Nick wrote: > It is >possible Derek understands better than he lets on and he is just >being lazy and doesn't want to write a in-depth text on hydrodynamics I talked to Derek about this a while back and he did not have a clue. He may have been lazy in not having a qualified person proof-read his book. Britain has no lack of naval architects who could have set him straight on numerous matters. The problem with facile explanations is that they confuse people. >But a surfing kayak is often planing, in that it's CG has been lifted >and the drag is reduced. The fact that it is only capable of doing it >by getting a power boost from an outside source doesn't change the >way the boat moves through/over the water. So a power boat is a kayak since the way it moves through the water is the same as a boat using a paddle. :-) > Maybe not all kayaks >actually start planing in surf, but those that do so more readily are >faster and generally considered "better" surfing boats. This ability >can be designed into the kayak. "Surfing" and "planing" are not be >the same thing, but they can happen at the same time. These things always cause problems. However, Dr. Savitsky pointed out that the rise in CG during surfing could occur but you could not call it planing any more than you could say a person falling off a building was flying because he generated some lift. The distinction between planing and not planing is the vertical rise caused by the boat's power not an outside source. Why is it important? Maybe only because clarity and precision improves understanding. Consider the confusion over "hull speed", "cavitation", "lift", "sheer", etc. etc. that we have seen on this list. The English language continues to evolve but it evolves to no one's benefit if fosters confusion. Both Matt and Nick have commented on the inappropriate drawing of conclusions about boat types based on limited experience and paddlers would do well to pay heed. Both Matt and Nick try to understand why boats do what they do. I think that goes along way to explaining why people like their designs. Hydrodynamics is like a map. You can wander blindly about and still get to your destination but if you have the map you might get there sooner and without falling into the bog. Of course, you can pick the wrong trail but that does not mean there is no "better" trail. Sorry to see you go Jackie. The professor is despondent. He has taken to his cage and refuses to come out or eat. I have see him in this kind of funk before and it is frightening. I just hope he can dig himself out. 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/ ***************************************************************************
At 9:36 AM -0500 1/17/02, John Winters wrote: > >Nick wrote: > >> Maybe not all kayaks >>actually start planing in surf, but those that do so more readily are >>faster and generally considered "better" surfing boats. This ability >>can be designed into the kayak. "Surfing" and "planing" are not be >>the same thing, but they can happen at the same time. > >These things always cause problems. However, Dr. Savitsky pointed out that >the rise in CG during surfing could occur but you could not call it planing >any more than you could say a person falling off a building was flying >because he generated some lift. The distinction between planing and not >planing is the vertical rise caused by the boat's power not an outside >source. OK, I guess there is a definition out there that precludes using the word "planing" when the boat is "surfing". Can you use "planing" to describe what is happening with a water ski? How about if you put a model of a planing boat in a tow tank? Is the data collected meaningless because the power comes from an outside source? How about one pontoon of a catamaran where it is the other pontoon that has the motor. The source of the power strikes me as a funny way of discriminating how a hull moves through the water. Again, I want to note that I am not saying all surfing involves planing, just that many kayaks do something that looks an awful lot like planing while surfing. There are times surfing on small waves when the wave just pushes the boat along through the water and nothing seems much different from regular paddling accept it is easier (displacement mode?). Then there are times on bigger waves when all of a sudden the boat breaks free and starts flying down the wave, the boat bouncing along the surface instead of pushing through the water. The difference is not just that it is getting a boost in power. The boat noticeably lifts and performs completely differently. This happens at a distinctly noticeable and sudden transition. Am I not permitted to call this "planing" because some portion of the power required to reach that point comes from the wave? If not, not how does one distinguish between the slower push-through-the-water mode, and the faster up-on-the-surface mode? What are the proper words? > >Sorry to see you go Jackie. The professor is despondent. He has taken to his >cage and refuses to come out or eat. I have see him in this kind of funk >before and it is frightening. I just hope he can dig himself out. Give him a couple ballast rocks to throw around for awhile. It might help him work out his anxiety. -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** 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/ ***************************************************************************
