yacht radar reflector test

11 radar reflectors tested : Not all models are really easy to see

Alexander Worms

 ·  14.05.2023

This is how we tested

11 radar reflectors in the test: the results, how radar reflectors work, radar technology: broadband or magnetron radar.

Who needs a passive radar reflector in the age of AIS? Thanks to modern electronics, you are highly visible on the screens, certainly on those of commercial shipping. Well, the question seems justified at first glance. On closer inspection, however, the answer is clear: everyone who is on the water with commercial shipping needs such a device. This is because AIS technology is dependent on a power supply - if this fails, the yacht is no longer visible. Passive radar reflectors work at all times. What's more, there are some areas, such as the Waddenzee in the Netherlands, where a radar reflector is simply mandatory.

Not much has changed in terms of products in recent years. On the market, the Tin cube which Tubes and the Echomax . There was also a device called Trilens. This reflector is now sold under the name 3Lenzz offered again.

But how good is the performance of the reflectors in practice and when it is not a question of being seen by large devices on the bridge of a commercial vessel, but by a less powerful yacht radar? First of all, it is difficult to make generalisations and the conclusions must be formulated precisely.

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The problem is explained using an example: the 3Lenzz consists of three spheres that are mounted at an angle of 120 degrees to each other. A test by the British coastguard had already shown that it has a blind spot every 120 degrees. If radar signals hit this blind spot, the echo on the screen disappears. All reflectors have such blind spots, to a greater or lesser extent. During our test, we recognised the 3Lenzz by the fact that the echo was clearly visible, disappeared for a few orbits and then reappeared. The test boat was obviously close to a blind spot on the reflector. In practice, this would be the case when approaching with an exact bearing, for example when a ship is travelling towards an anchor berth that is not swinging. However, if the angle between the two changes by just a few degrees, there is an echo.

The conclusion that it doesn't work well because it was sometimes poorly visible in the test would not be the whole truth. The echoes were clear when measured from a different position. The conclusion is therefore that the 3Lenzz delivers good results with changing courses of approach and only shows weaknesses at three points on the full circle.

To simulate the situation on a sailing boat, we measured each reflector vertically and at an angle of 30 degrees. Here, too, some models showed weaknesses. In particular, the models with an already small reflective surface sometimes collapsed significantly. However, even the weakest reflector ensured that our test pontoon appeared on the radar screen.

The echo of each reflector was measured a total of eight times - from a distance of 0.5 and 1.5 nautical miles, vertically and at an angle of 30 degrees, using a modern broadband radar and a conventional magnetron radar. The displays of the broadband radars are shown in the individual test images. Measurements were taken from a motorboat on which both antennas were installed. The reflectors were installed at a height of around three metres on a pontoon on a wooden mast, which could also be tilted. The results were then saved using a screenshot on the Garmin devices used; these were radars commonly used on yachts. We optimised the settings of the radar unit for the medium-sized sheet metal reflector and did not change them in the further course of the test in order to ensure the same conditions for all reflectors. We only tested the two inflatable reflectors in an upright position, as these are usually suspended.

Plastimo sheet metal small

At close range, it is always easily recognisable on both devices. At greater distances, it is not visible in a vertical position; echoes only became visible when the mast was tilted. For an optimum echo, the reflector must be mounted in the rain catcher position, but this can only be the case either in an upright or tilted (in the test) position. Mounting is difficult, the metal sheets are sharp-edged.

• Weight: 0.45 kg
• Reflective surface, total: 3.0 m²
• Price: 33,92 €
• Distribution: Bukh Bremen
• Dimensions: 215 x 215 x 280 mm
• Rating: ***

Plastimo sheet metal RORC

The big brother is consistently easier to recognise on both devices at close range. From a greater distance, the solid-state radar struggles with reproduction. On the radar, the reflector cannot be seen in an upright position; when the boat is heeled over, it blends in with the tug echo. The reflector is very large. There is no opening on the inside to feed a stage through; the installation of the reflector on a sailing boat is unclear.

