Bil Hansen wrote:
"Jeff Morris" wrote ...

....

So, you're saying that you use and recommend a radar reflector that in
you experience doesn't actually work? Yea, that makes sense.


I must have erred in my writing! Or perhaps you misread me?

I don't recommend any radar reflector. I pointed out that (1) West Marine
has given Mobri bad press but (2) the USCG has seen fit to specify Mobri
reflectors as internal reflectors in some of its buoys (and I assume that
the USCG did tests of reflectors). I think the USCG specification is
curious. And tried to say as much.


I apologize - I inferred from your comments about the USCG, and the
fact that you have a Mobri, that you felt the bad press was
unjustified. I should not have presumed that.

My take on the CG requirement is that they wanted something that would
fit in a cylinder built into small inland buoys that are constructed of
rolled foam and have very little metal. At the time, 1995, Mobri may
have been the only candidate. There are other companies that make this
style of reflector now so I can't say if Mobris are in use. At any
rate, these are not buoys that ships use to find harbor entrances in a
storm, they are used to find the next bend in the ICW.



If you read me as recommending any reflector by brand name, let me be clear
that I do not: I instead recommend that a skipper keep a good watch and not
rely on having a radar reflector.

Relying on a reflector is silly - it requires that someone else actually
is watching. However, if you're going to carry one on the top of your
mast all the time, doesn't it make sense to use one that actually reflects?


My experience is that, in a seaway, cargo ships that I've called on VHF have
had trouble locating me (with a Mobri reflector) by radar. But the USCG and
the USN has never had a problem locating and, when it served them,
interdicting me. My experience is that at 3 nm most all sailboats, including
those with bigger reflectors than mine, show on radar as tiny dots (in
contrast to the Big Dot promised by the reflector that seems never to have
gone into production) that fluctuate in reflectance, because of heel etc.

I'd be curious to see what the are. I'm guessing that the "12" model is
12 inches in diameter, making it rather large for masthead use. And it
would be fair to compare to the large commercial Blipper (300-5) rather
than the smaller version. Still, an active unit would be even better.



I have no dispute with you about the external reflectors on buoys: but
they're bigger and more solid than a Davis Echomaster.

Actually, the 6NFR and 6CFR buoys from the spec you referenced use,
instead of the cylinder style, a Davis style square corner aluminum
reflector that's smaller than the folding units many boats (myself
included) carry as a spare.



So what about you and your ocean experience: I'm guessing that you have done
more than three circumnavigations?

Only in my dreams. However, I've been cruising the New England coast
for about 25 years. Much of the Maine coast has fog on a daily basis
all summer - I don't see the sense of carrying a reflector that
disappears when you heel 20 degrees.

How about a C.A.R.D. detector? http://www.survivalsafety.com/

Gordon

"Keith" wrote in message
...
Here's a test from 1995:
http://www.ussailing.org/safety/Stud...ector_test.htm


Here are some interesting types:
http://www.rozendalassociates.com/reflectors/

Then finally, how about an active reflector, instead of passive?
http://www.sea-me.co.uk/

--


Keith
__
Leaving the dock is optional. Returning is mandatory.
"Gordon" wrote in message
...
What works? What doesn't? What to buy?
Thanks
Gordon

I've never used one of these, but the idea is interesting:

http://www.speedseal.com/seame/welcome.htm

.... it apparently works along the same lines as a SART, enhancing your
radar "blip" by using an active transponder.

Two other points I'd add:

We used the "el cheapo" Davis reflectors on drift buoys on the research
ships I've been on. With the reflector, the buoys were usually visible
on radar at 10-12 nm out, without the reflector they were almost
entirely invisible to the radar no matter how close we were. Not very
scientific, but pretty good evidence that they work IMHO.

No matter how "good" your radar reflector, it by no means replaces your
need to stand an alert and vigilent watch.

--

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Renewontime
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My take on the CG requirement . . .

NavAid bouys suffer from bird splat and damage problems, so for a small
device the enclosed feature of the Mobri makes sense. The big'uns have
retroreflection built right in to the structure, or an actual racon.

My take on the issue is unless you have a large (or sluglike) boat that
doesn't mind the windage of an effective (read expensive) permanent
mount reflector, a Davis EchoMaster raised high on a burgee halyard in
the catch rain position is reasonable. It's light weight, unaffected
by heel and moves around enough to mask null return problems. Fix a
few strands of yarn on a corner so it doesn't spin like a banshee in
high winds and snarl its halyard.

On Mon, 21 Feb 2005 08:06:54 -1000, renewontime dot com
wrote:

We used the "el cheapo" Davis reflectors on drift buoys on the research
ships I've been on.

===================================

Offshore commercial fishing boats also use them to mark their buoys
which is a pretty good recommendation. I have carried a small folding
Davis for years which I assemble and display in foggy conditions,
usually elevated on the end of a boat hook. I've been told that it
shows up well. On the other hand my new 4KW Furuno radar has no
problem picking up small boats of all types at 2 to 4 miles, at least
in flat water conditions.