On Thu, 17 Jan 2002 09:36:53 -0500 "John Winters" <jwinters_at_onlink.net> wrote: > >These things always cause problems. However, Dr. >Savitsky pointed out that >the rise in CG during surfing could occur but you could >not call it planing >any more than you could say a person falling off a >building was flying >because he generated some lift. The distinction between >planing and not >planing is the vertical rise caused by the boat's power >not an outside >source. You seem to imply that nothing can "fly" without an internal power source. I disagree with that; sailplanes, hang gliders, and even balloons do fly, despite having no internal power source. Despite a "flying suit" on a skydiver I once saw, I would say that flying requires that most of the weight of the object to be supported by the air - either by buoyancy or lift (and not by drag, so we can rule out terminal velocity falls). I would not require that all the weight be supported by buoyancy or lift, as there is some drag weight support for any flying object in a descent, but certainly the vast majority of it. Continuing this analogy to planing suggests that we need only require that the great majority of the boat's weight be supported by hydrodynamic forces on the hull and not by static displacement, and need not depend on internal power sources. Agreed, some measurable rise in CG doesn't get us there, any more than some measurable lift converts falling to flying, but if not planing, what do you call it? And how does it differ for a sailboarder, who also has no internal power source? I have often heard that described as planing. *************************************************************************** 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/ ***************************************************************************
From: "Bob Myers" <bob_at_appereto.com> > You seem to imply that nothing can "fly" without an > internal power source. I disagree with that; sailplanes, > hang gliders, That's gliding, not flying. Flight requires power. > and even balloons do fly Bouyancy, not flight. > And how does it differ for a sailboarder, who also has no > internal power source? I have often heard that described > as planing. Power comes from the sail as it does in planing sailboats. The International Sailing Canoe I mentioned in a recent post is a sail-powered planing vessel. Again we see examples of where a layman's term differs from a specialist's. Specialists require exactness in terminology and will use terms in specific ways. Two subtly different phenomena are referred to by the specialist with distinct terms so inter-specialist communication is clear. Mike *************************************************************************** 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/ ***************************************************************************
Yes, there are certainly differences between the specialist's teminology and the layman's, and I feel that more specialists must recognise that when communicating with the layman that the layman's terminology will have to take precedent. Especially in the case where the word was in general usage before the specialists took it over and came up with their own precise definition. Engineers can come up with a very precise definition for "hull" but that doesn't mean that when I refer to a "walnut hull" that I have to be refering to a stripper made with walnut. And as for "fly" according to my dictionary it applies to birds, planes, flags, kites, bullets, spacecraft, etc. It says nothing about under it's own propulsion. The definition of plane in my dictionary is "to rise partly out of the water while in motion at high speed." And that is how I have always used the term, therefore get websters corrected before correcting me. Dave Michael Daly writes: > Again we see examples of where a layman's term differs from a > specialist's. Specialists require exactness in terminology > and will use terms in specific ways. Two subtly different > phenomena are referred to by the specialist with distinct terms > so inter-specialist communication is clear. *************************************************************************** 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/ ***************************************************************************
Michael Daly wrote: >Again we see examples of where a layman's term differs from a >specialist's. Specialists require exactness in terminology >and will use terms in specific ways. Two subtly different >phenomena are referred to by the specialist with distinct terms >so inter-specialist communication is clear. English is a varied and complex language with many of it's words having definitions that can vary dependent on context. While I can understand the sentiment defined above, some or our more technically inclined brethren seem to be putting their own spin on the words of others. That a layman might use a term, which in an engineering frame of reference has a specific and technical meaning, does not necessarily mean that the layman was speaking to that frame of reference. That the layman does not call out the frame of reference that they speak from does not, in and of itself, make them wrong. Feel free to correct and to ask that people clarify their terms but please be as thorough with your understanding of the breadth of our language as you ask the layman to be with the technical definitions of terms that