• Weight: 1.0 kg
• Reflective surface, total: 7.0 m²
• Price: 52,48 €
• Dimensions: 340 x 340 x 470 mm

Echomax EM 12

Good visibility at both distances. A rather weak echo when measured upright on the magnetron radar. At the greater distance, the reflector also clearly stands out from the echo of the tug. Mounting is easy, a foot helps with mounting on the spreader, for example. A spherical cut-out in the centre makes mounting on the stay easier as it can be threaded through. The plates are not sharp-edged.

• Weight: 0.73 kg
• Reflective surface, total: 5.5 m²
• Price: 80,50 €
• Distribution: Lindemann KG
• Dimensions: 360 mm

The rod is only visible as an echo from a short distance, but it is always equally good, regardless of whether it is vertical or inclined. At greater distances, it is invisible on the semiconductor radar. Only the magnetron radar can detect an echo in a vertical position. The reflector is lightweight and easy to install. However, it is more expensive than the similarly performing Plastimo tube. A base for mounting on deck is available.

• Weight: 0.38 kg
• Reflective surface, total: 2.0 m²
• Price: 49 € (as of 8/2022)
• Distribution: Lankhorst Hohorst
• Dimensions: 50 x 570 mm

Plastimo pipe small

At close range, the Plastimo tube is reasonably visible, but the echoes are visibly weaker compared to the Mobri tube. At greater distances, an echo is only recognisable in a vertical position and on the semiconductor radar. The tube therefore reacts sensitively to heeling. Some of the aluminium plates inside are severely bent and not aligned at right angles. Lightest reflector in the test field.

• Weight: 0.25 kg
• Reflective surface, total. 2,0 m²
• Price. 36,53 €
• Dimensions: 50 x 580 mm

Same picture as its little brother: no visibility at a distance of 1.5 nautical miles. Only the magnetron radar in vertical position shows a slight echo. However, the Mobri is clearly visible at close range. The twice as large reflective surface compared to the smaller version does not result in a better echo. The extra weight and price are therefore not worth it. Also available with base.

• Weight: 0.88 kg
• Reflective surface, total: 4.0 m²
• Price: € 95 (as of 8/2022)
• Dimensions: 100 x 590 mm

Plastimo pipe large

The same picture as with the competitors in tube form: At short distances, the image is usually good, although very small echoes occur with magnetron radar; at greater distances, they are almost completely invisible. Here too, the larger reflective surface does not result in a better echo. The aluminium plates inside are also bent and not mounted at right angles. The workmanship does not look very high quality due to the burrs on the plastic.

• Weight: 0.90 kg
• Price: 62,83 €

Echomax 230 BR

The very large device is the only reflector that produces an echo under all conditions and regardless of the radar technology. However, these are sometimes rather weak, especially if the reflector is tilted. If the reflector is upright, very good echoes are consistently displayed. The Echomax is very large and heavy, the required mounting bracket costs extra, but is very solid. Rather for large ships.

• Weight: 2.5 kg
• Reflective surface, total: 24 m²
• Price: 301,07 €
• Dimensions: 245 x 610 mm
• Evaluation: ****

The 3Lenzz shows consistently good echoes at short distances. At greater distances, reliable echoes are only visible when the device is mounted vertically. If the device is tilted, a strong echo is only visible about every third round, but it is reliably visible in the same place. This is probably a consequence of the three-part design, see running text. The 3Lenzz is the most expensive and heaviest reflector in the test.

• Price: 389 €
• Distribution: Northwest radio
• Dimensions: 300 x 300 x 150 mm

Echomax EM230i

Very good and clear echoes throughout thanks to the large projection surface. Due to the suspended mounting, the reflector is always aligned vertically, so no curved values were measured. Due to its low weight, it is the ideal addition for small cruisers who only want to use the reflector when necessary. As with the ball, we recommend replacing the reflector after five years. However, it is very expensive in comparison.

