Radar reflectors and you.... - SailNet Community
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post #1 of 36 Old 12-23-2007 Thread Starter
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Radar reflectors and you....

After reading the coments on -Sailing in the fog- and recomendations for radar reflectors, I found a report called “Performance Investigation of Marine Radar Reflectors on the Market, ” along with a report on the tragic sinking that prompted it.

http://www.ybw.com/pbo/pdfs/radar_reflectors.pdf

Three sailors died after the big ferry Pride of Balboa apparently ran down the 26' yacht Ouzo early one morning near the Isle of Wight.

The testers concluded that only the Sea-Me active reflector delivers a strong enough radar return to even meet the ISO 8729 standard, and some perform so poorly that they aren't worth carrying because they'll only give you a false sense of security.

I guess we remain specks in the ocean ... it sucks to be the little fish.

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post #2 of 36 Old 12-23-2007
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Class A and B ais( automated identity system) plotters or transponders may the way of the future. Commerial vessels will be required to have them( class a) or may already be required. There has been some hype about class b for smaller vessels and sailboats, but again may lead to some false securty. Also Class B recievers make 2 sweeps per minute. Class A broadcasts every 2 seconds but some ships may even filter out class B signals, or nobody may even be watching it. Radar I think has 24 sweeps per min which is way less than what the class A transmits.
I am sure there are some on this board who may know more on this.
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post #3 of 36 Old 12-23-2007
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I use one of the Davis aluminum ones all the time. They supposedly do make sailboats at least slightly more visible. If nothing else, I figure my wife can sue Davvis after I am run down by a big ship.

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post #4 of 36 Old 12-23-2007
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To me a passive radar reflector is one of those things that are sold because there is a need, even if they don't work ... because they seem like they might work. I don't remember reading a single scientific study that says that they actually DO work.

What are you pretending not to know ?

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post #5 of 36 Old 12-23-2007
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This is a pretty definitive study on passive reflectors. For those with short attention spans....the Davis Echomaster "won"...but the detail is worth understanding to get best results from it.
http://www.ussailing.org/safety/Stud...test.htm#INDEX
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post #6 of 36 Old 12-23-2007
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I've got a Tri-Lens Reflector that seems to work pretty well. It was rated #1 by Practicle Sailor.

http://www.tri-lens.com/trilensweb12002001.htm
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post #7 of 36 Old 12-24-2007
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Practical Boat Owner (UK) has a sea-trial of AIS in January 2008's issue. Automated Indentification System, AIS, technology should become quite affordable and accessible in the near future for all sizes of vessels. Affordable to the extent that yachts should find it no hindrance to carry at least the transponder if not a receiver. Given the relative speed differences between yachts and ships, it remains more important that the ship see the yacht as she will, in most cases offshore, be more able to void collision.

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post #8 of 36 Old 12-24-2007
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The only problem with AIS is that it requires electricity to work.... and electrical systems on small boats are not the most reliable in the world. That is also the problem with the Sea-me active radar reflector.

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post #9 of 36 Old 12-24-2007
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Quote:
Originally Posted by sailingdog View Post
The only problem with AIS is that it requires electricity to work.... and electrical systems on small boats are not the most reliable in the world. That is also the problem with the Sea-me active radar reflector.
Unfortunately, that is not the only problem with AIS. Another big problem is that bridge crews do not always pay a lot of attention to it -- generally less than they do to radar. The early versions had a stand alone display screen that, while required to be installed on the bridge, often was tucked away in a closet somewhere. Many harbor pilots reported coming aboard ships and finding that the bridge crew on duty didn't even know where the AIS display screen was located, especially with foreign crews/flagged ships (it's a USCG-originated requirement, afterall.)

Newer AIS can interface with the ECDIS, which helps to get the info in front of bridge crew. But the information being displayed is confusing often enough that bridge crew tend to be skeptical of what they're reading. Examples of confusing information occur, for instance, when bridge crew neglect to update the ship's status line, so their AIS transceiver may be broadcasting that they are "quayside - Seattle" when they are actually steaming out of the Straight of Juan De Fuca.

As currently configured, AIS seems to be a greater benefit to HomeLand Security entitites, and business enterprises that track cargo shipments (e.g. http://www.aislive.com/ ), than it is to commercial vessels or recreational sailors. But that will likely change as potential benefits of AIS are exploited by technology upgrades.

Here I must add a disclaimer as my company is involved in devellopping technology that aims to exploit the AIS network to greater advantage.
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post #10 of 36 Old 12-24-2007
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Quote:
Originally Posted by camaraderie View Post
This is a pretty definitive study on passive reflectors. For those with short attention spans....the Davis Echomaster "won"...but the detail is worth understanding to get best results from it.
http://www.ussailing.org/safety/Stud...test.htm#INDEX
The study is dated 1995, and it unfortunately does not include testing of the only type of passive radar reflector that IMHO works: the Luneberg tri-lens. As mentioned above in post #7 by Slipkiller2, Practical Sailor recently found that it gave the best results of all they tested.

I've used a tri-lens on my last three boats. I'm told my current large-size Rozendal makes me paint like a large ship.

Cheers,
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