Radar Deflectors

EdWingfield said:
A friend did all his research and bought the RR with the best lab test results.

At sea he called up a cruise ship (approx. 1M away) and asked O.O.W. to check his set. OOW came back and asked for more time to make adjustments. After 5 mins he said there was no target.

Unless you know they work, it is best to assume they don't.

ps. I carry a tubular reflector. I know it is useless. But RYA and possibly Colregs insist.
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Not the RYA or the Colregs

Its the SOLAS V regulations that require you to carry a radar reflector. Also to have access to anillustrated table of " life saving signals"

https://assets.publishing.service.g...e/437161/74531_Solas_V_MCA098_100714_Ver1.pdf
 
On my delivery trip from Dartmouth to Milford Haven we used the octohedral reflector as we had no other. Nothing ran us down despite thick fog in the Bristol Channel but I put this down to luck. I later fitted an Echomax and haven't been run down yet.
I agree with the previous contributor that the holes are not ideal for deploying in rain catcher orientation.
 
I have a Cyclops 1 ( The Smallest RCS version ) . On any occasion when I've needed to be seen, I've managed to contact a vessel "out of sight" on my VHF and they have located me on their Radar. On one of my particularly difficult passages from Alderney to Yarmouth, I was monitored by a container vessel and a Condor vessel until i could raise the coast guard on my VHF. Both had me on Radar the whole way. I didn't see either vessel.

I believe the Tri Lens is no longer manufactured. My Cyclops is over 10 years old. They are both based on spherical polarised lenses.

EcoMax makes the best stacked array reflectors in my opinion but I've not had one apart for fifteen years and things may have changed. They are stacked arrays of trihedral reflectors.

The standard Octohedral relflectors must be oriented in the "catch water" setting to be effective. Swinging them from a corner renders them ineffectual.

Nothing would tempt me to pay money for the tubular reflectors. They are stacked arrays of dihedral corners; in order to reflect a radar signal you need at least a trihedral pointed in the right direction.
 
As I told XXXX when he asked, published research done in QinetQ's anechoic chamber does not make encouraging reading...

https://assets.publishing.service.gov.uk/media/547c705540f0b6024400008d/Radar_reflectors_report.pdf

There are those on here who believe the orange-painted Echomax passive job is more effective in reduced visibility than the white ones.

Unless one is content to fork out ~£760 ( Amazon ) for an Echomax Dual Frequency Transponder, the best passive radar target enhancer is a string of 6 of those foil bags which line the insides of wine boxes, inflated, and halyard- hoisted above the spreaders. Cheap as chips!
 
zoidberg said:
Unless one is content to fork out ~£760 ( Amazon ) for an Echomax Dual Frequency Transponder, the best passive radar target enhancer is a string of 6 of those foil bags which line the insides of wine boxes, inflated, and halyard- hoisted above the spreaders.
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Really? What is your evidence for that?
 
Be interesting to know of any cases of a yacht using an Echomax passive reflector being run down by a ship. I use an Echomax because their advertising says that their used by the RNLI.
 
Pkewish said:
Hi,

Having recently found myself sailing in fog without a deflector, I was wondering which type performed the best. My 2 options are:

Tubular back stay mount
Or
Octrohedral mount on a halyard.

Both are similarly priced so your thoughts please.

Pete
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Having been involved with tests on passive reflectors, none had any noticeable effect on a radar target at all. In the absence of an active reflector, the best target is made by the hole your boat makes in the water, in choppy conditions that would easily be lost.

The fact is that an active reflector is best, and one which works on both the X and Y bands. AIS is OK, but the two key issues are whether the opposing boat is monitoring AIS and taking into consideration the delay in your transmission and therefore your correct position.

All of this points to radar being the best option to see in fog, and for the target vessel to be using an active X and Y reflector.
 
Piers said:
Having been involved with tests on passive reflectors, none had any noticeable effect on a radar target at all. In the absence of an active reflector, the best target is made by the hole your boat makes in the water, in choppy conditions that would easily be lost......
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Can you document that?
Because like many people in the radar industry, I've found corner reflectors pretty effective.
That's why there's millions of them about on buoys, channel marker piles etc where they've performed adequately for the last 2/3 of a century.

The idea that your boat makes a hole in the water which functions as a good reflector tends to break down as soon as the wave height is comparable to the draft of the main body of the hull. For a modern AWB that means it might work on Southsea Canoe Lake, but best not venture out of the Camber Dock, let alone into the Solent.

There is some merit in the idea that it's a lot easier for a radar on a little plastic yacht to see a big metal ship than v/v. These days the price of an active reflector goes quite a way towards buying a radar, particularly as an upgrade to a plotter.
 
lw395 said:
Can you document that?
Because like many people in the radar industry, I've found corner reflectors pretty effective.
That's why there's millions of them about on buoys, channel marker piles etc where they've performed adequately for the last 2/3 of a century.