• Weight: 0.42 kg
• Reflective surface, total: 17 m²
• Price: 296 €
• Dimensions: 300 x 750 mm

Plastimo inflatable

Good visibility at short distances, barely visible at greater distances. As the ball always hangs vertically when it is hoisted on a flag halyard, for example, there were no measurements when tilted. Rather poor echoes despite the comparatively large reflective surface. Unfortunately, the ball was leaking, so that constant re-inflation was necessary. The reflector is very large and light when inflated. Expensive.

• Weight: 0.6 kg
• Reflective surface: 10 m²
• Price: 268,94 €
• Dimensions: 615 mm

It used to be like this: after the radar unit was switched on, it took quite a while for the first image to be taken. This was because the electron beam tube, the magnetron, had to heat up first. This took time and required a lot of energy. Operating the devices also swallowed up a lot of electricity. So, on long patrols in areas with little traffic, it was only allowed to carry out a sweep every few minutes. If nothing was seen, the device switched back to stand-by mode and only used the energy required to keep the tube at the right temperature.

Modern radar devices solve this differently. There, it is not tubes that generate the signal, but semiconductors. They can also generate signals of different wavelengths. As a result, the radar is available as soon as it is switched on and requires much less power. In addition, the radiation is significantly lower, which is good for the health of the people on board. A broadband or semiconductor radar generates roughly the same radiation as a smartphone. Due to the different wavelengths, the radar can generate even more information from the reflected signals. So-called Doppler radars quickly recognise whether an echo is approaching or moving away and in which direction it is doing so without the need for complex plotting. This makes it possible to calculate the point of closest approach and the time until then.

Most read in category Equipment

Which Radar Reflector?

Tri-lens – From what I understand this radar reflector offers some of the best all around performance for the price. Typically you will see these mounted to the face of the mast. This presents an inherent problem for us sailboat riggers; it is in the path of the jib which is inevitably going to try and wipe it off of the front of the mast. This is especially a problem on boats which utilize overlapping headsails, don’t have forward lower shrouds, don’t have a mast mounted radar and guard (as pictured above), have aft swept spreaders, or use a permanent Stay-sail stay to help protect this vulnerable part from getting knocked off. These reflectors have recently been modified with a second mounting bracket on top for a sturdier mount (not pictured). This second bracket has made us more confident in installing these, as there is a big difference in how sturdy the unit is. Keep in mind the plastic cover of these lenses are well built and therefore very heavy. You’ll want to make sure that you have taken every precaution to ensure that it won’t come crashing down on your head! Echo Master – The most tried and trued of all of the reflectors. Many will argue that even though this isn’t the “fairest of them all”, it works pretty darn well. Especially when mounted in the coined “catch rain position” (pictured above), using Davis’ Echomaster Hanging Mount , optional. The problem is how do you mount the thing without it flailing about like a wild, out-of-control disco ball. See the gallery below for how we achieve a good way for these to be mounted beneath the first set of spreaders…

Although there are many more products out there worth researching and we will gladly always explore new products and options, these are the brands that we have had most of our experience installing. Need more information or help installing a radar reflector? If in doubt, don’t forget to  Contact your local rigger for assistance.

Do you have any experiences with radar reflectors? Don’t forget to  Share your thoughts below and thanks for the read.

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23 Comments

Have you seen these https://www.leadingedgepower.com/shop/products/wind-turbines/le-v50-vertical-axis-wind-turbine-1013843.html They are a bit heavy, and need need strong brackets, a simple ‘guard’ could be made to protect the sail- but the spinning blades – besides producing power – are supposed to be highly effective in reflecting Radar signals.

Thanks for the useful article! Buying a boat equipped with a Mobri and will consider adding a tri-lens for passages. Also AIS is a must! Are you still giving away t-shirts? I’d love one if so.

