Should sailboat radars be leveled, and if so how?


This entry is inspired by Edson’s Miami introduction of a Manual Radar Leveling Kit that looks neat to me. I’ve seen pole mounts like this before–either custom fabricated or made by less familiar companies like Garhauer–and they struck me as a simple and economical way to deal with the issue of decreased radar performance due to boat heel. But before discussing the merits of manual (or electric) leveling mechanisms versus the many self-leveling mounts, I probably ought to address the fact that some sailors reject the whole notion of radar leveling as hokum!…

For instance, I found this emphatic statement on “I NOTICED NO DISCERNIBLE DIFFERENCE BETWEEN THE QUESTUS {self-leveling} PERFORMANCE AND THE CONVENTIONAL POLE MOUNT!!!” And I’m pretty sure it was written by RC Collins, the highly reliable Compass Marine guy I wrote about recently. But it seems obvious to me that tilt must degrade radar perfomance to some degree. That’s because radar is designed for maximum performance when aligned to the horizon and that familiar figure of 25 degrees vertical beam width is really just a definition of where the ever-diminishing signal return reaches a certain threshold as the array tilts away from the horizon (as recently discussed on the forum). I think this means that even a little tilt has some effect though it also means that a radar will still paint some targets even when well beyond that confusing 12.5 degrees on either side of horizon figure. (The vagueness of radar beam direction is also worth understanding in regard to radiation dangers).
   At any rate, I’ve never tested my understanding of the radar tilt issue, but thankfully the good folks at Yachting Monthly did. The article itself is posted at Scanstrut (PDF) and there’s a YM YouTube video that yielded those screens below. I wasn’t surprised to see noticeable target degradation every 5 degrees from 0 to 30, particularly on the high and low sides of the boat, but at lower angles the issue isn’t completely obvious and neither is the solution…


Well, there certainly seem to be lots of self-leveling radar mounts for poles, masts, and even backstays. Besides the usual suspects like Scanstrut and PYI SeaView (gear below), there are even two small companies apparently both founded by sailor engineers with their own self-leveling designs, Questus and Waltz Manufacturing. I don’t know how all these designs vary in cost and performance, but I have heard that one overall concern is cable wear and, in fact, I’m told that’s why Edson has never ventured into gimbaled mounts. I noticed too the Practical Sailor quote (see Questus site) that goes like this; “The hooker in gimbaling is how to prevent the device and the antenna from swinging freely. A sailboat is an engineering laboratory devoted to controlling movement.”
   True that!  Which is one reason I like the tilt and lock design of the Edson manual mechanism (especially when the extra, or upgrade, cost is only $450 or $490, depending on pole size). Then again adjusting it could be a real hassle if you were short tacking in nasty conditions. I guess it really depends how you sail and what you’re willing to put up with. And ignoring the leveling issue does not seem an unreasonable choice, either, though I think anyone using radar while heeling ought to aware of the possible performance loss. Any sailors out there with experience or opinions on this subject?


Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

34 Responses

  1. Ben Ellison Ben Ellison says:

    Slightly off topic but it seems strange that immediately after finishing this entry I learned about an upside down Raymarine radar install on a 246-foot Zeppelin airship. Check out the photo album:

  2. Anonymous says:

    Isn’t a lot of most critical radar use for a smaller sailboat in relatively calm conditions when a sailboat is moving slowly in poor visibility conditions or at night and not hauling along at 6+ knots on a beam reach heeled 30 degrees? Those who want to do the latter have access to appropriate tilting solutions but I can see why a lot of the smaller sailboat users do not feel its a critical need with AIS now available to indicate the presence of much larger or faster traffic.
    On a sailboat, to the extent you can hold 10-20+ speeds in less than good visibility requiring good radar coverage and hold the antenna 40′ high so the beam clears the swell typical of winds that will product 10+ speeds it makes more sense to tilt the antenna in almost all cases.