have special meaning to you. Definitions which, by the way, may not be readily available to the layman. My Webster shows 16 definitions for plane, among them are; 1) to glide or soar 2) To rise partly out of the water at high speed Based on the above definitions, I fail to see where any layman has used a term incorrectly in this recent thread. Communication is only as clear as the motivation of those involved allows it to be. Previous posts have stated that even incorrect models can yield correct results. I wonder if some of our "technically inclined" understand that they too are just defining the physical world from within a model. A model with much mathematical weight behind it, but a model just the same. There was a time when there was "scientific proof" that the world was flat. Jed *************************************************************************** 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/ ***************************************************************************
From: "Jed" <jluby_at_teamnorthatlantic.com> > Based on the above definitions, I fail to see where any layman has used a > term incorrectly in this recent thread. I guess my point was not made clear at all. My fault. Bob's examples differ from the specialist's when viewed with the specialist's terminology. That is, while he sees flying as including both flying and gliding, the specialist differentiates the two. So to is John trying to differentiate between surfing and planing, to a degree that most people won't. While the difference is irrelevant for many, to the specialist, it is significant. That does not make Bob wrong, nor does Bob's generalization make John's comments wrong. They are simply looking at things using the same terms with different degrees of refinement. Given the points that John is trying to make, we must consider the discussion from _his_ point of view, otherwise we'll miss the issue entirely. I personally look forward to discovering the significant differences between surfing and planing from the expert's perspective. My apologies to any who took offence. Mike *************************************************************************** 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/ ***************************************************************************
Michael, I guess, I made a bit of a mistake in my reply. While editing it before sending I deleted the paragraph where I said that I was agreeing with you. I was just trying to expand on it and make the point that the responsibility lays with those that have the uncommon usage to make their point clear when they are not talking to someone who has not already agreed to their limited usage. Michael Daly writes: > I guess my point was not made clear at all. My fault. Bob's examples > differ from the specialist's when viewed with the specialist's terminology. > That is, while he sees flying as including both flying and gliding, the > specialist differentiates the two. Then the specialist had best not tell the non-specialist that they are wrong. The specialist is wrong to do so if all the people in the communication have not previously agreed to the limited terminology. > So to is John trying to differentiate between surfing and planing, to a > degree that most people won't. While the difference is irrelevant for > many, to the specialist, it is significant. And this is often the problem with specialist communication. They will take a term that is in common use and try to define it. They should come up with a term that does not already have a common usage. > That does not make Bob wrong, nor does Bob's generalization make > John's comments wrong. They are simply looking at things using > the same terms with different degrees of refinement. Given the > points that John is trying to make, we must consider the discussion > from _his_ point of view, otherwise we'll miss the issue entirely. Agreed to a point. The problem is when John tells Bob that he's wrong. This has happened many times on this list that things heat up over different terminology and people are actually agreeing. It would also be inappropriate for me to tell John that his definitions are wrong. They are the definitions that are used in his field and appear to be well defined. I think it would have been a better choice to have used other terms than to try and limit the definitions of words already in common usage, but it's too late for that now. > I personally look forward to discovering the significant differences > between surfing and planing from the expert's perspective. I wholeheartedly agree! I would love to find out WHY there is even a difference if the result is what I perceive to be the same. > My apologies to any who took offence. I certainly didn't take offence. I was meaning to agree with most of what you said. Dave *************************************************************************** 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/ ***************************************************************************
