I suspect that Dyson guessed that planing was necessary for the speeds reported in old accounts. We know better and sprint kayaks that often race at Speed/Length ratios above 2.0 prove that. I have paddled kayaks at S/L above 1.8 and I am a pretty wussy paddler but have never planed. The horesepower problem may never be solved since the Inuit very ungraciously died before we could test them. After Dyson sent me the video I built a model from his lines. When I towed it it simply rolled over on its side rather than plane. Of course, a paddler might have kept it upright. Tough to duplicate a paddler in a pond test tank. :( I my study of native kayaks bKr - 12 had a resistance of 10.11 pounds at S/L 1.52. The best multi chine boat Adney/Chappelle AC - 186 was 9.79 at S/L 1.52. I did not investigate further because KAPER cannot be relied upon at all (Skepticism at all speeds is advised :-) )above 6 Knots. It certainly can't deal with planing. I did try running the Dyson Baidarka through Savitsky's formula. It more or less suggests that the hull is poorly shaped for planing as is the case with every native kayak I have studied. Keep in mind that I still subscibe to Savitsky's definition of planning which kayakers who have done no research consider erroneous. :-) Cheers John Winters *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Nick wrote: >>>>>>>I don't think we need to resort to "exaggeration" to explain the speed accounts. One of the best documented accounts talk about kayaks paddling against a strong current while the observer was sailing up a river. What this account says to me is this sounds like the ideal conditions for surfing. A ship sailing up a river probably has a tail wind as wind tend to go up and down rivers. The current was fairly obviously going down the river. So, wind going up the river, current going down, i.e. opposing wind and current -> great conditions for surfing. If the paddler knows what he is doing, kayaks can sustain speeds over 10 knots in the right following seas. In a race like the Molokai Challenge the record holder averaged 9.4 mph for 32 miles. Winning this race depends heavily on surfing ability. Even I am able to bring a relatively short (greenlandish) kayak up to a GPS measured 12 mph and sustain it for a quarter mile on relatively small non-breaking waves. I am sure baidarkas were designed in such a way that they were capable of surfing. I am sure the Aleuts were skilled enough and strong enough to catch fast moving waves. It sounds like some of the accounts included conditions ideal for surfing. My conclusion is, at least some of the accounts were of kayakers engaged in surfing. I don't see anything about Greenland style SOF kayaks that would make them less capable. In my understanding of "planing" some kayaks will plane when surfing some waves, but I haven't seen any plane solely under human power.<<<<<< I couldn't agree more with Nick here. I might add that a kayaker could also probably take advantage of the slower current and back eddies nearer shore that the sailing vessel couldn't use. They may have even used the sailing vessel's own wake to surf on to keep pace with them going up the river. George Dyson went to extreme lengths in creating theories to try to explain the seeming discrepancy of historical accounts of kayak speeds with the modern day reality of kayak speeds and got a lot of publicity for his theories with articles in the New York Times and TV programs such as National Geographic put on. While I admire George's determination and creativity I think he pretty much got it wrong with his theories that had the bifid bow acting like a ships bulbous bow to cut wave drag and whale oil sealing acting like some long chain polymer molecules, such as WSR301, that when injected in sufficient quantities into water can delay the break-up of laminar flow into turbulent flow. Later after his experiments, that were documented by National Geographic (and that I helped with and video taped), showed that Olympic Gold medallist Greg Barton paddling all out had Dyson's super narrow Baidarka having its bifid bow well in the air as he pushed it to slightly over 8 knots in an all out sprint. (Greg did over 9 knots in his Olympic trainer and 7.9 knots in a Seda Glider I provided that day.) I believe it was very legitimate to use Greg for this task as the Eskimos had been bred to the paddle for many generations and were likely extremely powerful paddlers. Still there is no magic that is going to overcome the physics of the situation. Once it was obvious from those tests that his bulbous bow theory was wrong George decided that the unique shape of the Baidarka stern must have been allowing the Eskimos to plane them. Other than when gravity aided (when surfing on waves) I'd have to say that it would be very unlikely at all and even if someone was strong enough to do so they would not be able to maintain the pace for more than a very short period. Gee, maybe the sailors never noticed that the Eskimos had developed the hydrofoil? When Sea Kayaker published George's earlier theories I wrote a critical letter that was never published. I objected to the conclusions that George drew in hindsight that if there was some advance in drag reduction the Eskimos must had done it first. Getting in the spirit of things I even suggested tongue-in-cheek that the micro-grooves that had been on one America's Cup sailboat one year (and later banned) had also probably been done by the Eskimos first (likely put there by the Eskimo women chewing on the sealskins). Matt Broze www.marinerkayaks.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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