  3. Larry Brandt says:

    An interesting topic, especially for this radar instructor who has a non-leveling Raymarine mounted above the spreaders. I’ll have to find the YM article. I’m always ready to learn something new. YM does impressive work.
    I chose the non-leveling option because I wanted the scanner to be mounted high, not so much for range, but for simplicity and radiation safety. I also didn’t want the mass of a scanner swinging that high on the mast.
    I am very concerned about radiation exposure, particularly the potential for ionization that might someday be determined to be carcinogenic. I have found no studies that deal with this aspect of x-band radiation, although my ‘common sense’ – or my imagination – tells me that bombarding atoms with pulses of 2kw or more might be able to ‘dislodge’ an electron. (My boss is a physicist, maybe I should ask him if my interpretation is valid.)
    As a previous post noted, in calm conditions leveling is redundant. In my Pacific Northwest experience that’s generally how I use radar…motoring through Rich Passage in 400 ft visibility, for example. In a seaway, though, height of the scanner is your friend, and as the YM article seems to indicate, perhaps leveling is as well.

  4. grumpy_o_g says:

    Theoretically a 2KW pulse could dislodge an electron but it’s not that likely to do much damage or we wouldn’t to build things like the LHC at CERN I guess. Radar’s been around for about 70 years now so it’s not the same as the cell ‘phone issue really. I would have thought a trend would have been detected amongst servicemen or other workers how spent a large amount of their lives near radar antennae (airports for example).
    I agree with Anonymous’s comment about heel. If I’m thrashing along at a significant angle I’m probably more worried about hanging on than looking at the radar screen. The only exception to that would be if I was spotting weather cells or possibly checking a radar fix, neither of which normally involve small targets. It would be interesting to see the actual transmit and receive radiation pattern polars for some of the small leisure sets. The manufacturers must have them though I have no idea whether or not they would release them. On a lot of the more basic sets I worked on the maximum range was actually either side of the centreline, not straight ahead.

  5. Dan Corcoran (b393capt) says:

    I am not a fan of self leveling mechanisms at the moment. I had them come loose on both my return trips from Maine as the screws worked themselves loose, and left my radar dangling. I am seriously thinking of not letting there be a third time (Thank You Raymarine for considering that just a minor repair, despite half the radome exterior missing and the cable ripped out !!).
    A manual tilting system just might be the ticket for me, but I am uncertain of that also. I don’t find myself heeled over that often in the kind of bad weather that would keep my eyes peeled on the radar.
    With Sirius weather radar on board I have tended to be very willing to go out in iffy weather, and when that bad weather comes calling I will more likely be motoring to safety during that calm before the storm.
    Of the many times I have been in fog or sailing at night and watching the radar, the wind was light, limiting the heel to 8-12 degrees at most.

  6. Ben Ellison Ben Ellison says:

    Larry, the full YM article PDF is under that “posted at Scanstrut (PDF)” link above, and both it and another article about self-leveler testing are downloadable here:

  7. SG says:

    We have a Questus unit on our backstay. We have used it for 13 seasons with good results. We have had 2 4KW Furuno units over that time. We replaced the radar solely to upgrade the system. I’ve been very happy with the reception of the system.
    Of course, it’s hard to compare the system vs. a fixed mount of the same height. But I have no complaints with the Questus. The extension tube for the Questus over the Navtec hydraulics puts the radar about 12′, or so, up above the water. We have several antennas, a cockpit flood, as well as the radar dome on the Questus.
    The only concern is that IF you have a hydraulic backstay (which we do), do not loosen it too much when the boat is in the slip or on a mooring. The Questus causes wear on the seals that can largely be avoided by keeping a moderate tension on the backstay.
    I found this out the hard way by having to have the seals rebuilt. ;^))).

  8. Richard C says:

    One thing I learned from my wayward youth spent racing sports cars is how to assemble mechanical fasteners. Every machined screw I put together has “Loctite” Blue or Red applied to the threads. On the boat, if above my arms reach or mounted on the mast I use “Red”. Following this rule should prevent a failure like what you experienced returning from Maine.
    Also, I have had both fixed mast mounted radar and finally a Scanstrut self leveling mast mounted radar. In my opinion, the Scanstrut is worth every penny. The fixed mount radar was unusable when sailing at night and heeled over. The radar signal was either reading the sky or the water alongside the boat. I guess if you never plan on using the radar while sailing in clear conditions a fixed mast mount is perfectly fine, but this limits the value of using radar to measure distances between you and a visual target at night while going to weather. It doesn’t have to be foggy out for radar so why limit such an expensive devices usefulness.

