of stuff hung off the back of their boats - antennas, MOB poles, 'horseshoes', BBQs, extra anchors, outboard motors, SCUBA bottles, wind generators, fishing gear, ladders, wind steering stuff solar panels. The radome is one of the things that works well up the mast and off the stern, so why not get it out of the way? The radiation hazard is a good point - are you always going to remember to turn it off before going up on deck and/or are your crew and possibly inebriated guests always going to mention to you that they are going to run up forward? You are responsible for their safety, and it would, to me, be sort of a nuisance to have to worry about melting somebody's fillings.

Climbing the mast, _safely and with proper gear_, should not be a big deal to a sailor. Not to say there isn't some stress or risk in it, but it is important to go up there with some regularity to check things out, and to be comfortable doing so. The odds of the radome breaking are slim. Most of these things are using tried and true and debugged technology. It would be a bummer to have it fail offshore and to have to climb the mast in snotty conditions, but it might not be so much fun trying to get it off of the stern pole, either, if conditions were bad and you are working around wind generators, solar panels, archs, antennas, davits, dingys flopping around, biminis, etc. Bad luck, Omatako. My Furuno back lighting display failed on my 3 y/o old out of warranty unit, I carried it home from Mexico, shipped it to them, they fixed it for free and shipped it back to me for free. I love 'em!

Your use of the boat will dictate whether having the radome up high to see squalls or freighters or cruise ships approaching from far away is more important than seeing something in a rip-rap channel. For my cruising type of sailing, I'd rather see land or freighters or squalls further away, especially if I am flipping it in and out of standby with some miles in between looks. Freighters and navy gun boats and cruise ships moving at 30+ knots come up on you pretty fast, and if you see fishing boats and you suspect they have nets out you can make a better easier angle to miss the nets from further away. Mine is up the mast and my display is in my cockpit, under the dodger, starboard of the companionway hatch. Works fine for viewing from behind the wheel. I've never noticed whether my headsail comes close to the radome, but never had any issues.

And, frankly, my own personal bias is that it just looks better, more seamanshiplike, up there on the mast.

Faster, which P40 do you know in Mexico?


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## Vitesse473 (Mar 16, 2008)

I opted for a mast mount (RayM 4kw installed in '08). Personally, I don't like the stern mounts for several reasons (most personal). Having it up on the mast is a set it and forget proposition. Radar technology is not that great as it is, especially so on sailboats. I wanted height to help maximise target acquisition, and I don't regret the decision at all. I certainly, and most importantly, wanted to avoid contact with the radar beam. Case in point, our baby monitor goes schizo when the (home) microwave is on, and it's 10 feet away, and not 4kw. Yikes! The suggestion of simply putting it in standby mode is not an option. Turning them on/off is bad for the microwave device, and will shorten its lifespan. And, crew is not likely to do that anyway.

As for climbing the mast. Well, can't comment as I had my mast taken down for the installation. I would say that I think mounting it from a bosuns chair would be very difficult. 

Lastly, the genoa does not get stuck unless poor technique is applied. Most people when tacking will blow the jib as they start the tack, which is terrible technique (and bad for the sail). If you wait until almost in irons to blow the jib sheet, 1) the jib will still be driving the boat forward and 2) less sheeting in on the other board, which means the jib will flog a lot less (if at all).


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## jbondy (Mar 28, 2001)

I hope this isn't considered a hijack, but what is the potential for "damage" from the radome's radiation? Is this real, or akin to the concerns about cellphones causing brain cancer? If real, then it should factor into placement (and since I went backstay mount, means I wasted $s, but it won't be the first time). If not, it's just a distraction.


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## Cruisingdad (Jul 21, 2006)

jbondy said:


> I hope this isn't considered a hijack, but what is the potential for "damage" from the radome's radiation? Is this real, or akin to the concerns about cellphones causing brain cancer? If real, then it should factor into placement (and since I went backstay mount, means I wasted $s, but it won't be the first time). If not, it's just a distraction.


