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Old 03 May 2007, 14:29   #21
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thanks v much
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Old 08 May 2007, 15:40   #22
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I would hope that the manufacturers of these things figured this all out and so if we mount these things "properly" (i.e. vertically, which is the only I can mount mine, then that would be fine...)

As I mentioned in my post, having been "pinged" by friends, there is no doubt that these things work. Considering the low cost, it seems that these should be standard gear on a RIB...
I am not sure the MAIB/QinetiQ would agree with you...

Here is the additional report they promised they would release following the Ouzo accident:

http://www.maib.gov.uk/cms_resources...s%20report.pdf

Nothing in here came as a great surprise to me based on what I have heard here, and read in magazine reviews.
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Old 08 May 2007, 15:52   #23
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And to illustrate the fact that opinions are so subjective the Sea Me comes out head and shoulders above the rest. Wonder what it is thats causing the problems with Scorpion? I will investigate further this weekend.

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Old 08 May 2007, 16:30   #24
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Interesting. To some extent it's what you'd expect of them by just imagining the path of reflection of the radar wave.

It highlights other tests which concluded the tube type were feck all use and, if mounted horizontally, would only be seen absolutely square on to the bow or stern. That's not a likely situation for any worthwhile period of time on water.

It occured to me a while back that the best angle peaks and the worst angle troughs recorded in all the tests I've seen of passive reflectors, could possibly be averaged to some extent if the reflective surface was planished or dimpled to some extent.
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Old 08 May 2007, 16:39   #25
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And to illustrate the fact that opinions are so subjective the Sea Me comes out head and shoulders above the rest. Wonder what it is thats causing the problems with Scorpion? I will investigate further this weekend.

Ollie
Ollie, the one thing against the Sea-Me on a RIB is the lack of water proofing of the small control box. However, it's only a small plastic box and replacing the innards into a watertight box or placing the whole thing into a watertight container would not be difficult. The only facility you need in normal use is to switch it on and off so it could be easily done in a few ways. It also has an LED which alerts you if it's transmitting a radar signal; which implies it is receiving a radar signal. It could possibly be useful but, again, it's not rocket science to mount an LED remotely.
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Old 08 May 2007, 16:44   #26
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I don't know why the trl lens doesn't become the standard for powerboats as it's so easy to mount. Even the makers seem to have missed the point - they keep showing them attached to masts and they just don't fit right - they are perfect for an A frame or Radar arch - much less windage than the dustbin style!!!
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Old 08 May 2007, 16:47   #27
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It occured to me a while back that the best angle peaks and the worst angle troughs recorded in all the tests I've seen of passive reflectors, could possibly be averaged to some extent if the reflective surface was planished or dimpled to some extent.
I'm not sure that would work (I'm not an expert though). If I remember correctly the wavelength of "normal" marine radar is a few cm. Therefore any feature/texture less than that (or perhaps 1/2 the wavelength) is unlikely to be reflect the light as you would expect. There might be strange scattering or even polarisation effects?
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Old 08 May 2007, 16:50   #28
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I don't know why the trl lens doesn't become the standard for powerboats as it's so easy to mount. Even the makers seem to have missed the point - they keep showing them attached to masts and they just don't fit right - they are perfect for an A frame or Radar arch - much less windage than the dustbin style!!!
I suspect cost is a factor.

They are also not small which means large powerboat - large powerboat more likely to have its own RADAR (and as power not an issue it will be turned on) - so can take a defensive stance rather than hoping the ship sees you.
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Old 08 May 2007, 16:53   #29
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I'm not sure that would work (I'm not an expert though). If I remember correctly the wavelength of "normal" marine radar is a few cm. Therefore any feature/texture less than that (or perhaps 1/2 the wavelength) is unlikely to be reflect the light as you would expect. There might be strange scattering or even polarisation effects?
Why would the indentations being less than a wavelength be significant? My understanding is that polarisation by reflection only takes place on non-metallic surfaces.
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Old 08 May 2007, 16:53   #30
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interesting report that from qinetiq..the funtington site is 1/3 mile from my house, didnt realise it was still functioning, always looks deserted...anyway, based on report, I think it'll be the Seame then...
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