  9. Matt Marsh says:

    In the X-band (8-12 GHZ, 3.75-2.5 cm), each photon has an energy of hv = (4.14E-15 eV/Hz * 10 GHz) = 4E-5 eV.
    It’s the photon energy that determines whether it’s ionizing radiation. The intensity doesn’t matter. The threshold is roughly 10 eV, which is about 10 times higher than visible light and 250,000 times higher than X-band radar. (For comparison, the radiotherapy machines I use in my research run at 1 million to 18 million eV.) Radar cannot strip electrons from their atoms, period.
    The health risks from exposure to microwave radiation are mainly due to tissue heating. If the body absorbs RF energy faster than it can dissipate the heat, cells can be damaged by hyperthermia. This is where “minimum safe distance” rules for radar come from, and why it’s a bad idea to mount a pulse radar at eye level (and also why low-wattage FMCW radars, i.e. Navico Broadband, are human-safe at zero feet). There’s a fair bit of complex literature on this, but it basically boils down to minimizing tissue heating.

  10. Ben Ellison Ben Ellison says:

    Fascinating, Matt, except that it tempts me to go way off topic. But maybe others will be interested, especially Larry. In Maine, like California, there’s a fairly strong movement against “smart meters” which at least here use meshed WiFi. Frankly I thought the concerns farfetched but now a group called The American Academy of Environmental Medicine (AAEM) has called for a moratorium on them, citing “many modern studies show
    metabolic and genomic damage from RF and ELF exposures below the level of intensity which heats tissues.”
    This seems the most reputable endorsement of the anti smart meter movement yet, and I’d appreciate your thoughts.

  11. Peter says:

    Another advantage for catamarans!!!
    A small one I agree.

  12. Dan Corcoran (b393capt) says:

    The concerns are far fetched Ben.
    1) Matt is right on the money. At these frequencies the only effect is to heat body tissue, and eye-level isn’t an issue either. Although our eyes are much less able to dissipate heat than other tissues in our bodies, the safe limits of exposure as set by the government is wildly over cautious. In an earlier thread someone did the math to back up a statement that the amount of heat is insignificant from consumer boat radar. Something about 24 total watts average power spread out over 360 degrees (spinning radar) on one plane and 22 degrees on another. That isn’t even enough energy per cm square to make the radar case perceptively warm to the touch in any one spot, the amount of power that intersects with our eyes is miniscule. As I wrote on another thread lets all go hug our radars, show our appreciation, and show we are not afraid anymore. There are many other things to be afraid of …
    2) and it isn’t Wi-Fi. The AAEM position is incorrect when applied to Wi-Fi, Radar, or any non-ionizing radiation. The statement “many modern studies show metabolic and genomic damage from RF and ELF exposures below the level of intensity which heats tissues” is inclusive of too many frequency ranges where it is entirely untrue. Just because a chest x-ray is harmful even though you cannot perceive the heat during the exposure, doesn’t make it ok to lump Wi-Fi or radar frequencies into the mix. Chest x-rays are an example of ionizing radiation.
    3) On the AAEM web site they include a wide range of frequencies that trouble them including both ionizing and non-ionizing, quote “radio frequency (RF – 3 KHz – 300 GHz) or extremely low frequency (ELF – 0 – 300 Hz)”. That’s just about every frequency.
    AAEM is basically including every frequency you can think of with the exception of frequencies we can hear with human ears above middle “C” on a piano and below the limits of human hearing. Why stop at warning us about Wi-Fi at our power meter? Maybe warn us that our entire home should not be connected to the power grid.

