I use a racing sit on top, a surf ski, made by Venture sports-Bruce gibson. Its 19.5 feet long, very narrow, and very fast. Its stable as long as you paddle, particularly if you use the far more efficient and much faster WING PADDLES, which provide more lateral stability as well as more efficient thrust. Because my boat is made to be fast, it likes to track straight, and while it "can" be turned by leaning, this would be a poor way to control it, and would fail if high wind conditions arose ( over 25 or 30 mph winds--we do get that here in WPB Florida). Since I use my boat to paddle out to the reefs about 1.5 to 2 miles from shore, where I freedive ( deep snorkelling), this can become a real issue. A rudder is CRITICAL in this type of "surf ski" design. And, coming back in to shore, if the winds have picked up a lot since I went out ( also typical from 8am to 12noon) , the large waves that begin to roll in, become helpful to me on my return trip to shore, with the help of the rudder-----the bigger waves ( over 7 feet, but not too steep) can be used to actually "surf" in, the boat riding each large wave you catch for many minuutes at a time. with steep waves, it gets harder to catch them, and they dissapate sooner. Your return to shore can average 10 to 12 mph, instead of the surf ski paddling speed I average of about 6 to 6.5 mph on the way out. Without the rudder, this "surfing" would be impossible for this type of boat. As to my frequency of paddling, I do this every week on saturdays or sundays for a month or so, then go a month doing more cycling or something else, and then go back to the freediving and kayaing. Regards, Dan > Now that the subject's been raised, who uses rudders and who leans >the boat? > > My Current Designs Solstice GTS has a rudder, but I've never used >it. I bought the boat slightly used from Pacific Wave where it was the >"extra" trip boat for a while for the "in crew" at the shop. . . I don't >think the rudder's ever been used. > > The Solstice GTS tracks in all seas, and doesn't broach or windcock >much. > > Anyone want to keep score on this one? > >*************************************************************************** >PaddleWise Paddling Mailing List >Submissions: paddlewise_at_lists.intelenet.net >Subscriptions: paddlewise-request_at_lists.intelenet.net >Website: http://www.gasp-seakayak.net/paddlewise/ >*************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
I don't think anyone has a problem with rudders on a surf ski! BTW, what do you do about the current? After an hour or 2 of diving you nust be half way to North Carolina heh heh... cya Bob Denton Vice President Undersea Breathing Systems bob_at_dnax.com http://www.dnax.com *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>I don't think anyone has a problem with rudders on a surf ski! > >BTW, what do you do about the current? After an hour or 2 of diving >you nust be half way to North Carolina heh heh... > >cya >Bob Denton Hi Bob, If we paddle out to the extreme South end of Breakers 60 foot reef, we get about an hour. But if we paddle out from the Lake Worth pier ( public beach) and go straight out, we are at the south end of Horseshoe, which is THE best reef we have for freediving, and the current is slower this far south---we can stay over it for 2 hours easily, ending up on Pauls Reef. Then, you do a surface rest, floating in the Gulfstream current for about 30minutes, eating and drinking water---and about this time you are near the beginning of the Breakers Reef system. After another hour on Breakers, you paddle in to the Breakers Resort, check out the 20 to 30 foot reef, and then go south about 400 yards to one of the access points to the public beach. Here someone needs to have a cell phone in a dry bag, and have someone get a few of us back to our cars. This is a drift of what---10 miles? Regards, Dan *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Fri, 27 Mar 1998, Bob Denton wrote: >> >>I don't think anyone has a problem with rudders on a surf ski! i don't have a problem with rudders on anything, you should have seen the size of them on my aircraft carrier ;-) i'm afraid some folks took my semi-anti-rudder statements wrong. it's bad to the "real" underlying arguement, reliance on gadgets, etc, instead of skill. the first things someone in a canoe learns is how to steer a boat, through strokes and leans, etc. canoes aren't much different from kayaks, from an underwater stand point. a canoeist has to learn how to control a boat, using one paddle on one side of the boat [generally] whereas a kayak has two paddles, one on each side of the boat. i watch my poor daughter paddle her new sea kayak, and realize she never sat in the stern of the canoe [well, she weighs 75# and i'm 200#, so i makes it hard] she can't do any stern strokes, so she spends half her time back paddling on one side to straighten back up, and now she's 15, so she won't even listen when i suggest a stern pop/pry ... many solo canoes are straight keeled, 17' long, and they're not equipped with rudders, nor do canoeists insist on one ... why do sea kayakers?? johnw, you design both ... what are your thoughts [and i duck and run awaya again ;-)] >> >>BTW, what do you do about the current? After an hour or 2 of diving >>you nust be half way to North Carolina heh heh... or his boat is ;-) >> >>cya >>Bob Denton mark #------canoeist[at]netbox[dot]com-------------------------------------- mark zen o, o__ o_/| o_. po box 474 </ [\/ [\_| [\_\ ft. lupton, co 80621-0474 (`-/-------/----') (`----|-------\-') #~~~~~~~~~~~~~~~~~~~~~~~~~~~_at_~~~~~~~_at_~~~~~~~~~~~~~~~~~~~_at_~~~~~~~~_at_~~~~~ http://www.diac.com/~zen/cpr [Colorado Paddlers' Resource] http://www.diac.com/~zen/rmskc [Rocky Mtn Sea Kayak Club] http://www.diac.com/~zen/rmcc [Rocky Mtn Canoe Club Trip Page] http://www.diac.com/~zen/mark [personal] -- Fortune: The goal of science is to build better mousetraps. The goal of nature is to build better mice. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Bob wrote; re: rudders > >johnw, you design both ... what are your thoughts [and i duck and run >awaya again ;-)] There are people who need rudders no matter what boat they paddle.They lack the skills or physical ability to handle a boat without one. There are boats that need rudders because their design is such that they cannot be held on course or manoeuvred without one. There are people who have sufficient skills to handle a boat without a rudder. There are boats that are designed in such a way that a paddler can easily learn to handle the boat without a rudder. I do not design boats with rudders because I expect the customer to learn the appropriate skills. however, I can understand the reasoning behind designing boats with rudders for those people who may not want to learn those skills or have a physical barrier to doing the required strokes. Whether a rudder is desirable depends upon the persons skills, the type of paddling, and the boat. It is unrealistic to use any one person or any one boat as an example to support either a pro or con rudder argument. Conditions, paddlers, and boats are unique and even the same boat when improperly loaded will change its characteristics so much as to shift from the "don't need one" to the "do need one" category. (This has been, mentioned elsewhere but it bears repeating) There is no reason why boats can't be designed that do not need rudders. On the other hand there are reasons why it just isn't worth the effort to convince the buyer that he or she can handle the boat without one. >From a purely philosophical approach no system should be more complicated than it has to be. In the case of a sea kayak the basic premise is remarkably simple. The paddle/paddler provides both power and control. The need to portage and the nature of small creeks, lakes, and rivers forced natives to develop a craft that did not need a rudder and so canoes are often both adequately manoeuvrable and adequately directionally stable while paddlers learn to control their boats because there is no option. Modern sea kayaks, not faced with portaging and shallow water problems, adopted the rudder as a substitute for skills and/or to compensate for certain design characteristics. If there had been some physical reason why a rudder would have been undesirable then sea kayaks would have been designed to be paddled without and this issue would never have surfaced just as it has not surfaced as a serious issue for white water kayaks. It is worth noting that some Inuit adopted crude rudders on directionally unstable boats once they saw European ships and boats with them. It is difficult to tell if the boats got directionally unstable after the rudder became available or if the rudder came along later and was used to cure a long standing design flaw. Not sure this helps anyone. if you are interested in how and why boats turn you can read my page on the topic at http://home.ican.net/~735769/control.htm It is non-commercial so there is no sales pitch on the page. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>There are boats that are designed in such a way that a paddler can easily >learn to handle the boat without a rudder. > The primary purpose of a rudder is as an ENERGY SAVING DEVICE. It is not to help handling or turning, etc. I have had both ruddered and unruddered boats. If you are traveling long distance in windy, choppy conditions a rudder saves energy. No matter how skilled you are. Jerry *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Gerald Foodman wrote: > ...SNIP... If you are traveling long distance in windy, choppy conditions a > rudder saves energy. No matter how skilled you are. While this may be your experience, and while it is definitely true for some boats, I do not believe that it holds as a general proposition. >From the standpoint of energy use, a rudder has both an advantage and a disadvantage. The advantage is that one avoids the energy loss associated with corrective strokes (or edging). The disadvantage is that the rudder adds significant drag. If you are paddling a boat that you have to fight to keep on course when not using the rudder (such as a surf ski), then the rudder's energy-saving advantage outweighs the disadvantage of increased drag. But for boats that require little effort to keep on course, the drag of the rudder probably outweighs any energy saving from being able to avoid occassional corrections. (I say probably because I am unaware of any scientific tests.) One of my boats has a rudder. It seems to me that this boat (a Solstice) requires less effort to paddle in windy conditions when the rudder is retracted. This is a boat that is very easy to hold on line without using the rudder. If you have a boat that is difficult to handle without the rudder, then the use of a rudder with such a boat probably does save energy when paddling in the wind. But I have seen no evidence to suggest that this is generally true, and I have anecdotal evidence to the contrary. Dan Hagen Bellingham, Washington *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Jerry wrote; >The primary purpose of a rudder is as an ENERGY SAVING DEVICE. It is not to >help handling or turning, etc. I have had both ruddered and unruddered >boats. If you are traveling long distance in windy, choppy conditions a >rudder saves energy. No matter how skilled you are. This may be the case in boats that are difficult to control and have strong weathercocking tendencies. It is not the case in those boats that track well without need for a rudder. In fact, tank testing has shown that rudders add a much a ten percent to overall drag. While this high figure maybe due to the rather poor design of most rudders it still is an indication of the cons of a rudder. I think it is important to understand that not all boats weathercock badly or lack controllability and that not all boats require special skills to keep them on course. One must not assume that, because most of the boats one has paddled lack controllability that all boats lack controllability. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