Thanks for the read and the kind words Rory. We are OUT of shirts!! Sorry, I wish I had one for you. Keep checking in with us, we’re always getting new swag for giveaways.

Just a comment from another industry: I fly for the airlines and all jets these days are equipped with TCAS, or the traffic collision avoidance system. This is an active collision avoidance system where TCAS equipped aircraft talk to the installations on other aircraft sharing altitude and airspeed information. If the TCAS computer senses that it’s safe zone has been breached it will provide the two aircraft in question “traffic advisories” along with an audible warning. If no action is taken and the two jets continue to close on each other, a “resolution advisory” is issued giving the two pilots opposite avoidance instructions to avoid a crash. This has virtually eliminated midair collisions between commercial aircraft.

Of course, you have a little less time to see and react when the closure rate is 1000 knots, but it is a tremendous system.

Given my experience with TCAS, I’d really recommend an active collision avoidance system, particularly if you spend any time around commercial shipping regardless of the prevalance of fog in your area.

As far as trying to McGuyver something, I would think that the lids of tin cans would work better than tin foil. In fact, if you had a few of them and some reflective tape you could probably come up with an approximation of an Echomaster in a pinch.

Thanks for the comment.

There is a collision avoidance system for boats, and although this is good, many boaters are cheap. I like the tin can idea, going to do that. It is difficult enough to afford the basic safety gear. My step dad had no gps or electronics in his day. The fanciest piece of equipment he had besides his sextant was an oil lamp which he gave me for my boat. I use it whenever I feel like getting a headache. Many boats also have proximity alarms, etc. It pays to have as many of these safeties as possible. (as affordable) I have a good friend that sailed the oceans solo for very may years. He is in his 80’s and I just convinced him to get a GPS a few years ago. He also asked me to find him a woman online, so if you know of someone… My question would be, do any of these barrel or inflatable reflectors double as mast flotation in case of capsize?

Haha! I have my own troubles with that Alain. Even though the Firdell Blipper has a very buoyant look I wouldn’t trust it as my anti-capsize device. Perhaps that’s what any of these are good for. Seems rather controversial…this whole radar reflector business.

Thank you for the chuckle and for taking the time.

Yes the Echomaster is quite effective if hung in the RAIN CATCH ATTITUDE, that , despite your claim, is NOT shown. Hung as shown by one corner is a rain SHEDDING position! The reflector needs 2-3 attachments so a ‘ CUP’ is formed at the top…hence ‘rain catch position’. When hung this way the other reflecting surfaces of the side pockets are more likely to bounce the radar signal back to its source (acting like a prism) than a flat vertical plane which are unlikely to be square on to the signal source Tilting will make it worse where the rain catch angles will still work. Area is important as is the flatness of the surfaces and accurate corner assembly. Regards, Lew .

Thanks for commenting and all of your points. You are correct the gallery image depicted does not employ the “Catch Rain Position”. This is noted below the gallery collection, but it is a little hard to read, I will put it at the top. Thanks, this is once of the many reasons I encourage commentors. The generic product image from Echomaster does show the unit in this position. I will add an image caption. Davis actually makes a specific spring style hanging (instead of the bridle) that is rigged through the center of the Echomaster so that it can be hoisted in the coined “Catch Rain” position… this is also shown (if you look carefully) in the Echomaster product image in the article. On the Davis site, the “Catch Rain” hanging mount is described as…

“#153 Deluxe Hanging Echomaster Anodized aluminum plates. Comes with hanging mount system to suspend unit from mast or rigging in perfect “catch rain” position. Vinyl storage case included. #157 Surface Mount System can be purchased separately”

As the article suggests we are no experts on radar reflectors or their performance, but just wanted to speak to some of the more functional ways of rigging/installing the various products so that they do not interfere with boats sailing systems as well as provide safety for the crew below on decks. Therefore, it is our belief that once the reader chooses the radar reflector(s) and follows the manufacturers guidelines along with our points on mounting them to a sailboat mast, they will have a product that is not only functional but will provide the user with years of trouble free use.