  13. Matt Marsh says:

    I don’t want to make this thread drift too far from the original topic. (Radome levelling mounts, right?) But the health effects issue is too interesting to pass up. There is a lot we don’t know about the effects of high-intensity, low-energy radiation, but we do have a pretty good basis for saying the health effects of low-intensity, low-energy radiation are negligible.
    The Wi-Fi band (2.4 GHz) is of interest because it’s right at the resonance frequency of liquid water. This is why microwave ovens use the same band, and why it was unlicensed in the first place: as soon as 2.4GHz RF hits water (fog, dew, leaves, food, people) it’s mostly absorbed, and the band was therefore more or less useless until the advent of modern signal processing.
    All EM waves deposit some energy in whatever material they go through. What we get from man-made RF is pretty tiny compared to the ~1 kW/m2 flux of ~1 eV radiation we get whenever we’re outdoors on a nice day. (It’s called sunlight.)
    Until you get over a few eV (ultraviolet), all that this energy can do is vibrate the electrons a bit. (Above about 10 eV, or UVC band, you start breaking chemical bonds and ejecting electrons.) RF engineers know this, and design stuff so that it never becomes an issue. For example: MRI machines constantly track the RF energy they’ve deposited in the patient, and have an interlock that compares this value to known rates of heat dissipation in various tissues. And one of the reasons that WiFi is only ~50 milliwatts is- you guessed it- so that it can’t dump appreciable amounts of heat in human tissue. If you put one of those 2 watt WiFi boosters on your lap, then yes, it will heat your nuts up faster than they can cool off.
    Most of the studies that the TV news cites as saying “News flash, $RF_device$ causes cancer” actually say things like “We might have found a slight correlation, in the top few percent of cellphone users, between the side they hold their phone on and the side of the head that certain rare brain tumours form on”. This is where the microwaves-are-a-class-2b-possible-carcinogen talk comes from. You can’t say for sure that it’s not an issue, so you say “be careful” and hope that more data is coming.
    If you want to avoid health problems from non-ionizing radiation, you should move to a remote rural area with no radio or TV reception, throw out any electronics that use wireless communications, switching power supplies, or inductive motors (i.e. all phones, all computers, all cordless devices, all major appliances), wrap all your power lines in Faraday-cage conduits, and never go outdoors without your foil-lined burqua.

  14. Matt Marsh says:

    Re. the anti-smart meter movement. They have many legitimate concerns (the inability of some lower-quality meters to accurately measure and report data, for example, or the privacy concerns when data about your habits is amassed by a large bureaucratic entity), but IMHO, RF emissions from the meters are not among the legitimate concerns.

  15. Dan Corcoran (b393capt) says:

    Well said Matt

  16. David Marchand says:

    I have owned sailboats with self leveling- Questus, manual levelin- Garhaeur and fixed mounts.
    Yes you do get target degradation off to the side of your boat when heeled. But does it really matter? No, not really..
    I use my radar in fog- no wind, therefore no heel and at night- lower wind. At night there is plenty of time to watch for the return even if it is fading in and out due to heeling. And almost everything I am interested in is in front of me- about 45 degrees to the right or left and these azmuths are hardly affected by heel.
    So leveling is nice to have, but not essential. There are more important things to spend your boat bucks on.

  17. Ben Ellison Ben Ellison says:

    Thanks very much, Matt. There are some folks around here I’d like to email that last paragraph to, though I probably won’t. But there is a particular waster of town meeting time and frightener of citizens who I will picture from this time forth in a foil-lined burqua!
    Sorry to sidetrack the thread, all, but I did get upset about this anti-smart meter thing last fall. It seemed like many intelligent people — often environmentalists who might otherwise appreciate what smart metering could do for us — were ready to believe any negative theory about them.
    What, for instance, can really be detected about the residents of a building by measuring current flow versus time? A grow house, maybe, but then again the police might find a Bitcoin miner instead ( ). I talked to the contractor who changed my meter and learned he had to take special training on how to deal with irate home owners. Crazy world; end rant.

  18. Doug says:

    Back to the original topic. We installed a Simrad Broadband radar 2 years ago. First installation was on the split backstay with a gimbaled mount from The mount is dirt simple and works beautifully. But there was too much side to side wobble without a pole. Got several images instead of one. Last year we installed a radar mast (from the same source) on the port quarter and traded the backstay mount for a pole mount. Problem solved.