For relevance, what percentage of a "good paddler's" energy goes into maintaining direction? It would seem to be over 10% for most paddlers under most conditions. The test for the 10% could also have significant variance. If the 10% was measured with the rudder dead center and the boat pulled straight, the drag would be significantly different when being used to correct for crosswind/current. ><clip> In fact, tank testing has shown that >rudders add a much a ten percent to overall drag. While this high figure >maybe due to the rather poor design of most rudders it still is an >indication of the cons of a rudder. > >I think it is important to understand that not all boats weathercock badly >or lack controllability and that not all boats require special skills to >keep them on course. One must not assume that, because most of the boats >one has paddled lack controllability that all boats lack controllability. > >Cheers, >John Winters >Redwing Designs >Specialists in Human Powered Watercraft >http://home.ican.net/~735769/ > > > >*************************************************************************** >PaddleWise Paddling Mailing List >Submissions: paddlewise_at_lists.intelenet.net >Subscriptions: paddlewise-request_at_lists.intelenet.net >Website: http://www.gasp-seakayak.net/paddlewise/ >*************************************************************************** > ,,, (o o) ==================oOO--(_)--OOo========================== Bob Washburn whiterabbit_at_iw.edwpub.com or rwashbu_at_siue.edu "Are on the cutting edge or the lunatic fringe?" ========================================================= *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Bob Washburn wrote: > > For relevance, what percentage of a "good paddler's" energy goes into > maintaining direction? It would seem to be over 10% for most paddlers > under most conditions. This is an excellent question. In my experience, however, it seems as though it is more like 3 to 5 percent--certainly far less than 10 percent. But this is based on a subjective judgement, and it is very much dependent on the boat being paddled. I will be able to do somewhat more objective measurements once I get my Differential GPS system operational. (Is that John I hear groaning?) DGPS allows very precise measurements of speed. I can try to maintain constant effort with and without a rudder deployed in windy conditions, and measure the difference in speed. I would hypothesize that I will make better speed without the rudder. Of course the results could always be challenged on the grounds that I receive a psychological boost by paddling without the rudder. It is exceedingly difficult to run a test of this type with "airtight" controls. > The test for the 10% could also have significant variance. If the 10% > was measured with the rudder dead center and the boat pulled straight, the > drag would be significantly different when being used to correct for > crosswind/current. I agree. I would guess that the typical flat-slab rudder adds more than 10% drag when held at an angle. BTW, where are the aeronautical engineers when you need them? Didn't George Gronseth help to design the rudder for the Boeing 767? I'm sure that he has something to say on this subject. (BIG grin.) Dan Hagen Bellingham, Washington *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
-> >This may be the case in boats that are difficult to control and have strong >weathercocking tendencies. It is not the case in those boats that track >well without need for a rudder. In fact, tank testing has shown that >rudders add a much a ten percent to overall drag. While this high figure >maybe due to the rather poor design of most rudders it still is an >indication of the cons of a rudder. > >I think it is important to understand that not all boats weathercock badly >or lack controllability and that not all boats require special skills to >keep them on course. One must not assume that, because most of the boats >one has paddled lack controllability that all boats lack controllability. > >Cheers, >John Winters >Redwing Designs >Specialists in Human Powered Watercraft Like Dan Hagen in the previous message in this thread I have a Solstice. Mine is a GTS which indeed is a superb tracker without the rudder. I have no problems controlling direction in windy choppy water without the rudder. The boat is remarkably insensitive to the wind and does not need a rudder. Nevertheless, if I am just travelling, not playing, in these conditions, it is much more relaxing and less tiring to deploy the rudder. Any added drag is more than compensated by the non-necessity for any course corrections which would be necessitated more by the chop than the wind. In flat protected water, the added drag is noticeable and I generally raise the rudder, even in strong wind. How well do you think the tank tests represent boat behavior in wind and chop, with uneven paddle strokes? Jerry *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Bob wrote; >For relevance, what percentage of a "good paddler's" energy goes into >maintaining direction? It would seem to be over 10% for most paddlers >under most conditions. Wish I knew. This is a huge variable. There are no studies that I know of but it would be relatively easy to calcuate the loss in energy between a sweep and straight ahead stroke. What is more difficult are the biomechanical losses. The tank data showed what the drag was under ideal conditions i.e. no stall no surge, no heave, no sway, no yaw. It also only showed what happene with the rudder tested. There is a huge amount of data on the drag characteristics of airfouls that is directly applicable to boats. In fact it is regularly used to design boats, particularly keels and rudders for sail boats. The difference between foils is easily calculated as is the stall angle. Our good friends in the aircraft business have done all the hard work. No question that an properly shaped airfoil ruder would be an improvement over the common flat plate. Dan wrote; >This is an excellent question. In my experience, however, it seems as >though it is more like 3 to 5 percent--certainly far less than 10 >percent. But this is based on a subjective judgement, and it is very >much dependent on the boat being paddled. I will be able to do somewhat >more objective measurements once I get my Differential GPS system >operational. (Is that John I hear groaning?) DGPS allows very precise >measurements of speed. I can try to maintain constant effort with and >without a rudder deployed in windy conditions, and measure the >difference in speed. I would hypothesize that I will make better speed >without the rudder. Of course the results could always be challenged on >the grounds that I receive a psychological boost by paddling without the >rudder. It is exceedingly difficult to run a test of this type with >"airtight" controls. This should be an interesting test. My experience is that I cannot maintain a uniform power output. Certainly not uniform enough to say that