Readers are always urged to get more product specific information directly form the manufacturer. You can get more information on how to properly execute the Echomaster here… .

Thanks for the read.

The Radar reflector is one element of the measures boat owners should take to ensure that they can see other marine traffic and most importantly be seen by other marine traffic. It is clear from the Qinetic report on radar reflectors following the tragic loss of the yacht Ouzo south of the Isle of Wight on the 20/21 August 2006 that boat owners need to select a radar reflector with the biggest possible reflecting area to ensure that they can be seen by radar equipped ships. Furthermore the report confirms that the performance of the Echomaster and Mobri is rather poor and states that poor solutions whilst giving owners piece of mind may in fact do little to improve the boat’s visibility on radar! Cost and ease of installation should be of no importance in the debate. Consequently I would select the Tri-Lens readar reflector if I was selecting a passive reflector but a much better option (confirmed by the Qinectic report) is an dual band (X and S) active reflector such as the Echomax Radar Target Enhances (Echomax Active XS) or the SEA-ME Dual Band which are highly recommended in the Qinetic report..

I have a Firdell Blipper in the top of my mast – above the forestay, so out of the way of any sail. It has been there for 20 years now so your comments on the brackets sound strange to me. I sail on the very busy North Sea and I have never heard of ships or coastguard stations unable to find me on their radar. As a matter of fact I have hardly ever had to alter course when crossing shipping lanes because the other ships see me long before I see them and it seems they think my boat is much bigger then it really is (only 22 ft). So I have great confidence in my Firdell Blipper and already have one handy to mount on my next boat.

It is good to hear a success story with one of these. As the article says there is much controversy surrounding the many different radar reflector options. These are just the view points as we’ve experienced them. Putting the reflector above the headstay is a great idea…probably why it has lasted so long and works so well. There is nothing to mess with it up there and from what I understand the higher the better.

In regards to performance we know really very little hence the three articles cited that conducted testing on the various products.

That’s a big reflector for such a small boat no? What type of 22′ sailboat is this?

Thank you for taking the time. ~T.R.C.

I build n deliver boats in the gulf of mexico north and south the echo master is always in my delivery bag i dont trust anything else even if the boat im delivering has one i put my spare up also i keep mine polished for better radar reflection

That’s a smart boat delivery captain in my book. Thanks for taking the time Rick!

The Canadian Coast Guard and Practical Sailor also did test years ago and the small tubular reflectors did very poorly. We formerly operated a charter fleet and I would never install a Plastimo or Mobri. After a strong wind one night, I came onto the float and found pieces of a tubular reflector which had shattered.

They are easy to mount, however virtually useless, especially when heeled. Viki. the bag of foil would be of no help. You need precise 90 degree corners to reflect the radar signal.

Thanks for the comment. No question on the Mobri having tested poorly, all three of the linked sites say so too. As I said we just like these from a rigging point of view. Perhaps mounting two, as we always do, would improve some of these test results? Also, in my experience these are usually improperly mounted….almost always, hence they can come crashing down; this is the case with anything though, right? Not a one, in ten years of rigging offshore boats has come crashing down at least unbeknownst to me ;-0) Remember, we feel the key with these is to have them installed on a diagonal shroud so that when the boat heels at least one of the reflectors sits in the vertical position. I believe when used in conjunction with and properly rigged Echomaster beneath the spreader, you are really increasing your chances of being seen. In our opinion, this combination is probably the best possible set up for double spreader masts with aft swept spreaders, overlapping headsails, forward lowers, mast mounted radars with guards, or inner forestays, to help protect the hardware from becoming dislodged or damaged by the tacking sail.

Modern boats with non-overlapping headsails have much less issue here.

