change your partner’s paddle, not yours
""""“Currently I use an Epic small wing at 217 cm. He uses a Werner Euro style, low angle paddle at 230 cm.”""""
Your partner is likely not getting the most efficient use of his HR with that long paddle. And you probably don’t need more surface area at the speeds you’ll be doing for that distance. If you’re rate is way too high then it isn’t likely the paddle at the speeds you’re going in ultra distances. I paddle at a lower cadence and higher speed now with a 215 mid wing than I did a few years ago with a 219 large.
Maybe Carldelo’s expiriments will prove me wrong. but my experience is that you guys will benefit from paddling in sync with a similar style. The only way I can conceive that paddling out of sync could be easier/more efficient at a given speed than paddling in sync is if the in-sync cadence is so slow that the boat has time to decelerate substantially to a speed at which the drag matches the force of an individual’s stroke. That would be below what I would even consider cruising pace. In everything I’ve paddled from sit down C2 to k4 and OC-6, racing or cruising, in-sync gets higher boat speed at a lower HR and less pressure per stroke.
Surely someone can take drag numbers on various hulls and compare it to continuous force application (idealized out-of-sync power application) at the power of one person and then compare that to the averaged power output of a pair paddling in sync. I think that force curves for the stroke are out there.
shoot, last year
Shoot, last year the first two weeks of October were the hottest of the entire summer with dewpoints around 80F. It was brutal trying to prep for the Mayor’s Cup. This year June-August was the hottest on record with way below average rain but way higher than normal surface dewpoints. Lake Beresford was average 90-95F most days, hotter than the air temp. I wanted to be anywhere but here. This year the weather started to break about the time of the Paddle Battle; that was a fairly nice morning. It really broke this weekend. It was 58F at my house this morning. Absolute paradise. Fishermen were bundled up like it was snowing and I was shirtless and steaming and loving every minute of it. I’m not even really training right now, just paddling for the hell of it. Yesterday morning I paddled a few miles up past Blue Spring, then I cut through the canal at marker 80 to Hontoon Dead River and paddled back down into the St. Johns and then north a few miles and then home, I would have kept going but I got hungry and wanted to take the canoe to explore a little lake over in the forest.
While all are exhausted
from the discussion, paddles are not necessarily the same as gears on a bike as I once thought. A larger paddle blade helps accelerate faster, but has a small improvement in short term top speed. Once the boat is at its fast cruising speed and the paddle is no longer slipping in the water with each stroke, the blade size doesn’t matter. Hence, trying to match paddle strokes (going toward in synch) at a ratio of 3:2 using blade size just will not work. Can you compromise on a 60 count stroke rate, and maybe work up to 65, a good cruise stroke rate for most long distances?
Spinning the tires . . .
A lot of the argument for out of synch paddling has mentioned reducing the length of the deceleration phase as a goal Let’s keep in mind that when paddling in synch, even at 60 strokes per minute, the time between strokes (deceleration phase) is very short, probably less than 0.25 second. I do believe that paddling out of synch could flatten out the tops and bottoms of the w's in the speed graph, but I also believe that the overall speed would be less and that the work done by the two paddlers would be more than if two paddlers were paddling in-synch at the same speed. (This may not hold true if the strokes per minute fell below 60 or the speed fell below 3 knots, or maybe if you were paddling a fully loaded tandem upwind, but that is not really the subject of this discussion).
Many of the arguments in the thread above would hold (or at least be more apt) if paddling was more like cross country skiing, where the pole is planted in a a fixed place in the snow. If this were the scenario, I agree that out of synch might be just as effective. However, as several have stated above, this model fails in the sense that it ignores the fact that we do after all plant our paddles in a fluid medium.
When we plant a paddle for the catch, there are two possible outcomes: (1) the boat moves forward; (2) the water moves "backward*"
Imagine sitting in your kayak on a low dock and executing a forward stroke. The kayak may slide forward an inch or two, if at all. Meanwhile, a few gallons of water gets pushed backward. If the resistance of the hull is disproportionate to the surface area of the paddle blade, the kayak will not move -- or will not move very much, but the water will. The kayak moves forward only to the extent that the friction of the hull is less than the grippiness (or friction) of the paddle.
Paddling, then, is about minimizing hull friction and maximizing paddle friction (or grip) on the water. However there is no perfect paddle stroke. Even a wing blade does not stick, unmoving in the water, as if in cement.
Summarizing from the thread above and from my own logic, here are a few more principles that seem important:
--Since a single paddle stroke is more an uneven pulse than a steady draw, paddling at "constant speed" requires a repeated acceleration of the hull during the active part of the stroke. Even when a tandem is paddled out of synch, in order to maintain speed, the power phase of each stroke must at least slightly accelerate the boat.
--the only way to accelerate the boat is to pull the paddle on its path from the feet to the hips at a rate that is faster than the present speed of the boat. This stroke can be executed more quickly and with less effort if the other paddler in a tandem executes a stroke at exactly the same time.
--Accelerating the boat (i.e. taking a paddle stroke) increases the friction (resistance) of the hull.
Doesn’t it make sense that whenever possible, the hard work of this “energy intensive phase,” accelerating the boat, which takes place primarily in the first fraction of a second following the catch, should be shared among two paddlers?
My theory goes like this: when paddling a tandem using a synchronized stroke, the “grippiness” or friction of the two blades is combined, resulting in more leverage on the water, making it easier for paddle friction to overwhelm hull friction and accelerate the boat.
Importantly, and I'm not sure anyone has said this yet, the inevitable amount of slippage (or wasted effort / “water pushing”) is also shared between the two paddlers, whose blades each “slip” only half as much as they would if taking a solo stroke. This means less total energy is wasted pushing water and more total energy is available to actually propel the boat.