  19. Chris s/v/ Pelican says:

    For those of you that say there is little need for leveling since your primary use is during calm times to navigate fog or at night… when you need it, you need it. On our way South a while back, we rounded Cape Fear in the Carolina’s at 2am. A low pressure front came in faster than expected and pushed winds to 40-45kts and seas to 14′-18’… we were heavily reefed, but still heeled over at 20 degrees or so as the wind was close to the nose… we hightailed it for the Cape Fear River but had to deal with a plethora of shipping traffic in the area.
    First observation – loved having our radome up high on the mast so we could see over the majority of waves. I know it’s nice to keep the weight low, but if we had a pole mounted unit it would have been useless except when we crested the waves. Second observation – we could see very little to either side of us because of the heel, so cross-path shipping traffic was difficult to spot. A gimballed mount would have radically improved our situational awareness. Third observation (and nothing to do with the Radar)… thank goodness we had hard buttons and a knob vs. a touchscreen on our chartplotter/radar as there would have been no way to adjust our waypoints or zoom the radar etc. as we were pounding through the waves. There were a million other lessons learned too.. like how nice AIS would have been to have… We did plenty of Securite calls, talked to numerous commercial vessels that were happy to know where we were and also talked to vessel traffic control to ensure others knew our position during this time. It was nasty…
    We had several such experiences and, before our next cruise, I’ll be looking heavily into gimballed mounts. I would now consider it a piece of safety gear.

  20. Ben,
    Yes those were my comments on I spent a lot of time reading the data, looking at the specs and the “why’s” for why I “had” to have a self leveler before I bought it. Having not ever had one I decided this was a new “must have” item.
    The first season I spent a good deal of time analyzing the performance, not just in fog but on clear days when I could compare targets. I would lock it so it could not self level and see what I got then unlock it and see if I could tell a difference. There were some slight differences at high degrees of heel but I am a “flatter is faster” kind of guy so the level of heel was not as significant contributor to harming the performance as I thought it would be.
    When it came time to do radar on the next boat I simply chose not to spend the money on a self leveler as I could discern so little difference for the way we sail, that it was not worth the expense to me.
    Despite not going with another Questus self leveler, when we bought a new boat, the device is extremely well engineered, built and designed. I had no qualms about the quality what so ever I just do not feel it made a difference that was quantifiable in relation to the expense..

  21. Bob Austin says:

    I have cruised over 100,000 miles with radar on sailboats. For the most part cruisers try to sail down wind, or at least on beam reaches–and it is rare to have conditions beating into heavy weather, with limited visibility. (Exceptions might be going North up either the West Coast of the US or Europe). We had one radar up about 40 feet of the water on a mizzen mast, and the other about 14 feet off the water on a dedicated aft radar arch. I could not see much difference in heavy weather between the two. On the other hand, when you are in 40 foot seas, the radar is about the last thing your are concerned with.
    Fog usually is with minimal wind, and thus not much heeling. Night sailing, you are interested in other vessels–of all sizes. Near the coast it will be small open fishing boats; On passages it will be ships. Even heeling 30 degrees we could pick up ships at 10 miles–and track them adequately. Yes, the images were not as good, but adequate. I could not envision having to adjust a manual radar “pole” every few minutes as the angle of heel changed. There are too many other things to worry about.
    Add in now we have AIS, and FLIR–which was not available at affordable prices until the last few years.
    As for the medical aspect–as a physician, I have avoided the direct beam, and advised others to do so–but realistically there is minimal health hazard from recreational boat radar. The only potential exception is males and females of childbearing ages who sit just behind the mounted radar on the front side of a flying bridge. There is a slight but potential risk to the sperm and eggs that I would not want to take.

  22. Robert says:

    I am in the navy, when i got to my first ship there was many people that said those who stand a lookout watch under the radar would only have little girls when it came time to have children. at the time, while i had concerns about being under the radar, i paid this little mind. before i transferred off that ship every Bosunsmate that had kids all had little girls. over the last 12 years i have seen this to continue to be disturbingly true among anyone who works under or close proximity to radar. this is only observation and not a scientific study.