I do not think it is a hijack as it directly relates to the placement of the dome.

I honestly do not believe anyone knows whether it is harmful or not. I think there are a lot of guesses, but that is it. I tell you that it does bother me - real or imaginary. I have always heard that it is good practice to turn your radar off before entering a marina and to never look at a dome/array while it is running. Now, is there scientific proof that it will hurt you?? I doubt anyone has done a study of it. The cost of doing such a study would be extraordinary and you can be certain that a manufacturer of Radars sure won't support it. So, you are stuck with making your decision based on folklore and old wives tales, I guess.

Just my opinions... unless someone definitively knows better.

Brian


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## jrd22 (Nov 14, 2000)

I have always had mast mounted radar on the sailboats I've owned and have never had a problem with the genoa getting hung up on them. I have a power boat that has a 4KW radome at about 10' above waterline and I really can't see a lot of difference between the sailboat 4KW which is app. 25' and the lower one. Coming into our marina is a very narrow channel and I get about the same detail on both boats on 1/4NM range (maybe a little better in the power boat, but it's also a brand new radar), and when on the higher ranges (I rarely use much above 8NM here) they both seem to pick up targets equally well. I'm sure that the mast mounted would be more effective in picking up a target at the maximum ranges. The mast mounted gets it out of the cockpit and gives you more room for a wind gen, solar, etc. As far as servicing and installation goes, I built my own ss mast mount and installed it from the chair, not a big deal on the last boat but keel stepped you would probably have to pull the stick to run the cable. Based on my experience I don't have a strong opinion either way based on performance, but if I was planning on putting a wind gen and solar panels and antennas on the stern I'd probably opt for the mast just to declutter. It seems to me that MaineSail had a thread about this and he strongly favored mast mount, and he probably uses radar as much, or more, than I do.


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## Vitesse473 (Mar 16, 2008)

Cruisingdad said:


> I honestly do not believe anyone knows whether it is harmful or not. I think there are a lot of guesses, but that is it.


When I see something like this in the front of the Raymarine users guide, I would err on the safe side and heed their advice. I imagine the engineers have seen some pretty freaky stuff while testing these products. Ultimately, radomes emit a signal at a 25 degree angle, so 12.5 degrees below horizontal centerline. If you have that from stern to bow plus factoring the height of a tall person, than all is well.

From Raymarine User Guide, Page 5:
Radio Frequency Radiation Hazard
The radar antenna emits electromagnetic radio frequency
(RF) energy which can be harmful particularly to your eyes.
DO NOT look at the antenna at close range.
It is important that the radar is turned off whenever
personnel are required to come close to the scanner
assembly or associated equipment. It is recommended that
the radar scanner is mounted out of range of personnel
(above head height).
Distances from the face of the radar at which RF radiation


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## jbondy (Mar 28, 2001)

Vitesse473 said:


> When I see something like this in the front of the Raymarine users guide, I would err on the safe side and heed their advice.


I had not noticed that in the manual. I agree with you re erring on the side of caution. Although I can't help but wonder if it doesn't fall into the category of the warning on the side of the McDonald's coffee cups that the coffee is hot. (Maybe that's not a good example, it IS hot.) Anyway, radar is not a new technology. Is the danger real? Or is it a theoretical danger? With all the boats in a busy marina with their arrays spinning and all of us looking at them admiringly... Are we risking our vision?

I went with the stern mount but will plan on moving it to the mast. I don't want to be responsible for frying my family.


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## rikhall (Feb 7, 2008)

Vitesse473 said:


> When I see something like this in the front of the Raymarine users guide,


Please - I am not in favour of turning on your radar and sitting on the raydome or anything of the sort.

But, the warning in the manual has about as much weight with me as the warning on the take-out cup of coffee that says

"*Danger - may contain hot liquids!*"

Duh!

Too many lawyers, not enough somethings. 

