RADAR reflectors

Valkyrie · Posted: Sun Feb 08, 2009 8:53 pm Post subject:

If I remember correctly Practical Sailor tested one of these years ago and it was a flop.

Nick
"Valkyrie"

NORO LIM · Posted: Sun Feb 08, 2009 9:00 pm Post subject:

Hmmm, they could either use a little editorial checking on their endorsements, or there's a new radar brand on the market:

"The RADAR FLAG signal was recognizable 360º at full circle from 4 miles by my Fuerno." — Capt. Brad Mutcher, 'The Getaway', Pompano Beach, Florida

I interviewed a job applicant once whose resume claimed he was a member of "Phi Betta Kappa." These kinds of things always make ya wonder.

mcc272 · Posted: Sun Feb 08, 2009 9:34 pm Post subject:

Nick is right about Practical Sailor having tested the Radar Flag and found it to be ineffective.

For a lot of useful technical discussion about radar reflectors, check out http://www.theradarreflectorsite.org/ The guy who does the site has an appropriate technical background and writes for a number of publications on the subject. Of note is that after looking at all sorts of reflectors and doing a very intensive technical analysis, he followed Matt's recommendation and selected a Tri Lens for his own boat.

I have had a Tri lens on several boats and once I install my arch on the CD22, there will be a Tri Lens on it as I boat a lot in inclement weather and at night. I want to be seen but I also agree completely with the idea that a well tuned radar is an especially good tool for understanding what is out there with you. When in doubt, a 90 degree turn will keep you away from approaching trouble and will be immediately visible to other observers using radar. Small degree turns may not get noticed.

morris_rl · Posted: Mon Feb 09, 2009 2:34 am Post subject:

Some of the U.S. Navy cruisers and destroyers are quite a bit more radar stealthy than one might expect, given their relatively large sizes. See:

http://www.fas.org/man/dod-101/sys/ship/weaps/outlaw_bandit.htm

and:

http://www.dtic.mil/descriptivesum/Y2006/Navy/0604757N.pdf

------

...

9243 - OUTLAW BANDIT is a ship signature reduction program, applying radar absorbent material (RAM) to selected areas of a ship's equipment, superstructure, and weapons systems. Passive Counter Measures System (PCMS) enhances ship survivability when used in conjunction with AN/SLQ-32 AND Decoys.

------

Regards,

thataway · Posted: Mon Feb 09, 2009 11:12 pm Post subject:

A comprehensive study of marine radar reflectors was published by the UK Marine Accident Investigation Board:

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

This seems to be very scientific and well documented. One has to consider how much roll and heel that the C Dory will have. When running at speed, it is unusual to have more than 15 degrees roll to ether side. A sailboat may go to 25 degrees regularly.

journey on · Posted: Mon Mar 23, 2009 7:26 pm Post subject:

Just for ducks, here is a radar reflector test, done by SRI Inc., with radar reflectors donated by West Marine, for US Sailing. That is, done by people who understand radar, with radar reflectors that are available, for a sailing orginization. I leave it to you to make your conclusions.

US Sailing Radar Tests

Boris

Grumpy · Posted: Mon Mar 23, 2009 7:44 pm Post subject:

Boris,

That report came out in 1995. I think there is a more recent "indpendent" report that includes other technologies such as the Tri-lens. Now if my memory wasn't so bad I would find it... Idea

Merv

Hunkydory · Posted: Mon Mar 23, 2009 8:15 pm Post subject:

journey on · Posted: Mon Mar 23, 2009 8:28 pm Post subject:

Here's the report that evaluates a Tri-Lens, as well as an active reflector, the Sea-Me. The only reflector which met ISO standard ISO8729 was the Sea-Me. Again, as was stated in the SRI report, the best defense is an active one: Use your own radar>

British Radar Investigation

By the way, radar hasn't changed much since 1995. A passive reflector still is not as good as the cheapest radar ON YOUR BOAT.

Boris

Grumpy · Posted: Mon Mar 23, 2009 8:55 pm Post subject:

Thanks Boris,

That's the one I was looking for.
I agree the laws of physics have remained basically the same for centuries but Engineering finds ways to improve the ways in which we can use them. If not then, even from 1990's you would still be using Loran.
Bottom line when we are talking of boats our size is "Might is right" and we need to keep out of the way of the big guys, not the opposite. That's why I like AIS on top of radar.

Merv

Hunkydory · Posted: Mon Mar 23, 2009 9:28 pm Post subject:

Boris

No disagreement on radar being what I'd rather have if the choice was choose one or the other. Do know when we entered Holkman Bay from Stephens Passage for night anchorage at Tracy Arm Cove was glad we had both aboard. Just before narrow entrace in heavy fog with current and icebergs a small cruise ship broke out of the fog we were about to enter. Would just as soon not meet a cruise ship or be around any other boats in those kind of waters without both our radar and reflector, but where you are really right is at that place the cruise ship would likely not have been able to maneuver even if it could see me and reflector, where as with my radar at least I could maneuver to avoid.

On our first two Alaska Cruises had only the radar. I think of the reflector as being another back up safety item and speaking of safety items, on our 2007 cruise the generator we brought along turned out to be of equel value to the radar maybe even more. I know the discussion here is centered mainly on reflectores but depending on destination and money available there's a faily long list of safety items and their back ups that would be prudent to have along.

Jay

starcrafttom · Posted: Tue Mar 24, 2009 1:41 am Post subject:

The Sea-me is the unit my father has. He has not installed it yet but we plan to this summer and test it on the water. The test looks like he made the right choice. And its not a choice between having radar or having a reflector, get both.

NewMoon · Posted: Tue Mar 24, 2009 8:42 am Post subject:

Years ago in our CD22 we cruised SE Alaska one summer with neither radar nor reflector. Maybe we were just lucky, and very reluctant to leave an anchorage if it was foggy. I imagine we didn't have much of a radar signature.

In our 26-footer, traveling the BC north coast and/or SE Alaska, we have spent as many as several hours underway in fog many times, and have changed course to avoid large ships and tugs with tows, often seen only on the radar screen. Seems to us that cruising north of Port Hardy without radar is fairly chancy, especially later in the summer - the month of Fogust, for instance.

We have a radar reflector much like Hunkydory's Davis Echomaster, also properly mounted in the catch rain position. We were heading east from Elfin Cove along the northern part of Icy Strait in fog, on the way to Glacier Bay, when we got a call from a big cruise ship that was overtaking us. They saw us on their radar from some miles back, and wondered where we were heading. We agreed to move over closer to the north side, and a few minutes later we saw them passing us a mile to our starboard, and then turning in front of us into Glacier Bay, as the fog began to disperse. It seems our simple reflector does work pretty well.

denny-o · Posted: Tue Mar 24, 2009 11:47 am Post subject: Radar returns

Just some general comments on the ability of a small radar reflector to give an enhanced return... For those who doubt the enhanced return just look at driveway reflectors, or the reflective strips on runners shoes and notice how they just blaze in your headlights...
I have a small reflector on a tree in my driveway a quarter mile from the road... As soon as we turn off the road at night that is a brilliant ruby red spot glowing at us...

hardee · Posted: Wed Mar 25, 2009 1:12 am Post subject: catch rain position

Posted by Richard of NewMoon:
"...also properly mounted in the catch rain position." Can someone explain the quoted phrase please. What is it and why is that the "proper" mounting?

thanks for the help here,

Harvey
SleepyC Moon