Having said that, especially if you do have a more traditional mast with fore and aft lowers, inner forestays, or radar with a guard, we have grown partial to the Rozendal Trilens. This seems to be a top performer in regards to the testing conducted by the various agencies. Of course conditions, type of radar scanner, heel, and more, are all factors in how well they test. The Rozendal Trilens is a very good quality reflector and now that it has the second mounting bracket, is a sturdier option for the front of sailboat mast.

What are some other good brands out there worth checking out for sailboat mast mounted radar reflectors?

Great post! We are in the market for a radar reflector. We don’t get much fog here in the South Island of New Zealand, however we were recently sailing down the coast on an overnight trip and when the sun rose we found we were completely shrouded in fog – and had no radar or radar reflector! After posting our plight on Facebook a friend suggested we hoist a bag of screwed up tin foil up the mast, which we subsequently did. It made us feel a bit better, but not sure that it was actually effective at all! I think we will get an echo master to have on board just in case on our next coastal passage. But for our next boat – the one we sail around the world in, the Mobri does look very sleek.

Thanks Viki! We have to send you a shirt or something, you are a great follower, our best for sure. Yes on the Echomaster. And 2 Mobri’s or a Tri-lens would be my recommendatio for the more permanent solution.

Email us for a FREE shirt ! Just tell me you and your husband’s size and shipping address (American Sizes, i.e. they may be a bit BIG lol, but they’ll shrink too)

Thanks for commenting and Happy Sailing! ~T.R.C.

Yay thank you! Do you think the tin foil up the mast would work? I have had a mixed reaction from people we told as to whether they thought it would work or not. It made us feel better anyway. I will send you a message. Love your blog :)

Lol…I really don’t know but….no I don’t think so.

Ha ha – damn! Ah well at least we didn’t get run over… ;)

Just don’t fold the foil into the shape of a stealth fighter.

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• Radar reflectors

Radar Reflectors

To maximise their visibility to ships navigating using radar as a primary means of identifying potential hazards, including collision situations, boats can be fitted with a radar reflector.

In fact this is a requirement under the SOLAS V regulations:

SOLAS V 19.2.1.7 requires vessels if less than 150 gross tonnage and if practicable, [shall have] a radar reflector or other means, to enable detection by ships navigating by radar at both 9 and 3 GHz.

Essentially this means that if it is possible to use a radar reflector on your boat you should do so, but you should also be aware of the limitations of some of the radar reflectors currently available to you.

X band and S band

Marine radars operate in two bands, the X band (9410 MHz ± 30 MHz) and the S band (3050 MHz ± 30 MHz). X band radars are heavily affected by sea or rain clutter, whereas S band radar assures large target detection in adverse weather. There are now radar target enhancers (RTE) available for recreational use that operate satisfactorily in both bands.

Some passive radar reflectors also respond to both bands but with reduced performance on S Band.

ISO standards

The ISO test standards, with which radar reflectors must comply, are ISO 8729-2:2009 (Active) and ISO 8729-1:2010 (Passive).   

Passive radar reflectors built to the current standard (few, if any, are available) are often too large to be practically fitted to smaller vessels and it is with this in mind that the MCA have issued their guidance. They consider it to be feasible for vessels of 15m and over to fit radar reflectors that comply with the standard, but advise that vessels of under 15m in length should fit a radar reflector with the greatest echoing area practicable.

With this in mind, the critical factors when selecting and fitting a radar reflector remain to ensure a device with the largest possible radar cross section is carried and that it is mounted in accordance with the manufacturer’s instructions. Generally speaking, the higher a reflector is mounted, the better, although vessel operators should take account of the possible effects of the mass of the reflector on the stability of the vessel.

