Radar reflectors

[panthablue]

I am interested in peoples opinion.

Which type of radar reflector do people think is the most effective, and which type of radar reflector do people prefer to buy?

[Auzzee]

Hi Panthablue, Over the years I have seen many comparative tests for radar reflectors in a variety of magazines. It seems to me that in practical terms the difference between the very expensive tri lens reflectors and the basic octahedral type is not the strength of the reflected image but the consistency. On a flat sea there would be very little difference in their respective performances. In big seas the performance of both types probably varies from bloody useless to moderate. If you have the dollars available, I suggest you look at Collision Avoidance Radar Detection (C.A.R.D.) This alerts you of the presence, bearing and distance of other radars and along with a cheap octahedral reflector, a good watch keeping regime and your own radar in conditions of poor visibility (to spot the boats without radar) you should be able to remain safe from clouting other boats. Best wishes. David

[Baggywrinkle]

Yachting Monthly June 2005 did a 10 radar reflector test

[pelorus32]

I can attest to how useless the passive reflectors are in anything but calm conditions. We had a recent experience in Bass Strait where despite a radar reflector up our mast (Davis Style) we were completely invisible to ships as close as 300 feet away. To quote one OOW "you don't paint mate".

There is also a war of words between the various sales people about which reflector works and which doesn't.

My bottom line is that if you really want to paint on radar screens go with one of the active systems that respond to a radar pulse by sending a return signal. Difficulty is that ships use two distinct bands for their radar (3 and 10cm IIRC) and the active systems only operate on one (3cm IIRC).

Alternative option is to look into a SART which is a user triggered active system.

Regards

Mike

[Swagman]

We completed a trip in company with 25 other yachts this summer and I was surprised to see (we have a MARPA set up on our own radar) most of our companions were not clearly visible on radar bayond a range of approx 5 miles. THey used a variety of reflectors - and all seemed equally poor.

The only ones recently rated as exceptional in a recent UK sailing magazine test were the electronic 'Sea-Me' responders - and were I to be doing any extensive sailing in fog (and I'm not) - then I'd fit one of those.

Cheers

JOHN

[Jack Tyler]

We had an eye-opening experience not too long ago: departing Tortola enroute St. Martin one late afternoon, there was a large fleet of boats who'd been waiting for the Trades to settle down - from 90'/30M+ motoryachts to small cruising sailboats. We had a 360 degree view of this fleet and a fair idea of this gaggle's size and distribution when the sun disappeared and the nav lights started coming on. We turned on the radar and the only boats that registered on our unit were the small ones! None of those sleek, over-swollen motoryachts had a signature; none of them showed a mounted reflector nor were operating a transponder, either. Amazing...

The YM article mentioned above is excellent. As I read it, it also paints a totally different picture than Pelorous & John offer us of the relative performance of different passive reflector models. I don't know why Pelorous' passive model didn't work, but we find a similar model to be quite effective (we query ships & yachts routinely for a radar report) and there are other models which perform well (and still others that are worthless). Perhaps this is because his passage in Bass Straits was during active sea conditions, as big ship radars (on S band, as I recall; X band is used in port maneuvers) operate exclusively in a detection-percentage mode. This means if the radar doesn't see your blip more than X% of the time, it assumes your blip is wave action. This is why Auzzee makes the observation he does re: consistency. It's also a reason why mounting the reflector higher is better than lower; e.g. reflectors mounted on aft radar arches strike me as unseamanlike, even if 'easy'. The YM article demonstrates major differences in passive reflector performance, and the same conclusions were drawn by Belvoir Pubs in tests they've done for their magazines, including Practical Sailor.

See-Me type 'transponders' are clearly much more effective. OTOH I see many owners can't even manage to buy a good passive unit and mount it properly, so expecting everyone to pony up big bucks for another electronic gizmo is not going to suit everyone. And presuming a good watch, VHF in the cockpit and skilled use of a working radar, it is w-a-y down my list of desired improvements. In addition, I would much prefer to install passive an AIS unit sooner than a transponder, anyway - it gives me a good deal to work with including ship's name, track & intercept data, etc., certainly beyond what can expect form a radar. This makes VHF contact more feasible in these GMDSS days, is more suitable in conjested areas like the sea lanes off Miami or the English Channel, and it helps me to be more proactive vs. passive.

