Radar reflectors

[c_j]

I see that the latest ? rules from MCA regarding vessels over 45ft require amongst other things a radar reflector. I cannot see one in our Marina on a power boat but anyone any ideas on this or has any one actually got one?

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cjs@stone.uk.com


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[Geoffs]

Don't know much about 'em,but was reading about active radar reflectors the other day. They require power, receive and incoming signal, amplify it and re-transmit. Quite small units, but equivalent to a target of many square metres. seems a good idea, but if they work, I know not.

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[byron]

Most reflectors are rubbish and the rule was probably brought in by some Pratt who took up boating this year, read a book and is now an expert. You can comply with the law by purchasing one for about £12.
In my experience the best signal you can get is from your rails and lumps in the engine room. With sailing craft a set of wet sails gives one hell of a signal. But! Hey! what do I know? I ain't read the book.

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[c_j]

Thanks for that. I had almost decided to purchase said £12 one so as to satisfy the law but was interested to see how others were.




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cjs@stone.uk.com


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[BrendanS]

loads of posts on this subject over last 18 months. If under 15metres some leeway as MCGA interpretation is that fitted where practicable. Their interpretation of rules is that where practicable applies under 15m, and that over 15 meters it is practicable to fit a radar reflector of 10m2 (with lots of caveats)

When was your boat built, as there is a cut off date that is not well publicised.

Agree with Byron that the things don't work, but legally you might be hard pushed unless someone challenges first in case of accident.

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[rich]

I can pickup seagulls on my radar, do they have reflectors?

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[MapisM]

Crazy rules

Gosh, that is a funny rule indeed.
It would make more sense to require the radar reflector for boats SMALLER than 45ft, rather than bigger !!!
I wonder which book they read to invent such rule, "boating in the himalaya" maybe?
Here in Italy the reflector is required when sailing at more than 12 miles from the coast, regardless of the boat's length.
Also a crazy rule imho, but not as much as the MCA one !
Would be interesting to make a contest for the most crazy rules around...
What about requiring to have onboard a watch (yes, any normal watch), unless staying within 12 miles from the coast?

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[qsiv]

I have found that it's actually quite difficult to get a 'yacht' sized reflector that meets the specification. I don't believe any of the canister types get close, and it's only when you get up to about 24" or 30" that the standard tetrahedrals comply. As for finding somewhere to PUT such a big reflector, where it doesn't get in the way, or cause damage ... .. .

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[Observer]

I have been researching radar reflectors to make an informed choice for our new boat. Without going into too much detail, I narrowed down the choice to four:

Tri-lens (standard size)
Dia. 300mm x H 150mm Weight 2.5kg. Price £130 ish (West Marine price although I understand is available from Viking). It is approx. size of a radome except it's a sort of clover leaf array of three spheres. Would look OK on a mobo and a yacht. Max. performance is 2-4 sq.m RCS (which I think is equivalent cross-sectional area)

Firdell blipper 210-7
H 595mm x dia. 240mm Weight 1.8Kg. Price £130 ish (available widely). Being cylindrical, it's more suited to a yacht than a mobo. Max performance is 8 sq.m RCS.

Echomax EM230+
H 610mm x dia. 248mm. Weight 2.1kg. Price £130ish. Cylindrical like the Blipper but the max. performance is 24 sq.m RCS and it meets the 10 sq.m ISO8729 standard 70% of the time.

Firdell Blipper P-175
Dia. 595mm x H 225mm. Weight 6.7kg. Price £230ish. Also a radome type affair but considerably larger, heavier and more expensive than the Tri-lens. I haven't seen any published performace data for it but Firdell claim in conversation performance close to that of the 210-7.

Firdell also stated that the performace claims for Echomax are maximum not mean returns, which may well be correct. However, as Echomax's maxima are much better than Firdell's, is it likely that the mean will be better as well? Not sure but I think if I had a yacht I'd go for the Echomax. On a Mobo, the issue is whether it can be mounted in a way which is aesthetically acceptable. The Tri-lens is probably the best for that purpose.

If you want to see this for yourself, searches on "Tri-lens", "Firdell Blipper" "Blipper P-175" and "Echomax" will throw up plenty of material.



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[duncan]

Re: won\'t they work in a locker?

OK this is probably a stupid question; but it won't be my last...........
Do you need to have the thing anywhere out in the open? and if so why?
(in this I accept that higher is generally better) Will it work as well in a locker?

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[AndrewJ]

Re: won\'t they work in a locker?

If the locker is up as high as you can get it. The idea of the radar reflector is to reflect radar beams, which are mostly line of sight, at the earliest possible point if you're being approached by a vessel by radar. If the reflector is in a locker, it's probably near sea level, hence the
approaching vessel would have to be almost on top of you to hit the reflector. (think of an object on the shore, the higher you are, and/or the
higher object on shore is, the farther off you'll be able to see it..) At least that's my understanding. There is a formula for visible horizon, which I forget, that would apply closely for a radar horizon.

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[Observer]

Re: won\'t they work in a locker?

Question answered already I think. You need to mount it as high as possible which on a mobo means on the radar arch.

I should have mentioned that I considered but dismissed the Sea-me (this is an active radar target enhancer rather than merely a reflector) which is neat and small but quite pricey at £450ish. For the sort of use we get from a boat, it would be a step too far, I think.



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[Dave_Snelson]

Re: Crazy rules

How about...

"You must carry a mobile phone with you when you intend to cruise more than 12 miles offshore"

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[Wiggo]

we put one on a couple of years back, as it appeared to be a requirement for cruising with the F'line Owners Club. As much use as tits on a chicken, as far as I can make out. The top half snapped off earlier this year, but I glued a new lid on. From looking at other boats at sea, and checking their radar signature, they all seem as bad as each other. There was an article in MBY about the dangers of using the active ones: apparently some bloke got followed into his marina by a 100,000 ton bulk carrier in the fog, cos it got such a huge reflection from him they thought he was the same size as them, and heading up the channel.

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[BrendanS]

Hve yo seen this site....detailed comparative tests of many different types of reflector

<A target="_blank" HREF=http://www.ussailing.org/safety/Studies/radar_reflector_test.htm#INDEX>http://www.ussailing.org/safety/Studies/radar_reflector_test.htm#INDEX</A>

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[Observer]

Yes. I looked at this site but the test was 1995 so now somewhat out of date. I think there has been updated test on the Firdell Blipper following complaint by the manufacturer about the test but the result of the second test wasn't much more impressive. As far as I can tell, it's all a matter of size rather than what you do with it. No substitute for a big'un.

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