I can personally sense or measure small differences in resistance. Anyone who can has a great future career as a test device. Test tanks using the most sensitive measurement devices available (the Navy spares nothing in its quest for speed) don't claim better than +/- 5% so a person who can do better is going to be able to name his own price. Nevertheless, such a test would be useful. For instance, if you ran a base series of tests in calm, wind free conditions to establish a norm and then ran tests in windy conditions at different angles to the wind you will be able to get a good idea of leeway and drag effects. It would not be necessary to have precise speed effects but only velocity made good in the desired direction. This is something I don't think has been examined. Not sure how you would control heading with accuracy. I think the problem with trying to isolate rudder drag in these conditions is that one may have trouble quantifying the true effect. For instance, when paddling I rarely try to hold tightly to course. My boat wanders from side to side with waves and the wind. I focus on the distant objective and am only concerned with the end product. In other words, my feedback loop has a lot of slop an delay. The tendency with a rudder may be to decrease the delay and might actually make the rudder look worse than it is. If one is constantly wiggling the rudder to keep precisely on course the drag will naturally increase. I suspect that beginners are the worst for this and think it is sign of seamanship to steer a perfectly straight line. Marathon racing canoes use the sit-and-switch paddling technique which, although the boat wanders about the mean course the end result is more efficient than trying to adhere rigidly to the course with steering strokes. Another interesting test would be to have skilled and unskilled paddlers do the same series. It may reveal the relative importance of skill development in efficient paddling. Maybe tests with beginners and then repeated tests as they improved. Jerry wrote; >Nevertheless, if I am just travelling, not playing, in these conditions, it >is much more relaxing and less tiring to deploy the rudder. Any added drag >is more than compensated by the non-necessity for any course corrections >which would be necessitated more by the chop than the wind. In flat >protected water, the added drag is noticeable and I generally raise the >rudder, even in strong wind. This is something that Dan's tests might shed some light on. It may appear that one is working less but one doesn't really know what the net result. Subjective evaluations are a mixed bag. Sometimes they are pretty good and sometimes they are terrible. The problem is that you never know which until some one does a quantitative evaluation. > >How well do you think the tank tests represent boat behaviour in wind and >chop, with uneven paddle strokes? Tank data is one part of the equation. The resistance will not get better because of rough water, etc.. and will probably get worse. The net effort (effective horsepower consumed) may get better or it may get worse. One just doesn't know for certain. For example. A while back Sea Kayaker published an article about a couple who got into trouble. The male half said that at one point the boat wouldn't turn even though the rudder was hard over. Why not? The answer is rather simple. They were making very little speed and the rudder was stalled. the result was the rudder lost its turning effectiveness and, because it was now stalled it was slowing the boat even more and they were making more leeway and thus getting more weathercocking. The closed loop just kept getting worse. Sailors known that, when the rudder stalls you straighten it out to reattach the flow. Novice paddlers don't know this and just keep making the problem worse. Some of us may have experienced situations in heavy cross winds when the boat was weathercocking and the harder we paddle on the windward side the more the boat wanted to turn into the wind. It seems like a paradox until one understands that it is leeway combined with velocity that causes the turning moment and that the corrective turning moment is only working for us while the paddle is in the water. During recovery the combined velocity and leeway cause the boat to turn back to weather. Very frustrating and it is times like that when a rudder, retractable skeg or a different boat is much desired. Michael wrote; >The goal of racing is to win the race. >Kayak camping/cruising is almost by definition, steping out of the 'race' >alltogether This is quite true but human nature being what it is one is always trying to go faster or improve efficiency. There is, however, a practical reason for more efficient boats and that is safety. If you are trying to avoid being blown onto a rocky lee shore you will want a boat that can do it. A water pig may be just fine when conditions are benign but could be dangerous when the going gets tough. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: > ... Test tanks using the most > sensitive measurement devices available (the Navy spares nothing in its > quest for speed) don't claim better than +/- 5% so a person who can do > better is going to be able to name his own price. ... I'm not sure what that "+/- 5%" refers to, but if it is the error associated with a single test, and if the error is random, then I would think that averaging the results from repeated tests would improve the accuracy substantially. In any event, it is relatively easy to test for repeatability. There were some results of on-the-water tests posted to rec.boats.paddle a while back in which a paddler tested various kayaks in flat water along a measured course of one nautical mile. He tested the boats at "maximum effort" and at "90% effort" (which he describes in some detail). He claims that for his base boat (a Mariner II) at maximum effort, his times from different runs are separated by about .02 knots (!), which is less than one percent. At 90% effort he claims that repeated runs are within .05 knots (which is about one percent). These results are NOT based on averaging, but are the absolute differences between individual runs. (Maybe he should apply to the Navy for a grant.) I am quite confident that I would do less well in terms of repeatability between individual runs (especially in windy conditions), but I