On Fri, 18 Jan 2002 00:30:09 -0500 "Michael Daly" <michaeldaly_at_rogers.com> wrote: >From: "Jed" <jluby_at_teamnorthatlantic.com> > >I guess my point was not made clear at all. My fault. > Bob's examples >differ from the specialist's when viewed with the >specialist's terminology. >That is, while he sees flying as including both flying >and gliding, the >specialist differentiates the two. Oh come on now. If we restrict "flying" to what might otherwise be more specifically called "powered flight", then replacing the plummeting person with a high-performance sailplane in John's example destroys it as a reductio ad absurdum argument, which is how John was trying to use it. Imagine the following absurdity instead: However, Dr. Savitsky pointed out that the rise in CG during surfing could occur but you could not call it planing any more than you could say high-performance sailplane on a cross-country "flight" of a few hundred miles was flying because it was supporting its weight by generating lift, since it is not internally powered. Do you see the problem? And we still have the other absurdity of why a sailboat can plane but a surfing kayak cannot. A sail is not an internal power source by any reasonable definition. Why is wind power more like internal combustion engine power than it is like wave (surf) power? *************************************************************************** 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/ ***************************************************************************
From: "Bob Myers" <bob_at_appereto.com> > On Fri, 18 Jan 2002 00:30:09 -0500 > "Michael Daly" <michaeldaly_at_rogers.com> wrote: > > > >I guess my point was not made clear at all. My fault. Bob's examples > >differ from the specialist's when viewed with the specialist's terminology. > >That is, while he sees flying as including both flying and gliding, the > >specialist differentiates the two. > > Oh come on now. If we restrict "flying" to what might > otherwise be more specifically called "powered flight", > then replacing the plummeting person with a > high-performance sailplane in John's example destroys it > as a reductio ad absurdum argument, which is how John was > trying to use it. Bob, all I can say is that I think you're getting caught up on the semantics. The fact is that an aerodynamicist will differentiate between powered and non-powered flight. I know, I used to work with them. Two of my bosses were competitive sailplane designers and builders. One was very picky about terminology and would correct me if I used a powered aircraft term where a sailplane term was more appropriate. The fact that the layman doesn't differentiate doesn't negate the value of what the experts do. John's points revolve around the _need_ for specialists to make the differentiation. The fact that we can't see the difference in our day-to-day lives doesn't devalue that. Please, let him make his point. Mike *************************************************************************** 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/ ***************************************************************************
From: "David Anderson" <squtch_at_quiet-like-a-panther.org> > I was just trying to expand on it and make the point that the responsibility > lays with those that have the uncommon usage to make their point clear when > they are not talking to someone who has not already agreed to their limited > usage. Agreed. > > So to is John trying to differentiate between surfing and planing, to a > > degree that most people won't. While the difference is irrelevant for > > many, to the specialist, it is significant. > > And this is often the problem with specialist communication. They will take > a term that is in common use and try to define it. They should come up with > a term that does not already have a common usage. In many cases, the specialist's use of the term precedes the use of the term among the general public. The general public didn't know much about boats or aircraft until after the specialists have done a lot of the groundwork. In the case of planing/surfing concepts, the theory predates the general public's ownership and usage of such craft. Prior to the second half of the twentieth century, only the rich could afford high performance vessels. Once in the general public, the terms get undifferentiated. The French are noted for trying to invent "pure" French words for technical terms (as opposed to borrowing them from other lanquages). They are often ridiculed for the attempt. Having been born and raised in Quebec, I'd be leary of going this way - but let's not get into that. > Agreed to a point. The problem is when John tells Bob that he's wrong. This > has happened many times on this list that things heat up over different > terminology and people are actually agreeing. Hey, I've done that! :-) Mike *************************************************************************** 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/ ***************************************************************************