I helped my buddy bring his first power boat from where he bought it to where he lives. The first time I stood at the helm to bring it into the dock for him, and the radar was on, it made my hearing aide beep. I looked around and there was the radome on the arch - about eye level and about ten inches from my head.

I quickly sat down and let my buddy take it into the harbor. I figured it was about time he learned to dock his own darn boat!

Rik


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## Vitesse473 (Mar 16, 2008)

jbondy said:


> With all the boats in a busy marina with their arrays spinning and all of us looking at them admiringly... Are we risking our vision?


No boat owner should have his/her radar on in a marina. It's bad for the seagulls, and equally bad for the equipment to run with all that clutter around. Atleast that's what my technician said.

I just thought it was odd that the manual specifically stated damage to the eyes. That means they noted something specific during testing and qualification. Probably using rats or pigs as subjects.


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## DwayneSpeer (Oct 12, 2003)

I have a stern mount pole you can have for next to nothing but the shipping may be prohibitive and you most assuredly will have to modify the lower end to fit your boat. If you want it I can send photos.

I use a self leveling system that attaches to a small pole run up next to my rear stay. It works well for me.


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## Valiente (Jun 16, 2006)

Cruisingdad said:


> I do not think it is a hijack as it directly relates to the placement of the dome.
> 
> I honestly do not believe anyone knows whether it is harmful or not. I think there are a lot of guesses, but that is it. I tell you that it does bother me - real or imaginary. I have always heard that it is good practice to turn your radar off before entering a marina and to never look at a dome/array while it is running. Now, is there scientific proof that it will hurt you?? I doubt anyone has done a study of it. The cost of doing such a study would be extraordinary and you can be certain that a manufacturer of Radars sure won't support it. So, you are stuck with making your decision based on folklore and old wives tales, I guess.
> 
> ...


I do not definitely know better, but I recall a scene from the Jerzy Kosinski novel "Cockpit", where the sadistic main character convinces a woman he is photographing to stand in front of a fighter jet's running radar in order to give her a cancer-inducing dose of radiation...

I later found out that was implausible, but have always resisted the idea of voluntarily putting my body in front of a running radome!


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## thekeip (Aug 8, 2007)

A 4 kw radar puts out about the same or less average power as your 25w vhf on low power. They pose no hazard at all in normal circumstances. Don't tempt fate however, and avoid long exposure if beam is at eye or gonad level. A 60 kw radar is another matter altogether. The multi megawatt military radars can do serious damage.
Howard Keiper
Berkeley


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## Talisman66 (Jul 18, 2007)

Sounds like a case for "Myth Busters" .


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## RanAweigh (Jan 16, 2009)

Engineering safety notice:
Never look into the wave guide with your good eye.


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## rikhall (Feb 7, 2008)

Talisman66 said:


> Sounds like a case for "Myth Busters" .


Too funny! I thought the exact same thing!

Watching them I now know:

not to try and clean a cement truck with dynamite
cell phones do not affect navigation systems on planes
you can't shoot a lock off a door with a pistol 
and cell phones can not cause gasoline to blow up.
Your post made me smile! 

Rik


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## SteveCox (Jul 12, 2006)

*Radar hazards*

When I was in the Navy this came under the heading of HERP (Hazards of Electromagnetic Radiation to Personnel) and along with HERO (Ordanance) and HERF (Fuel) made for some very complicated and boring reading. If you want to know what damage radar can do find and watch the video of the disaster on USS Forrestal. Radar can damage people mostly in the areas of the eyes and the testicles. Its' danger changes however based on dwell time, output power, beam width, distance from the antenna, frequency and a whole host of other factors. While it's not a good idea to sit on the radome to keep warm on a chilly day in most cases the radar for our boats does not pose a health risk due primarily to their low power. As long as you are not going to be at eye level with it at a distance of six feet or so during normal operation you should be fine. BTW the warning from Raytheon is accurate though on the conservative side of things.


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