would expect that averaging the resulting rudder/nonrudder ratio from numerous repetitions would significantly improve the reliability of the results. John continues: > I think the problem with trying to isolate rudder drag in these conditions > is that one may have trouble quantifying the true effect. For instance, > when paddling I rarely try to hold tightly to course. My boat wanders from > side to side with waves and the wind. ... This is a very important point. Trying to hold a boat on a rigid course is inefficient. This introduces another variable into the test. A paddler who uses the rudder efficiently may get better results than someone who is trying to hold an overly rigid course, and so the results obtained for one paddler might not be generalizable to others. The same is true, of course, for the tests obtained without the rudder. Some use a more efficient technique than others when paddling without a rudder. The use of a rudder might increase total effort for some, while reducing it for others. So even if this can be answered for a given paddler (which is far from certain), others may question with justification whether the results apply to them. The bottom line is that such tests are probably not worth the effort. Dan Hagen Bellingham, Washington *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
735769_at_ican.net wrote: > Michael wrote; > > >The goal of racing is to win the race. > >Kayak camping/cruising is almost by definition, steping out of the 'race' > >alltogether > > This is quite true but human nature being what it is one is always trying > to go faster or improve efficiency. There is, however, a practical reason > for more efficient boats and that is safety. If you are trying to avoid > being blown onto a rocky lee shore you will want a boat that can do it. A > water pig may be just fine when conditions are benign but could be > dangerous when the going gets tough. The big danger is to assume that the boat/paddle that is most efficient with a high power paddler at 6+ knots is also going to be more efficient with a casual paddler at 3- knots. A fairly short boat with fine ends and low wetted surface that hits a wall at 4 knots might be a dream for a paddler who never goes over 3 knots, but would be a disaster for a racer who never drops below 5 knots. At the same time, the racing boat with more length, higher prismatic and more wetted surface, that wins races for the strong racer would actually slow the weaker paddler down. Even the boat that wins in waves and chop is not always going to be the one that wins in flat water. michael *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Dan wrote; re: tank test accuracy; >I'm not sure what that "+/- 5%" refers to, but if it is the error >associated with a single test, and if the error is random, then I would >think that averaging the results from repeated tests would improve the >accuracy substantially. (SNIP) No one tests a ship with just one run down the tank. It would be poor science and irresponsible professionally. The +/- 5% is based upon tens of thousands of tests in tanks around the world. When reading reports like the fellow in rec.boats.paddle one has to ask a simple question - Is the test repeatable by some one else. The answer is simple. NO. No one else can duplicate the test. You can't duplicate the conditions his mental attitude, his physical status, his prejudices and bias (show me a person without them) etc.. ad nauseum etc.. More importantly, the paddler was testing at maximum output when the resistance curve is climbing at a steep angle. Thus, any increase in power would have minimal effect on speed. Where power output varies most is at the cruising rate where most of us paddle and what most of us are interested in. A fundamental of science is that every theory and experiment carries with it test that a will prove the theory or experiment wrong. Demonstrating the flaws in his method is easy. > >. The bottom line is that such tests >are probably not worth the effort. They might be useful to you, however. For instance, suppose you found that you could tolerate considerably more yaw than you normally do (or the opposite). Might change the way you paddle in rough water. Andy Knapp's experience is a good example of a test that establishes a rational need for a rudder in his case but would be unreliable in establishing a rational need for a rudder in another person's (or boat's) case. Andy's methodical method, (even if a bit flawed from a scientific standpoint) is exactly what most paddles should do to satisfy themselves that they are getting what they think they are getting in their boats, paddles, and equipment (if you care that is). Just to provide some perspective, every boat that I design (and those of some competitors) is tested using a Brooks and Gatehouse Speed Boss. All tests are done by me using the same paddle on the same body of water in calm conditions. Each test series involves over 100 runs. 50% are done at cruising power (for me) and 50 % done at gradually increasing power output. Suffice to say and without boring you with reams of data. I don't get nearly the repeatability that others get in their tests. No doubt this is because I am not so good a paddler but I suspect that I am closer to the norm than the experts. I have tried some expert paddlers but have not yet found one a whole lot better. Perhaps it is just more difficult to get accurate results when the tests are controlled. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: > No one tests a ship with just one run down the tank. It would be poor > science and irresponsible professionally. The +/- 5% is based upon tens of > thousands of tests in tanks around the world. [snip] > Just to provide some perspective, every boat that I design (and those of > some competitors) is tested using a Brooks and Gatehouse Speed Boss. [To John: What is that? What does it measure?] > All tests are done by me using the same paddle on the same body of water in > calm conditions. Each test series involves over 100 runs. 50% are done at > cruising power (for me) and 50 % done at gradually increasing power output. > Suffice to say and without boring you with reams of data. I don't get > nearly the repeatability that others get in their tests. No doubt this is > because I am not so good a paddler but I suspect that I am closer to the > norm than the experts. I have tried some expert paddlers but have not yet > found one a whole lot better. Perhaps it is just more difficult to get > accurate results when the tests are controlled. John, it has occurred to me that perhaps an improved (or, maybe, just alternate) way to gather data on the paddler/paddle/boat system is to place a force sensor *between the paddler's hands and the paddle shaft* and an inertial displacement sensor *on the paddle shaft* at the hand position. These, coupled with a knotmeter, and with real-time data piped to some on-board data-gathering instruments, might allow each paddler to tune his/her stroke style and paddle choice to achieve a more objective estimate of what works best. The on-board data-gathering stuff could be as simple and cheap as the system I use extensively with my students (they are TI Calculator Based Laboratory units, interfaced with a graphing calculator). The force sensor I suspect could be cobbled together from thin pressure-sensing pads which could be made to conform to the shape of the paddle. Don't know about the inertial displacement sensors. Of course, knotmeters are off-the-shelf. Reason this came to mind is that it is *peak force* which is the prime determinant in exacerbating tendonitis, while it is some rude analog to "force times distance" that determines how much energy the paddler puts into the water. As one susceptible to tendonitis, I could really use an analysis which could allow me to "spread out" the force I exert on the paddle, while retaining the same total energy (work) expended on the paddle/boat system. Do you (or, others) have any knowledge of Olympic racers (or, similar) who might have developed such a system? Thanks. -- Dave Kruger Astoria, OR paddler/chemist/teacher *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Dave wrote; > >> Just to provide some perspective, every boat that I design (and those of >> some competitors) is tested using a Brooks and Gatehouse Speed Boss. > >[To John: What is that? What does it measure?] The B&G Speed boss measures speed, acceleration with each stroke and speed loss during recovery, distance through the water, max and min speeds during a run, strokes, times rest periods,stores up to 100 runs for download to a computer for analysis and brews coffee when you are done. (SNIP including discussion of measuring forces at the paddle) ) . > >John, it has occurred to me that perhaps an improved (or, maybe, just >alternate) way to gather data on the paddler/paddle/boat system is to >place a force sensor *between the paddler's hands and the paddle shaft* >and an inertial displacement sensor *on the paddle shaft* at the hand >position. (SNIP) This method tells you how much force was applied to the paddle but not how much of the force was effectively transferred to the boat. For instance, a brace might record as much force as a forward stroke but doesn't drive the boat ahead. A poor paddler might use a lot more energy than a good one for the same speed. This is useful knowledge for paddler training but not so useful for boat design. >Do you (or, others) have any knowledge of Olympic racers (or, similar) >who might have developed such a system? I have tinkered with an idea for a seat mounted on sensors that would measure the forces and direction of forces applied to the boat but it is on the back burner. About a year ago a fellow said he was developing a system similar to what you suggest but he never came up with anything. Matt Brose also was thinking about this but didn't have time to develop it. Joy wrote; >But I find myself wondering whether simply some >people's bodies are more comfortable going along in a higher gear to accomplish the >same speed or distance that others would comfortably do in lower gear. I have >always biked in high gears (not up mountains, I should say, mostly just around town) >and find that downshifting is a more strenuous way to cover distance. (Also much >less fun.) Many years ago I looked into this and it does seem that every person has a "natural cadence" that is most comfortable. Possibly due to body mass etc.. No doubt you can train to change it but I wonder if it is not simpler just to fit the paddle to your natural cadence rather than trying to change your cadence to fit your paddle. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Tue, 31 Mar 1998, John Winters wrote: > The B&G Speed boss measures.... Cool, how heavy, and how much do they cost? Is it riggable so it doesn't interfere with paddling a tandem canoe or sea kayak? *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>Joy wrote; > >>But I find myself wondering whether simply some >>people's bodies are more comfortable going along in a higher gear to >accomplish the >>same speed or distance that others would comfortably do in lower gear. I >have >>always biked in high gears (not up mountains, I should say, mostly just >around town) >>and find that downshifting is a more strenuous way to cover distance. >(Also much >>less fun.) > > >Many years ago I looked into this and it does seem that every person has a >"natural cadence" that is most comfortable. Possibly due to body mass etc.. >No doubt you can train to change it but I wonder if it is not simpler just >to fit the paddle to your natural cadence rather than trying to change your >cadence to fit your paddle. > >Cheers, >John Winters I think John is absolutely right on this, but I think if you were trying to become a stronger paddler, and really wanted to train hard to get their, you may want to add specific energy system training to your paddling workouts, ala Greg LeMond......One day a week use a larger bladed paddle for doing sprints---this training your ATP system and anaerobic power.One to three days a week do aerobic paddling, using a small paddle with very high turnover. One day per week do a race simulation ( anaerobic hreshold ---maximum speed you can sustain for close to an hour without your torso tuning to jello and nausea levels shutting you down) on a real course, probably with the smaller paddle, unless you want to spring for a medium blade. In this manner you could train all three energy systems, and be better able to handle all the conditions in a race or weather induced risky environment ( I'm sure many have experienced storm situations where you have to paddle fairly hard to maintain course and stable speed, with