Chuck Sutherland wrote, "A group of us once paddled in heavy fog among islands on the coast of Maine. A Coast Guard boat loomed up from the mist and suggested we stay out of the channel. They said we were only barely detectable with their hotshot radar, and would likely be entirely undetectable by average marine radar systems on private yachts. We encountered this patrol in an area of dead flat calm water." Chuck has asked about ideas on radar visibility for kayaks. We have bounced this subject around before on PW, and there was a pretty comprehensive article done in Sea Kayaker a while back --- don't have the date --- which, from memory, indicated that there were no viable means to enhance a kayak hull's radar cross-section, its radar visibility to an oncoming ship; however, there are commercial metal or metalized foam three dimensional radar reflectors available at boating supply stores (~$15-20) which, if mounted on a nominal four to six foot mast on the after deck of the kayak, will provide some enhanced passive visibility for a kayak. (All this assumes that an oncoming vessel operator is (1) looking at his scope, and (2) is seriously concerned about a very small blip on his screen --- the argument being that he may be far more concerned about a blip indicating the presence of something bigger and meaner than himself --- like Nova Scotia or something. But that's a different thread.) An option to this for deep-pocketed kayakers --- or maybe trip operators or instructors with insurance concerns --- is a Search and Rescue Transponder (SART). SARTs basically monitor radar frequencies and, when they are swept by a radar signal, answer back to that radar transmitter that there's something there. You will not resemble a Canadian province, but you will certainly indicate your presence to the oncoming vessel. Re the "deep pockets" issue: a SART is going to run between $1200 and $1500 (US). A cheaper option is one of the inflatable assistance widgets sited in Sea Kayaker in April 1998, the Sea Bouy (see www.seakayakermag.com/apr98/inflatdev.htm). This is a diver's device which inflates into a four foot international orange cylinder with retroreflective tape at the top and a radar reflective element in the top. Mounted to a kayak's rear deck, this widget could provide a quick inflating "mast" and some passive radar protection (said to provide a one mile indication in an independent boating magazine's test). The price tag on this guy is somewhere around $100 (from memory). Again, the oncoming vessel has to be looking and concerned --- both big assumptions. (And this doesn't even address the idea of recovering the kayak from a knock-down with a six foot mast or a four foot inflatable cylinder above your after deck! Other serious safety issues here.) Bottom line: I have used boat store radar reflectors in nighttime tests of search and rescue (SAR) equipment in open ocean scenarios in the past; mounted to a bouy at a nominal three foot height above water level in two to three foot seas, these things were marginally effective inside a one mile radius --- and we were definitely watching for them on the vessel's radar because they were attached to several thousand dollars worth of equipment which we wanted to recover at the end of the evening! My guess is that passive radar reflectors at heights above water which a kayak could conceivably provide would be, at best, marginal. Better than nothing? Sure. Good if the Coast Guard is out there actively searching for you? Definitely. Valuable to a kayaker skirting or crossing a channel in fog? Dunno --- wouldn't bet my life on it. Better bet? A SART for the instructor's boat, keeping the flotilla in close formation. Best bet? Stay out of the fog altogether. My somewhat more than two cents. Jack *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Thu Oct 21 1999 - 06:56:14 PDT
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