The current ISO test standards in very basic terms require that a radar reflector has:

• a peak Radar Cross Section (RCS) of at least 10m
• an RCS of at least 2.5m over an azimuth angle of at least 240° when the reflector is vertical (i.e. not healed over)
• an RCS of at least 0.625m over an azimuth angle of at least 240° for angles of heal up to +/-15

Radar reflector trials

Over the past few years there have been several trials carried out by the boating press, on how effectively radar reflectors for recreational boats meet these requirements. All seemingly conclude that whatever their manufacturers might claim, some designs are little better than no reflector at all and even the most popular do not always come up to expectations, this is hardly surprising when the IMO requirement is fully understood. 

Laboratory test results on passive units have shown that average RCS values are often much lower than claimed and many reflectors have large nulls (areas where there are virtually no radar returns at all). The physics of radar reflection is complicated and it is notoriously difficult to conduct trials under real conditions at sea where conditions are less than perfect and reproduce test lab results. Given that the reflection from even the best recreational reflector is also affected by positioning, orientation, and angle of heel, you may be starting to get the picture that you might not always appear on the [radar] picture!

The current ISO standards resulted from the IMO requirement set out in resolution MSC 164(78). This IMO resolution recognises that consistency of response is more effective in raising the probability of radar detection than single high peaks. This is defined as a Stated Performance Level (SPL), which is required to be maintained at up to 10 or 20 degrees (two classes recognising the stability differences of power and sailing vessels) either side of the vertical, and limits weight to 5kg and volume to 0.05 m3.

Advice from the MCA

The Maritime and Coastguard Agency (MCA) has issued a Marine Guidance Note on the carriage and use of Radar Reflectors on small vessels.  MGN 349 is a notice to all Owners, Operators, Masters and Skippers of small vessels under 150 tons including Pleasure craft. It can be read in full using the link provided, however in brief the recommendations made in section 4 are as follows:

It is strongly recommended that:

4.1 The requirements of SOLAS Chapter V Regulation 19 are complied with;

4.2 Yachtsmen permanently install not just carry on-board, a radar reflector, or RTE [radar target enhancer] that offers the largest Radar Cross Section (RCS) practicable for their vessel;

4.3 Small craft owners and operators are strongly recommended to fit the best performing radar reflector possible. It is also essential for skippers to be aware that, notwithstanding the type of radar reflector fitted, in certain circumstances their craft may still not be readily visible on ships' radars. They should navigate with caution.

4.4 The following reports published by the Marine Accident Investigation Branch are considered during the process of selecting a radar reflector: http://www.maib.gov.uk/cms_resources.cfm?file=/radar%20reflectors%20report.pdf http://www.maib.gov.uk/publications/investigation_reports/2007/ouzo.cfm

The revision of the test standards have resulted in the introduction from two UK based manufacturers of new active products (RTE’s) to the market, there were, previously a mediocre set of products to select from. The QinetiQ report on their "Performance Investigation of Marine Radar Reflectors on the Market" provides a useful insight into the effectiveness of the products they tested.

Yachting Monthly

• Digital edition

Updated guidance on fitting a radar reflector to boats under 15m

• Katy Stickland
• November 15, 2022

The Maritime and Coastguard Agency has updated its guidance and is urging all owners of boats under 15m/49.2ft to fit a radar reflector

All boats less than 15m/49.2ft and under 150 gross tonnage should permanently carry a radar reflector. according to the Maritime and Coastguard Agency. Credit: Graham Snook/Yachting Monthly

The Maritime and Coastguard Agency (MCA) has updated its guidance on the use of a radar reflector on boats less than 15m/49.2ft and under 150 gross tonnage. 

Marine Guidance Notice (MGN) 349 states that a radar reflector or radar target enhancer should be permanently installed, and offer the largest radar cross section (RCS) as practical for the vessel.

Commercial ships use radar equipment that operates in the ‘X’ band (9GHz) and the ‘S’ band (3GHz).

A radar reflector on a recreational boat should have a RCS of at least 7.5m² at X-Band and 0.5m² at S-band when mounted at a minimum height of four metres above sea level.