  23. Sandero says:

    Leveling radar mounts are the invention of someone who needed another expensive marine product to sell. The improvement in signal return is not significant or useful for far off targets. Someone with a radar will have AIS for locating ships… self leveling radar is no use for that unless they are damned close.
    Most use radar making way slowly because of poor visibility… and so there is little to no heel and the self leveling feature does nothing but swing about each tack and fatigue the cable. You didn’t bargain for that Questus… eh?

  24. Ben Ellison Ben Ellison says:

    “Leveling radar mounts are the invention of someone who needed another expensive marine product to sell.”
    Sigh. Once again we hear demonization of the marine industry by someone who substitutes a mean disposition for facts. Just reading this entry and comments is all that’s needed to realize that not one, not two, but THREE manufacturers of self-leveling radars are tiny companies founded by sailors who apparently felt they could design a better model.
    Does anyone besides Sandero think that the founders of Questus, Waltz Manufacturing, and Radar on the Level just came ashore and said something like this to themselves, “Hey, I could make some quick bucks by engineering a dampened radar gimbal system and selling a few of them to fellow sailors, even though they’re useless!”?

  25. Christopher says:

    I suggest an experiment. Get in one’s car, cock one’s head to the left or right 15 degrees and drive through a moderately busy village one hasn’t been to before — wearing Eskimo slit sunglasses. One is not allowed to make any adjustment to one’s head.
    After one drive, I suggest one will be trolling the internet for a good price on head levelers.

  26. Randy says:

    Fixed-mount versus self-leveling was a major discussion for my team and our customers when we were selling and installing numerous radars in Annapolis, a major sailing center. We opted almost exclusively for fixed-mount, and mostly on a post rather than up at the spreaders. In my offshore experiences over the years, when in reasonable wind strengths but heeling a bit going upwind, we always steered off the wind for a few moments which brought the boat more upright (without easing sheets!), took a look around on the radar screen, then steered the boat back to her proper upwind angle. Again, all without easing or trimming the sails.
    I had one particular couple who related radar performance comparisons with a Questus mount before being dismasted to subsequent performance with the same radar set after reinstallation on a custom stern post. Theirs was a big racing boat out of San Francisco, and they were quite convinced they had superior radar images after remounting on the post. I contacted several of our manufacturers’ radar techs to see if there was a technical answer behind this, but nobody could offer anything in how radar works that provided any hint of explanation. A previous writer mentioned wobble on a backstay mount as being a factor in painting multiple images, so maybe it was similar to that.

  27. Larry Brandt says:

    Very interesting thread. (Shows you what I know about physics!) But levelers are a topic in the courses I teach, so all of this first hand perspective is valuable. Thanks, all. And thanks also, Ben, for the link to the article.

  28. Sandero says:

    The motivation for innovation is often making a buck. Isn’t that what the capitalists always say? My point is that there is not enough bang for the buck with the self leveling mounting. That is the performance improvement is rather marginal in MOST conditions. It has no impact on targets from about 11 to 1 and from 5 to 7 at all. The returns on targets from 1–2 o’clock might see some marginal improvement. The real improvement to be seen is for targets on the beam. That would be 1 out of 6 point of the compass. The you need to consider how heeled the vessel is and the vertical shape of the radar signal. I suppose they vary but it not a thin slice as a rotating lighthouse beam is… with all the energy closely focused on the horizon. The radar beam spread is going to be 20°… so 10% of heel is covered. If the beam angle is 30° than you are covered up to 15° of heel. And 15° is about as much as you want to be.
    Frankly I just don’t see where the improvement is to be found for 95% of one’s sailing.
    And what about the down side of wire fatigue of the cable cycling back and forth every time you tack?
    Are these things clever and cool looking? Sure. But are they worth it? No.

  29. Ben Ellison Ben Ellison says:

    Nope, that’s not what the “the capitalists always say.” Neither is it always how economists and business experts describe innovative companies.
    Also, I’m beginning to think you didn’t actually read the entry or other comments. A radar’s claimed vertical beam width does NOT mean it works as well at 10 degrees tilt as it does at 0 degrees. I even linked to a test video that indicates that beyond doubt, I think.
    But the main thing is how can you say that radar leveling isn’t worth it when experienced sailors who’ve tried it both ways say it is, right here in this thread? I just don’t get that.
    I think it’s pretty obvious that what I surmised in the entry — “it really depends how you sail and what you’re willing to put up with” — is true.