occasional bouts of "panic speed", when monster rogue waves head toward you, or some other temporary threat---this is the reason for the ATP system, and anaerobic system training---which, if you were really serious, would be broken down still further into one day with 10 second sprints, and another day with 60 second sprints, with 4 minute rests with continued moderate speed paddling during the recovery time of 4 minutes. ). Of course, with all these different paddles, this could get even more expensive than cycling :-)......John, this could be a marketing opportunity :-) Regards, Dan Volker WPB,Fl *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>I think John is absolutely right on this, but I think if you were trying to >become a stronger paddler, and really wanted to train hard to get their, you >may want to add specific energy system training to your paddling workouts, >ala Greg LeMond......One day a week use a larger bladed paddle for doing >sprints---this training your ATP system and anaerobic power.One to three >days a week do aerobic paddling, using a small paddle with very high >turnover. But a key point is that the large paddle stroke, eg., Greg Barton's, is totally different than the narrow blade stroke, eg., Van Doren's Greenland style. This is different than for bikes where there is no difference in stroke for different gears. So the overall efficiency depends both on paddle design and using the proper technique for that paddle. Jerry *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Kirk wrote; : > >> The B&G Speed boss measures.... > >Cool, how heavy, and how much do they cost? > >Is it riggable so it doesn't interfere with paddling a tandem canoe >or sea kayak? Weighs about a pound and costs about $800 U.S. Unfortunately it isn't very practical for cruising as the stroke counter has to be attached to your paddle all the time. Worse than a tether.:-) Also the impeller is mounted on the bottom and if it is in the proper spot it is vulnerable. If you are still interested I will send the address of the manufacturer. Jerry wrote; >But a key point is that the large paddle stroke, eg., Greg Barton's, is >totally different than the narrow blade stroke, eg., Van Doren's Greenland >style. This is different than for bikes where there is no difference in >stroke for different gears. So the overall efficiency depends both on >paddle design and using the proper technique for that paddle. I don't know that anyone has done much with small blades and a more vertical stroke. Always it seems to be small blades on long shafts (Greenland) or large blades on short shafts (racing and white water) . This is not really a fair comparison. From a purely mechanical standpoint, the stroke closer to the boat wastes less energy (less wasted on turning moment). From a purely biomechanical standpoint the more vertical stroke promotes more body rotation and use of torso muscles while making best use of the arms for maximum push and pull. It would seem to me that one might get best results using a small blade that did not stress muscles an a short paddle with a more upright stroke for greatest efficiency. The Greenland style of stroke may be a product of its length and poor physics. It may work because of the blade size and nothing else. This fits with what Jerry is saying - adjust the stroke to suit the paddle. The big question is, does the stroke control paddle choice or does the paddle choice control stroke? Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: > I don't know that anyone has done much with small blades and a more > vertical stroke. Always it seems to be small blades on long shafts > (Greenland) or large blades on short shafts (racing and white water) . This > is not really a fair comparison. From a purely mechanical standpoint, the > stroke closer to the boat wastes less energy (less wasted on turning > moment). From a purely biomechanical standpoint the more vertical stroke > promotes more body rotation and use of torso muscles while making best use > of the arms for maximum push and pull. > > It would seem to me that one might get best results using a small blade > that did not stress muscles an a short paddle with a more upright stroke > for greatest efficiency. John, I agree with this analysis. The problem is where do you find such paddles. Everything I have seen is short with wide blades, or long with narrow blades. I can't find any paddles with a short shaft and narrow blades. Any suggestions? Richard Fawcett Mayberry, NC > Cheers, > John Winters > Redwing Designs > Specialists in Human Powered Watercraft > http://home.ican.net/~735769/ > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
how 'bout a 6' storm paddle? Fred Richard Fawcett wrote: > John Winters wrote: > > > I don't know that anyone has done much with small blades and a more > > vertical stroke. Always it seems to be small blades on long shafts > > (Greenland) or large blades on short shafts (racing and white water) . This > > is not really a fair comparison. From a purely mechanical standpoint, the > > stroke closer to the boat wastes less energy (less wasted on turning > > moment). From a purely biomechanical standpoint the more vertical stroke > > promotes more body rotation and use of torso muscles while making best use > > of the arms for maximum push and pull. > > > > It would seem to me that one might get best results using a small blade > > that did not stress muscles an a short paddle with a more upright stroke > > for greatest efficiency. > > John, I agree with this analysis. The problem is where do you find such > paddles. Everything I have seen is short with wide blades, or long with narrow > blades. I can't find any paddles with a short shaft and narrow blades. Any > suggestions? > > Richard Fawcett > Mayberry, NC > > > Cheers, > > John Winters > > Redwing Designs > > Specialists in Human Powered Watercraft > > http://home.ican.net/~735769/ > > > > *************************************************************************** > > PaddleWise Paddling Mailing List > > Submissions: paddlewise_at_lists.intelenet.net > > Subscriptions: paddlewise-request_at_lists.intelenet.net > > Website: http://www.gasp-seakayak.net/paddlewise/ > > *************************************************************************** > > ------------------------------------------------------------------------ > > Richard Fawcett <mayberryrf_at_advi.net> > Attorney > > Richard Fawcett > Attorney <mayberryrf_at_advi.net> > 603 North Main Street Work: 336-789-4179 > Mount Airy Fax: 336-789-4171 > NC Home: 336-789-2042 > 27030 Netscape Conference Address > USA Netscape Conference DLS Server > Additional Information: > Last Name Fawcett > First Name Richard > Version 2.1 *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: [snip] >The big question is, does the stroke control paddle choice >or does the paddle choice control stroke? > To a large extent, if we will let it, paddle choice can control stroke. A lot of work has shown that animals automatically shift gaits to whatever is most efficient at the desired speed (when maximum speed is not necessary), and I think we've all noticed how difficult it is to walk very fast without at least a few running steps. Of course paddling isn't as natural as walking/running (no flames please!) so the appropriate changes don't force themselves upon us. One time I temporarily switched paddles with someone who had a much longer paddle than mine, with an equally large blade, and I found that besides slowing down my stroke I needed to shift to a sliding more-or-less-Greenland-type stroke to be comfortable with the long paddle. Clearly a novice paddler won't know how to find a better stroke for a given paddle, but experienced paddlers should, if they pay attention to how the paddle-body combination is working, be able to shift to something appropriate. I apologize for how wooly this sounds. Bruce Winterbon bwinterb_at_intranet.ca http://intranet.ca:80/~bwinterb All states have laws to protect the rich from the poor. Few attempt the more difficult task of protecting the poor from the rich. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Richard wrote (SNIP) >John, I agree with this analysis. The problem is where do you find such >paddles. Everything I have seen is short with wide blades, or long with narrow >blades. I can't find any paddles with a short shaft and narrow blades. Any >suggestions? > Changing the size of an existing blade is not difficult. One could buy a standard glass blade and then start cutting it down in increments until it felt just right and I would think. Maybe Hank Hays can comment on this. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: > > Richard wrote > (SNIP) > > >John, I agree with this analysis. The problem is where do you find such > >paddles. Everything I have seen is short with wide blades, or long with > narrow > >blades. I can't find any paddles with a short shaft and narrow blades. > Any > >suggestions? > > > Changing the size of an existing blade is not difficult. One could buy a > standard glass blade and then start cutting it down in increments until it > felt just right and I would think. Maybe Hank Hays can comment on this. > > Cheers, > John Winters It can absolutely be done. Years ago a friend of mine had a Werner San Juan with which he wasn't happy because of the size of the blade. He cut it down to a size and shape he liked. That next year Werner itself came out with the Camano which was millimeter for millimeter identical to what he had made for himself, a case of good minds thinking alike. ralph -- ----------------------------------------------------------------------- Ralph Diaz . . . Folding Kayaker newsletter PO Box 0754, New York, NY 10024 Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com "Where's your sea kayak?"----"It's in the bag." ----------------------------------------------------------------------- *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John Winters wrote: > ...SNIP... > Andy Knapp's experience is a good example of a test that establishes a > rational need for a rudder in his case but would be unreliable in > establishing a rational need for a rudder in another person's (or boat's) > case. ... I agree with this, but I suspect that some folks might be inclined to overgeneralize from his results. In certain conditions there are some boats that are paddled more efficiently by using a rudder. I would also suggest, however, that there are some boats that --for some paddlers--are paddled more efficiently without the use of a rudder (even in windy conditions). I would hope that everyone understands that demonstrating the first proposition does not disprove the second. Finally, I would suggest that there are some folks (such as myself) who simply *enjoy* paddling without a rudder, regardless of the implications for efficiency (while acknowledging that there are others who feel differently, and who get more enjoyment by using a rudder at times). I guess this makes me one of those anti-rudder religious purists. Happy paddling! Dan Hagen Bellingham, Washington *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Michael wrote; (SNIP) (SNIP) >The big danger is to assume that the boat/paddle that is most efficient >with >a high power paddler at 6+ knots is also going to be more efficient with a >casual paddler at 3- knots. > (SNIP) This quiet true. The problem stems from a fundamental problem with the word "speed". When most people talk about "speed" what they really mean is efficiency at their power output. They know they will never paddle a fast as a sprint racer but they still want to go as fast as they can when cruising. Thus, a boat that allows them to go faster at their normal cruising speed is "fast". That same boat may not be "fast" for some one else. This is why graphs of resistance are so important. Strong paddlers will want boats with high prismatic coefficients and greater length to make best use of their power. Smaller less strong paddlers will want shorter boats with low prismatic coefficients to provide low resistance at cruising speeds. A boat that is "fast" for the one type of paddler will not be "fast" for the other. This difference (and others like displacement, paddling style, etc..) is why two paddlers will have different opinions of the same boat and why people should be cautious when accepting a recommendation for boat from some one else. I always pucker up a bit when people ask what boat others recommend (particularly on the Internet). not only does the person asking the question not know anything about the respondent but the respondent knows nothing about the questioner. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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