Just because you have a radar reflector, doesn’t mean you will be seen. Always keep a proper lookout, advises the MCA. Credit: Graham Snook/Yachting Monthly

The RCS should be maintained over a total angle of at least 280° of azimuth and not below this level over any angles greater than 10° (a null).

There should not be a distance of less than 20° between nulls.

For power driven vessels and sailing vessels designed to operate with little heel, such as a catamaran or trimaran, this performance should be maintained through angles of (athwartships) heel 10° either side of vertical.

For other vessels, the radar reflector should maintain this performance over 20° either side of vertical. Any radar reflector meeting the above requirements should comply with ISO 8729-1:2010.

If the radar reflector meeting these standards are unsuitable for boats under 15m LOA, then owners are recommended to fit a radar reflector to the older standard EN ISO 8729:1998, which has been retained for type approval under the Marine Equipment Regulations (MSN 1874) for radar reflectors for lifeboats and rescue boats.

It should be noted that Echomax has emailed Yachting Monthly to say it has contacted the MCA to express concern over their mention of ISO 8729-1:2010, as currently, there are no known passive radar reflectors which meet ISO 8729-1:2010 which has a volume limit of 0.5m3 and weight limit of 5kg.

In response, the MCA said:

‘The notice will not be amended as it can’t be confirmed 100% that there are no products of this type currently on the market, but it is highly likely during our research that this is the case.

In reference to 3.1.3 of the amended MGN:

‘3.1.3 However the above standard results in a large reflector that may be unsuitable for vessels under 15m overall length, in which case Owners and skippers of craft less than 15m overall length are recommended to consider fitting a radar reflector to the older standard EN ISO 8729:1998, which has been retained for type approval under the Marine Equipment Regulations (MSN 1874) for radar reflectors for lifeboats & rescue boats.’

EN ISO 8729:1998 remains in force until a product is placed on the market approved to ISO 8729:1.’

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The MCA is also advising skippers that in certain circumstances, their boat may still not be readily visible on ships’ radars, even when fitted with a radar reflector or a radar target enhancer, and that this does not replace the need for a proper lookout at all times.

MGN 349 was initially published following the deaths of three sailors aboard the Sailfish 25, Ouzo overnight on 20-21 August 2006.

Rupert Saunders, 36, Jason Downer, 35, and James Meaby, 36, all died when their yacht was sunk six miles south of St Catherine’s Point on the Isle of Wight after a collision with the P&O ro-ro ferry Pride of Bilbao .

Radar reflectors should be mounted at a minimum height of four metres above sea level. Credit: Graham Snook/Yachting Monthly

A report by the Marine Accident Investigation Branch ( MAIB ) found that Ouzo had not shown up on the ferry’s radars and the bridge team on Pride of Bilbao had not seen the yacht until is was very close ahead.

The officer on watch made a last minute manoeuvre to avoid Ouzo and believed he had been successful, although he did not contact the yacht crew to confirm this, and instead relied on seeing, what he thought, was the yacht’s stern light.

The MAIB concluded that the Pride of Bilbao had collided with Ouzo , or passed so close that the yacht had been swamped or capsized by the ferry’s wash. The yacht was never recovered.

The MAIB did commission a report by QinetiQ to carry out research into a number of common types of radar reflectors to compare performance with International Standards (ISO 8729).

The recommendations included:

• Using a Sea-Me radar reflector where power is available;
• Making sure the RCS of the radar reflector was a minimum of 2 m²
• Not using a 4” or 2” tube reflector due to its poor performance.

Details of MGN 349 can be found here.

Details of the full MAIB report into the sinking of Ouzo and the QinetiQ Radar Reflector report can be found here.

Please note this article was updated on 23 November 2022 after YM was contacted by Echomax about the updated MGN 349 guidance, to inform us that there are currently no known passive radar reflectors which meet ISO 8729-1 which has a limit of 0.5m3 and 5kg.

Enjoyed reading Updated guidance on fitting a radar reflector to boats under 15m?

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