Matt wrote in response to Richard Culpepper; >Show me the evidence! This is good advice. So much of this debate hinges on faulty logic, opinion, specious arguments and flawed "research". I know Matt won't mind my using his post as an example since I know he welcomes constructive criticism and won't take it personally. As I pointed out in a previous post some of Matt's arguments lacked objective support (3,4,7,12,14 and16), some used specious logic (1,2,5,8,9,13,and 15) and some used flawed data (6). Suitable objective testing to support these arguments would go a long way and be enormously useful. The important thing is to recognise that a poorly designed or built rudder is not a suitble foundation for their condemnation. Of course, the opposing side isn't any better. Paul Caffyn is a good story but his story is anecdotal and only applies to him and his particular experience. It is certainly not a universal recommendation for rudders. Obviously the personal preferences of paddlers are just that - personal, and most arguments in favour of rudders hinge on personal preference. Like the opposing view they lack objective support. However, because there is so much support for Richard's points they are useful. Most designers of sprint kayaks actually do the research (although they are not keen to publish it for obvious reasons), have done tank testing and controlled real life testing and have found that there is a net improvement in performance using a rudder. Experience in the hotbed of competition supports this. Of course, as Matt points out, the seem specific to one type of boat in very specific conditions. It would be good to have data that crossed those boundaries. One of the things that is not mentioned when comparing rudders vs heeling is that, while the rudder adds resistance so does heeling the boat. The heeled boat changes shape and form parameters and not usually to the benefit of resistance. The amount of added resistance varies considerably from boat to boat but it exists and is measureable. Unfortunately, Sea Kayaker did not test their kayaks heeled like we do when testing sailboats. It would also be nice if we could actually measure the added effort needed to keep a boat on course with a paddle and by leaning. Then we could put that part of this debate to rest. In the meantime I suppose this kind of inconclusive discussion does prompt people to think about what they might want in a kayak. For me no rudder is the best rudder but some of my friends consider me a Luddite and they may be right. :-) 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/ ***************************************************************************
A couple of items. On 6/29/07, John Winters <jdwinters_at_eastlink.ca> wrote: Suitable objective testing to support these > arguments would go a long way and be enormously useful. "Suitable" is the operative word here. Short of putting a paddler in a suit that has been completely set up to measure effort (strain gauges everywhere I suppose), and into a kayak that has been prepared the same way, I can't think of a way to do "objective testing". And anyway, what constitutes objecting testing? Many of us seem to feel that the only objective results can come from some form of test. But for a long time scientists had only empirical evidence to use. Biology, especially, has been built on a foundation of empirical (observed and recorded) evidence. > Of course, the opposing side isn't any better. Paul Caffyn is a good story > but his story is anecdotal and only applies to him and his particular > experience. Caffyn's story is only "anecdotal" in the sense that he was not a trained scientist and the data was not the focus of his efforts. If, as I understand it, he kept a daily log with miles covered and hours paddled that stretched over years then that would be empirical evidence. Anecdotal evidence is more closely associated with patient reports of the side effects of drugs or hearsay. Caffyn's logs would not be considered anecdotal in that sense. Now if he said, "I'm pretty sure I paddled farther with a rudder than without one" then *that* would qualify as anecdotal evidence. Nor would Matt's evidence, which is essentially in the same form but more detailed, be considered anecdotal. Matt's records, like Caffyn's form empirical evidence which can be reduced to statistical evidence by careful anaylysis. Any careful record of results gathered over a long period of time would not, in my opinion, be considered anecdotal even when collected by a "non-scientist". Once you have enough empirical data (the numbers of bird species inhabiting one area every December times the number of areas under observation times however many Decembers this happened, for instance) you can then reduce that to statistical evidence. Paul Caffyn's records gathered over thousands of miles of paddling over several years would be no less anecdotal than the annual bird count. And, just as the decline of a species over time can be documented this way, so can an increase of miles paddled after a modification to the same vessel. Caffyn's records obviously apply only to him, his boat, and his experience. But the statistical differences seem to be clearly caused by the modifications to the boat. Certainly Caffyn thinks so. Now, if we had 4 Paul Caffyn's paddling 4 different boats under similar conditions for the same period of time, then that would allow us to compare the results. Unfortunately, we only have Paul Caffyn. But his empirical records lead to a compelling statistical result: He covered more miles in less time with a rudder than without. It is certainly not a universal recommendation for rudders. Well, it says nothing about how a rudder would help someone in a rock garden or surfing but it's certainly evidence that for point-to-point paddling the same boat paddled by the same person can go farther with a rudder than without. And it's not anecdotal. > Obviously the personal preferences of paddlers are just that - personal, > and most arguments in favour of rudders hinge on personal preference. Like > the opposing view they lack objective support. Actually, this is not the case. Empirical evidence collected by an expert (does anyone think Paul Caffyn is not an expert paddler?) is considered to be objective; partly because it can be repeated. All you and Matt have to do is, say, paddle around Australia in any boat you choose. Paddle half way without a rudder and half way with a rudder. Keep a record of how far you went every day and how long it took. At the end we'll have a much better picture of whether a rudder is helpful for point-to-point paddlling. However, because there is so much support for Richard's points they are > useful. Most designers of sprint kayaks actually do the research... (but) > ...as Matt points out, the (sic) seem specific to one type of boat in very > specific conditions. It would be good to have data that crossed those > boundaries. We do have data that crosses those boundaries. Paul Caffyn's data. I'm not sure why you so casually dismiss it. Craig Jungers Royal City, WA *************************************************************************** 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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