-----Original Message----- From: Michael Daly In many cases, the specialist's use of the term precedes the use of the term among the general public. The general public didn't know much about boats or aircraft until after the specialists have done a lot of the groundwork. In the case of planing/surfing concepts, the theory predates the general public's ownership and usage of such craft. Prior to the second half of the twentieth century, only the rich could afford high performance vessels. Once in the general public, the terms get undifferentiated. -------------------------- Are you saying that the specialists coined these phrases, invented these words? I would be very interested in one or more examples of this, or better yet many examples. Lift, plane, surf, length, flight, these are not words that come from the mind of a specialist. Derivations as listed in Websters College Dictionary: Lift [1250-1300; ME < ON lypta der. of lopt air, c.MHG luften; cf. loft] Plane [1400-50; n, adj) < L planus flat; ME planen (of a bird) to soar Surf [1675-85; earlier suff; of uncertain origin] Length [before 900; ME length(e), OE lengthu . . . ] Flight [before 900; ME; OE flyht; c OS fluht; akin to fly] Hopefully you see that is not uncommon for the specialists to take a word in common usage and adapt it's use to specify a meaning unique to their field of interest. Certainly you don't think you can admonish us by committing the very crime of which we stand accused. We don't seek to limit your use of our words, but we to take umbrage when you attempt to say that it is we who cheapen their value. Use our words, freely and with our blessing, but when you decide that these words no longer mean that which they have meant for centuries please be kind enough to preface your use with a reference to a specific field of interest. Jed, certified non-specialist PS Any attempt to be offended by the above shall be prosecuted to the fullest extent of the law. *************************************************************************** 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/ ***************************************************************************
From: "Jed" <jluby_at_teamnorthatlantic.com> > Are you saying that the specialists coined these phrases, invented these > words? No, I'm saying that the use of these words in specific ways and in specific contexts often precedes their later being garbled by the masses in the same contexts. No one talked about aircraft until after the specialists created them. How many laymen use the term "empennage"? This is much more specific than the terms that laymen use for the same thing(s). In fact, when I hear laymen talk about this, their terms are often confusing and/or incomplete. Lacking the term empennage, they end up using many of the other terms aircraft specialists use. When I talk of memory in a computer, I usually preface it with a reference to disk, RAM, whatever, when the context isn't clear. However, it still confuses many laymen who don't differentiate the kinds of storage available in the box in front of them. The techies invented these terms, and yet they are misused and confused by lots of people. The box is often referred to as a CPU, when in fact the CPU is a small chip buried deep inside the box. There is no clear dividing line between these things. But as an engineer and technologist, over the decades I've seen many examples of people taking umbrage at being asked to communicate clearly and logically in certain fields. As Arno Penzias said "Logic is cumbersome, that's why so few people use it." This applies to language, where being vague is preferred by those who don't have the confidence in an area to try to be specific. Confusing planing and surfing, flying and gliding etc. removes the requirement to be specific and focused. Language is great that way. You can be as specific or vague as you want and still be deemed to be communicating. Ask any politician. :-) > We don't seek to limit > your use of our words, but we to take umbrage when you attempt to say that > it is we who cheapen their value. I think the problem is the other way around. We seek to add value to them and this is rejected by "the masses" who prefer the confusion of not being specific. > Use our words, freely and with our > blessing, but when you decide that these words no longer mean that which > they have meant for centuries please be kind enough to preface your use with > a reference to a specific field of interest. Your point about specifying the context is well taken. I think that John has tried to do this, specifically by introducing a reference to a specialist in the field. The complaints have been that being this specific is "bad." Mike *************************************************************************** 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/ ***************************************************************************
From: "David Anderson" > > From: "Michael Daly" <michaeldaly_at_rogers.com> > > > Again we see examples of where a layman's term differs from a > > specialist's. > > And as for "fly" according to my dictionary it applies to birds, planes, > flags, kites, bullets, spacecraft, etc. It says nothing about under it's own > propulsion. As a layperson, I haven't a clue what a "specialist" would say in place of "go fly a kite" 8-) _______ /| /| / |____/ | /______/ | | | /| |______|/ | | | | /| |__|___|/ / | | / \ / |______|/ | / \ / / \ | / __ / ___ / __( ( / )_ _( )___ \ | / _( ( / ) __ _( )__ _( / _( ) ______ ( ) ( / ( )_ ( ( )__ / __( ( ) _________ _( ______( ) / _( ( ) (___ _ ___) / ( ) / | (___ / _ ( _ _ ) / (_____ __ _(_ _ _ ) _ _ / | / \ / \O/ \ | /_ " / / \ | / \ / / / / __ __ / _ _ _ ///\wVw/\\\ / \\ / \0/ \ ////|\\\\ / \\ " /// Y \\\ / `\ (((/v\))) / _/ \, //"\\ {"} (/",o /{) _ ///|\\V/ / (_at___y// \ ||\///"\\\/|| [ [.`,___\ \\\\||"||//// [___`----+) \--mm-`mm"----mm------+---+-----\---------------') ~~~~jf~ ~~~~ ~~~~~~~~~ ~~~~~~ ~~~~~~~ ~~~~\~ ~~~~ ~~~~~~~~~ ~~~ o \ o o \\ o o \\ o ` (\ o o >jf:-) o (/ o o o *************************************************************************** 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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