Just some food for thought...

Jack

[Swagman]

Sorry if my comprehension of the YM test was not the same as Jacks - but I stand by my recollection that it rated only the 'Sea-Me' type device as exceptional - with all the rest pretty dissappointing - and some downright useless.

I guess others who have an interest can search out that test and then perhaps decide themselves.

Cheers

JOHN

[Nausikaa]

Having stood on many a bridge as officer of the watch on ships of varying sizes I can honestly say that radar reflectors are not as good as they should be....but far better than no radar reflector at all.

Radar is a funny beast. Before the advent of ARPA units I was OOW on a ship outward bound from Hamburg for Cape Town. We dropped the pilot at the Elbe 1 light ship and proceeded down the sw-going trafic lane and after a while I found I had an echo very slightly on the starboard bow. We were in a real pea-souper of a fog and so I plotted (remember chinagraph pencils?) and found the echo to be moving slowely AGAINST the trafic flow. When we got closer, there had been no change in bearing so I stopped the ship and thereafter proceeded at a snails pace. When we saw the object I had so carefully plotted it turned out to be a seagul standing on a wooden palet being swept towards the mouth of the Elbe with the rising tide. Amazing! I stopped a 14,000 ton ship for a seagul but I most certainly got clear evidence that the radar was working well. (but it was very calm weather too)

On the other hand, on a much later occasion I was OOW on a 10,000 tonner heading southwards a good way off the coast of Portugal in a force 6. Visibilty was good and I had just taken a noon sight and was working out our latitude when I caught sight of a small fishing boat not far away, maybe half a mile off. The boat was white and was 'lost' in the sea of white wavecrests. Not only was it hardly visible to the eye but it showed no echo on the radar either. Of course, I must admit that there was some radar clutter in caused by the choppy sea but the important thing is that the boat could hardly be seen.

Clearly, if you want to be seen at sea don't paint your boat white and do everything possible to increase your radar 'paint'. Get a radar reflector and mount it as high as possible! According to current regulations these are compulsary items anway. If you have a limited budget (and who doesn't) I would not go for the Sea-Me which is a pricy piece of kit but would have a little patience and buy an AIS transponder wher the small craft version comes out. This will let you be seen by the big guys but will also enable you to see them.

I too read the YM article and was unimpressed by much of the kit they had tested - and shocked at some of the prices. I will not be buying an expensive reflector or Sea-Me unit for my boat but will continue with the old fashioned, conventional (and cheap) reflector I have, mounted at the mast head and will definately be in the marked for an AIS transponder next season.

Cheers,

Stephen,

Yacht Nausikaa

[Jack Tyler]

To Stephen's point, the YM article (which some found worthless but I found discriminating) points out that only the Echomax EM230 meets current ISO 8729 and SOLAS specs. It's performance is to be sure only a fraction of the See-Me (powered, expensive, transponder-type) unit YM tested, yet it's performance exceeded all the competition.

The critical points would seem to be:

1. active transponder if you can afford it

2. picking a more effective passive device beats picking a less effective one

3. an effective passive device is better than no device

4. when making the above choices, weigh them alongside the value of AIS for your sailing waters

Jack

[Nausikaa]

Thanks for your wise comments Jack.

I agree that one should examine all options and, if money is no problem, the options may be to double up on systems. There is nothing wrong with having both a radar reflector (of any type) and a Sea-Me unit as well. In fact, if you can afford it, why not go the whole way and get an AIS unit too?

Cheers // Stephen

[Auzzee]

The September issue (#148) of Ocean Navigator (OceanNavigator.com) has an article by Tim Queeny on AIS: Collision Avoidance Without Radar. It contains some interesting data regarding AIS units.