Bug-eyes on my masthead

[tjfmmaes]

This is probably a terribly stupid question, but here goes anyway: having recently bought a secondhand Oceanis 350 I only last weekend noticed something strange on my masthead. Closer inspection with binoculars revealed an offwhite contraption sitting underneath the anchor and trilight. It is shaped like a pill capsule, probably 30-35cm long (ish) , and is pinched in the middle where 2 coneshapes meet each other. I had a look at other boats in the marina and some of them have the same thing, so it must have a function...

but what is it? any answers as usual gratefully received. (and yes I don't mind being told off for being completely batty and should know what's on the top of my boat.....)

Thanks

Tom


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[LORDNELSON]

Radar reflector?

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[tjfmmaes]

Thought about that, but a) it doesn't look big enough and b) the cones face fore a nd aft and therefore that would miss out about half the boats radius.

Also, one of the other boats that had it, had a radar reflector as well.

But perhaps....

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[steve6367]

TV Ariel would be my first guess............

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[steve_cronin]

Yes....

Radar reflectors of that design were sold to the gullible in the 70s & 80s. Yacht mag tests showed them no more effective than the bare mast.

It was called a "Visi-ball" and the "stated" principle was like that of two of the original radio telescopes back to back.

Steve Cronin



<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[Bejasus]

See it <A target="_blank" HREF=http://www.seamarknunn.co.uk/catalog/items/item1429.htm>here</A>.

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[Oldhand]

These radar reflectors were a sideline of research work done at what was ASWE (now DERA I suspect) up on Portsdown Hill behind Portsmouth. The main advantage was the ability to masthead mount rather than out & out performance.

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[Talbot]

The technology (Luneburg Lens) works very well in specific applications, and might have had a place on a multihull or mobo, but the heel experienced by an average raggie meant that the lenses were never really able to line up correctly, and were also too small. Get rid of them, they serve no useful purpose other than being able to state that you have a radar reflector fitted for solas (AFAIK Solas does not actually mandate a perfomance requirement, only that a reflector should be available)

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[isandell]

ASWE, then DRA, then DERA, now privatised as QinetiQ.

Ian

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[TrueBlue]

Bother - all this sensible information; I was going to suggest a pair of Tannoy Public Address speakers mounted for instructing Crew, or saying nasty things to mobos..., Especially in view of other raggie / mobo discussions on this site.

HoHum, Truth will out.

<hr width=100% size=1>Stop what you're doing and wait my signal

 

[extravert]

The RYA have translated the SOLAS requirements into plain English for us here...

<A target="_blank" HREF=http://www.rya.org.uk/Cruising/solas/>http://www.rya.org.uk/Cruising/solas/</A>

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.

 

[tjfmmaes]

Thanks for all the answers. I guess I don't have to swat that bug of my mast after all. I am also glad that the reputation of the Visiball (and test results I found) is so poor as otherwise I would have had to justify my recent purchase of a decent radar reflector (I hope) to my wife. As bugeyes might do some good, I'll leave it where it is, unless it causes intereference with my new reflector (a mobri, the biggest one). Is this the right course of action then?

Thanks once again for all replies.

Tom

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