I know this has been probably discussed before, so a quick summary would be great. Exactly how visible are kayakers to radar? I am guessing that kayakers without any kind of radar-refelcting special equipment are completely invisible to even the best coast guard or land based radar. Does this change appreciably with a head or deck mounted radar reflector? Thanks, kevin ------------------------------- | Kevin Whilden | | kwhilden_at_seanet.com | | Kayak Academy Instructor | | http://www.halcyon.com/kayak | ------------------------------- *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
According to Derek Hutchinson's book, the radar reflectors he and his friends used were not very effective. He says that a pole with a ball of aluminum foil wrap at the end is a much better reflector than a standard reflector sitting on the deck. There is one gadget call transponder. It detects radar signals, and sends answers--rather than reflecting the same signal back. Some buoys have them. While it sound like a very powerful solution, I have not seen any studies or reports on the use of transponders in kayaks. - Julio > Does this change appreciably with a head or deck mounted radar reflector? > kevin *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
On Mon, 4 Oct 1999 juliom_at_cisco.com wrote: > According to Derek Hutchinson's book, the radar reflectors he and his > friends used were not very effective. He says that a pole with a ball > of aluminum foil wrap at the end is a much better reflector than a > standard reflector sitting on the deck. I've been saving one of those wine-box bladders of aluminized(?) mylar to put on a paddle blade as a radar reflector. Would that work? e Elaine Harmon - eilidh_at_dc.seflin.org - eharmon_at_cs.miami.edu *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
> I've been saving one of those wine-box bladders of aluminized(?) mylar to > put on a paddle blade as a radar reflector. Would that work? e > Elaine Harmon - eilidh_at_dc.seflin.org - eharmon_at_cs.miami.edu Radar reflectors are made of several surfaces perpendicular to each other. The effect of this arrangement is that radar waves are reflected back in the same direction in which they came. You can try this effect on a pool table--throw a ball to a corner so that it bounces on two walls, and see how the ball comes back in a direction paralell to the initial throw. An aluminized paddle blade would only be visible to radar if it happened to be a the right angle when the radar antenna points at it; this is very unlikely. Now some food for thought. Why do kayakers need to be visible to radar? A ship that navigates by radar is probably to big and restricted to do anything about that little dot in the screen that is not supposed to be there. Would it not be better for us kayakers to have radar and become aware of big ships in fog long before they pass over us? my two cents, - Julio *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
On Tue, 5 Oct 1999 juliom_at_cisco.com wrote: > Radar reflectors are made of several surfaces perpendicular to > each other. The effect of this arrangement is that radar waves > are reflected back in the same direction in which they came. Aha! So you'd have to have a bent wire structure inside that would turn it into a rotating vane, to be hoisted up on the shaft under the blade. But then you couldn't paddle and hold it up. A shock-corded light Al tent pole? Strapped to the paddler's back? Maybe I just won't paddle in fog. e Elaine Harmon - eilidh_at_dc.seflin.org - eharmon_at_cs.miami.edu *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
Kevin, Based on my limited experience on the other side of this issue (I spent a week driving a 38' radar equipped fishing boat in Puget Sound and the Straight) ... I had the joy of piloting the boat into the Straight (while the owner downed a bottle of vodka) with fog so thick you could not see 25 yards. Kayaks and canoes are 100% invisible. Rocks and other things sticking out of the water less than 2 ft. are barely visible on radar, and may become invisible as the boat approaches them. Sailboats are totally visible, with or without radar reflectors. The masts and cables give a great reflection. I was able to steer around a sailboat in the Straight using the radar and I can tell you honestly that without it we would have collided, absolutely without question. Radar reflectors on small motorboats seemed to make no difference I could notice. There are lots of small sparkles on the screen (from waves, etc.) and making a small intermittent reflection is useless. One time I saw a boat appear and disappear on radar while in perfect visual sight the whole time. My belief was that the radar was picking up the broad side of a 5 gallon gas can on his deck when he was at just the right angle. I suspect reflective coating on your paddle would have this same effect ... being bright for a moment, then disappearing. >From my limited technical knowledge of the subject, anything metal with a variety of 3-dimensional right angle corners pointing in all directions makes a decent reflector but it has to have decent size and it has to be up high enough to be seen by the radar antenna on the boat, which is generally up around 8 or 10 feet minimum. A crunched up beer can or ball of foil atop a bicycle flag or fishing pole might be effective, in my view. By the way, most radar users are absolutely untrained. My training was, "turn that breaker on before you turn the set on. There, OK." I think from conversations with other boaters that this is about average. And I think the bottle of vodka was about average too, and the fact that one sober person was on board all week was the exceptional part. You have to license a bicycle here, but to drive a 38 foot twin engine behemoth, or a 65 knot jetski, nothing. jerry. K. Whilden wrote: >I know this has been probably discussed before, so a quick summary would >be great. Exactly how visible are kayakers to radar? I am guessing that >kayakers without any kind of radar-refelcting special equipment are >completely invisible to even the best coast guard or land based radar. >Does this change appreciably with a head or deck mounted radar reflector? >Thanks, >kevin > ------------------------------- > | Kevin Whilden | > | kwhilden_at_seanet.com | > | Kayak Academy Instructor | > | http://www.halcyon.com/kayak | > ------------------------------- > >*************************************************************************** >PaddleWise Paddling Mailing List >Submissions: paddlewise_at_lists.intelenet.net >Subscriptions: paddlewise-request_at_lists.intelenet.net >Website: http://www.paddlewise.net/ >*************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
While taking a tour of one of the new Puget Sound ferries, I questioned the 1st Officer about the effectiveness of their radar(s). He stated that their radar would NOT pick up ANYTHING close to the water even if it was a reflecting surface. He stated that they were unable to "see" small (14-16 foot) aluminum open fishing boats with outboards. >From his comments, I inferred that increasing the radar reflecting cross sections of a kayak without using some sort of a mast to elevate the reflector, would be a waste where other vessels are concerned (I am not speaking of downward looking radar from aircraft)... Eric -----Original Message----- From: juliom_at_cisco.com [mailto:juliom_at_cisco.com] Sent: Tuesday, October 05, 1999 11:25 AM To: paddlewise_at_lists.intelenet.net Subject: Re: [Paddlewise] radar signature > I've been saving one of those wine-box bladders of aluminized(?) mylar to > put on a paddle blade as a radar reflector. Would that work? e > Elaine Harmon - eilidh_at_dc.seflin.org - eharmon_at_cs.miami.edu Radar reflectors are made of several surfaces perpendicular to each other. The effect of this arrangement is that radar waves are reflected back in the same direction in which they came. You can try this effect on a pool table--throw a ball to a corner so that it bounces on two walls, and see how the ball comes back in a direction paralell to the initial throw. An aluminized paddle blade would only be visible to radar if it happened to be a the right angle when the radar antenna points at it; this is very unlikely. Now some food for thought. Why do kayakers need to be visible to radar? A ship that navigates by radar is probably to big and restricted to do anything about that little dot in the screen that is not supposed to be there. Would it not be better for us kayakers to have radar and become aware of big ships in fog long before they pass over us? my two cents, - Julio *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ *************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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