The idea that your boat makes a hole in the water which functions as a good reflector tends to break down as soon as the wave height is comparable to the draft of the main body of the hull. For a modern AWB that means it might work on Southsea Canoe Lake, but best not venture out of the Camber Dock, let alone into the Solent.

There is some merit in the idea that it's a lot easier for a radar on a little plastic yacht to see a big metal ship than v/v. These days the price of an active reflector goes quite a way towards buying a radar, particularly as an upgrade to a plotter.
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Hi lw395. Of all the passive reflectors, the only one that appeared to have any potential influence on a target was the octahedral in the 'catch rain' position.

The late and great Robert Avis (http://www.mby.com/news/robert-avis-mby-writer-dies-14220) wrote many articles on radar, not the least being the key difference between sea-stabilised and ground stabilised radar, the essence of this having come to the fore after the collision of the Yacht Wahkuna and the Netlloyd Vespucci.

Robert would emphasise that the engine and mast of a yacht would reflect far less than its hole in the water. But, given sea clutter as the sea becomes more emotional, even that would be lost. Hence, the old method of water on the sails would be better.

Robert's best advice was to see and be seen, the latter being by active reflector on both frequencies.
 
Piers said:
Hi lw395. Of all the passive reflectors, the only one that appeared to have any potential influence on a target was the octahedral in the 'catch rain' position.

....
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For clarity, 'corner reflector' and 'octohedral' are often the same thing, the octo being 8 corners if you see what I mean.
I think there are several passive reflectors which are on the whole at least as good as the classic octo.

The Wakhuna case is a classic lesson that two vessels seeing each other is only one ingredient of not colliding.
A good book or two and a training course can be better investments than gadgets.
 
Of note, in the case of an octahedral reflector, only six of the eight "corners" are close to effective when considering other ships. One points directly above the vessel and one towards the deck. If you read the QinetiQ report you will also see the polar diagrams of the reflectors tested. These are a measure of the directional power reflected. There is a noticeable spike reflected by a corner which tails off quite quickly as the orientation of the corner changes from optimal.

The tri-lens reflector gives a consistent echo, whatever the orientation ( the cyclops reflector was not tested as part of that report.

Passive reflectors such as those considered in the report have a zero power burden. For an active reflector to be of any use, you either need to be under engine or have a well charged battery bank.
 
Topcat47 said:
Passive reflectors such as those considered in the report have a zero power burden. For an active reflector to be of any use, you either need to be under engine or have a well charged battery bank.
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The Echomax gives a maximum consumption of 190 mA when transmitting, which is hardly onerous.
 
johnalison said:
The Echomax gives a maximum consumption of 190 mA when transmitting, which is hardly onerous.
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In receive mode, it will still consume power. When at sea it will respond to each incident radar emission from every radar equipped vessel in range. This is in addition to other burdens, like log. depth, GPS/plotter, etc... Whether this is a problem or not will largely depend on the size of your domestic battery bank and other demands.

I have a small boat, with standard ( but period )instrumentation, an old PC as a plotter, and Nav lights which is quite a load for my 85aH battery to supply. On a typical Solent - Cherbourg trip, I will usually need to top up the service battery at least once, three times for an overnight passage. All this without a transponder. Anything with a Zero Power burden and proven effectiveness ( which I consider my Cyclops has adequately demonstrated for my peace of mind ) is better than something that adds to my electrical needs.
 
Topcat47 said:
In receive mode, it will still consume power. When at sea it will respond to each incident radar emission from every radar equipped vessel in range. This is in addition to other burdens, like log. depth, GPS/plotter, etc... Whether this is a problem or not will largely depend on the size of your domestic battery bank and other demands.

I have a small boat, with standard ( but period )instrumentation, an old PC as a plotter, and Nav lights which is quite a load for my 85aH battery to supply. On a typical Solent - Cherbourg trip, I will usually need to top up the service battery at least once, three times for an overnight passage. All this without a transponder. Anything with a Zero Power burden and proven effectiveness ( which I consider my Cyclops has adequately demonstrated for my peace of mind ) is better than something that adds to my electrical needs.
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I'd think the 'old pc' used very much more than a radar transponder.
190mA is 4.6 Ah per 24 hours.

I have sailed crisers where that would have been an issue, but it was a very long time ago!

But if you have one of the better passive reflectors, if a ship does not see you, it's most likely because they are not looking at their radar.
 
lw395 said:
But if you have one of the better passive reflectors, if a ship does not see you, it's most likely because they are not looking at their radar.
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I really don't bother anyone if the viz is good, my Alderney return involved fog and F6 wind. I didn't ever catch sight of either of the good samaritans who saw me home. Nor did they see me. I am just so grateful for the watchkeepers on both vessels who not only kept me "safe" but reassured me that I was also in the clear regarding other vessels.
 
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