  30. Dan Corcoran (b393capt) says:

    Sandero wrote “It has no impact on targets from about 11 to 1 and from 5 to 7 at all. The returns on targets from 1–2 o’clock might see some marginal improvement. The real improvement to be seen is for targets on the beam. That would be 1 out of 6 point of the compass”
    You lost me on that analogy.
    #1 While I might agree between 11-1 and 5-7 have no value, and maybe take that all the way to 10:30-1:30, and between 4:30-7:30, that leaves a full 50% of the compass rose for which there is significant benefit.
    #2 Unless I am sailing on flat seas, I need the +/- 11% capability of the radar just to deal with the sailboat rolling on the sea. Even if healed 8% (not unreasonable), the radar performance is going to fall off very hard going through any significant seas. On each roll 25% of the radar beam is going to be radiated right into the sky, and 25% into the sea, for two or four radar sweeps on every roll. Most tracking and filtering features on our radars are going to not recognize a target that is absent for 2 or more radar sweeps and then fail to track or enhance the contact.
    My comments of limited value are for “self” leveling. As for manually leveling, I am a big fan of that feature, and will probably do that next time around, which might be less than a couple of weeks from now.

  31. John Harries says:

    Hi Ben,
    We have had a leveling device since 1992 on our McCurdy custom cutter, “Morgan’s Cloud”. It was made by Edson and is based on a motor boat trim tab actuator. The control is next to the helm. I replaced the unit last year with another trim tab actuator and pump from Bennet (any one will do) because the old one was leaking and no longer made.
    I fitted the original unit after we very nearly came to a nasty end on a foggy afternoon off Lunenburg, Nova Scotia. A large steel dragger doing at least 10 knots appeared out of the thick fog at a few hundred feet off the port beam heading straight for us. Yes, I know it was our right of way, but with big steel draggers, that is scant comfort. It was pure luck, or maybe a sixth sense, that made me look up from my navigation at just the right moment to see him just as he appeared. Or perhaps I heard him over the sound of the wind and sea (it was blowing 20 knots true) without realizing it.
    We were on the wind on port tack and healed at about 20 degrees. I had checked the radar just moments before and never saw him. Our radar was in good condition with a new magnatron, properly tuned and was picking up targets fore and aft. We just managed to avoid each other, but it was as close as I have ever come to a collision.
    Having sailed for 20 years and some 80,000 miles in areas that have the highest incidence of fog in the North Atlantic and repeatedly watched targets appear as we level the radar after each tack, I can state categorically that leveling the radar is a must for safe sailing in fog.
    I have also never had a problem with the cable. Our current cable for our Furuno 1830 is fourteen years old. I would not use a self leveling device because of the repeated working of the cable in a seaway.

  32. LeaScotia says:

    I installed a Radar on the Level for a 2 year trip down the West Coast, through the Panama Canal and on up through the Caribbean to Florida. The backstay mounted pole was easy to install and is good quality. Biggest drawback we had? The darned 4kw radome would swing back and forth running downwind in big seas – lots of wear and noise – I ended up tying it off with a line. We did do some beating but I found the mount would hang on occasion so I had to level it with a boat hook periodically. We also have a fixed mast mount radar on the mast and in my experience the self-leveling unit on the backstay was just not worth the hassle.
    Just my 2 cents. I still have it but would probably go with a pole if I had to do it again.

  33. Dan Corcoran (b393capt) says:

    With my previous bad experience with a self leveler on the mast, I was on course and speed to buy a stern pole with a fixed mount for our radar.
    But, this entry and many supportive comments reminded me why I bought a self leveler originally, and I caved this weekend at Defender Warehouse Sale and annual Vendor Exhibition and bought a stern radar pole with the self leveling.
    Very timely entry.

  34. Mic says:

    I was just re-reading this thread and following some of the links. FYI, it appears that Radar On The Level no longer has a web presence. 🙁 -Mic

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