I'll end with a question: if you are the stern paddler and paddling exactly out of synch, are you now planting your paddle in the "paddle wash" of the bow paddler. And, if so, does this affect the power of your own stroke?
(My major was English, guys, so go easy on me!
;-)
*"backward" is a simplification here, I realize.
pretty good for an English major
I think that’s a good conceptual summary. Better than I’ve done in the thread.
Sounds pretty good, …
... but I'll just quibble on the details. To say that paddles applied out-of-sync would slip twice as much can't possibly be correct, as I see it, unless the boat were going twice as slow when out-of-sync as when in-sync, AND if the speed of every paddle stroke remained constant with the boat being the frame of reference. Neither of those things would occur. The boat might slow down some - I'm starting to believe that to be true even for cruising speeds - but not all the way down to one-half speed. Then, even if it DID slow down that much, the paddlers would each have to increase their paddling effort in exponential fashion to achieve the same paddle speed relative to the boat as before, which would be necessary in order for each of their paddles to slip twice as much in the water as before. Such exponential increase in effort might be possible in some cases, but not if their initial speed already was requiring substantial effort.
The thing that complicates the effect of all these factors is that there is never a linear relationship between boat speed and the paddling effort that causes it, or the drag resulting from it. Of course, I'm the first to admit that the mathematics involved in calculating such stuff is way over my head. That would take some pretty elaborate work with calculus, I'm sure. I may be pretty accepting of the whole idea as presented by Scombrid now, but I won't accept the idea that paddlers who are out of sync must work twice as hard or that they waste twice as much energy in a similar way as if each was getting zero help from his partner. The effect of the partner's help does not go all the way to zero once the paddles are out of synch.
Mayor’s Cup 2009
…yep, last year weather was a wicked one: you had to train in FL on the 90’s to race in the lows 40’s in NY. How in the world can you prepare your body for that!
This year paddle battle weather was excellent (loved the venue) wish I had a more competitive k-1 field…
I’ve done a bit of racing in a tandem
and one phenomenon I’ve noticed is that if you get out of sync the rear paddler often ends up inserting his blade into the vortex left by the forward paddler. This causes a “hitch” that is highly irritating and late in a race quite tiring.
Details
Doubling the amount of paddle slippage wouldn't necessarily slow the boat down to half it's original speed. For the sake of example, let's say that in the case of 2 paddlers paddling a tandem in synch, the loss of speed due to paddle slippage is 10%.
According to my theory, if the same two paddlers now paddle out of synch (at the same pace in terms of strokes per minute), their loss of speed due to paddle slippage would be doubled or 20%.
In a case based on an ideal ("no-slippage) speed of 8 mph, this would mean the real world in synch paddlers would have a speed of 7.2 miles per hour and the out of synch paddlers would have a speed of 6.4 mph.
Other factors do come into play and would have to be factored into any real-world calculations. Some of these factors might reduce the difference between in synch and out of synch, but overall I think that the additional leverage gained by having 2 blades in the water at the same time far outweighs any advantage of the more constant speed made possible by paddling out of synch.*
*This may not be true if paddling slower than 45 strokes per minute, as the deceleration between strokes would then be more pronounced.
Cause and Effect
I'll start out by saying that I may not be picturing this correctly, and what I said may not be correct, but your interpretation of what I said is not what I meant, so I'll try to clarify.
I'm not saying the twice as much slippage causes the boat to slow to one-half speed. I'm saying that boat speed must somehow be cut in half in order for twice as much slippage to occur at a given cadence. Since maintaining the same cadence would require both paddlers to move their paddles at the same distance and speed relative to the boat with every stroke, the only way to get twice as much slippage would be for the boat's speed to be one-half of the original speed, because ONLY by slowing the boat down by that amount would the speed of paddle movement relative to the water (that's the same as slippage) be doubled. By the same token, both paddlers could maintain the same cadence and speed of paddle motion while sitting on chairs in shallow water, and their slippage would be 100 percent to match their 100-percent loss of speed. Does that help to clear up what I was getting at?
Here's a real-world example of how to achieve twice as much paddle slippage without changing cadence. You are paddling along at 6 miles per hour. A big motorboat comes up behind your, and ties a line to the back of your boat, then immediately cuts its travel speed to 3 miles per hour. That means YOUR boat is now going half as fast, and if you keep paddling at exactly the same rate as before, you paddle, by definition, is slipping twice as much as before since it is only giving you half as much forward speed. Later when I get time, I'll do some vector addition using various "believable" amounts of initial slippage to see if this actually works out to be true.
Finally, I'll think about this later and see if I can work out what you are saying, but at the moment I do not understand how your logic applies to your explanation for the speed loss when switching from in-synch to out-of-synch in an ideal situation with no paddle slippage. Without slippage, there's no practical limit to the thrust you can produce at real-world boat speeds in relation to real-world amounts of drag (producing 20 or 30 pounds of thrust would be possible if the paddle didn't slip, and probably even more than that, but in real life we don't approach that amount). Also, what is twice as much slippage as ZERO? Something seems to be missing in the logic of that example.
water is rising . . . .
You wrote: "your interpretation of what I said is not what I meant."
I was hoping it was. That would have made the rest of this conversation easier;-) I may be getting in over my head here, but I do enjoy the mental gymnastics it is inducing. Thanks for your explanation though. I will read it a few more times and see if I can get my head around it.
You went on to say: "I'm saying that boat speed must somehow be cut in half in order for twice as much slippage to occur at a given cadence."
Is slippage totally a function of boat speed and paddle speed? Does blade surface area also factor in? (And blade shape? Think wing paddle). With two paddlers in synch, blade surface area available with each stroke is twice that of two paddlers out of synch.
If you could somehow propel a toy kayak with a regular size paddle, you would come close to reaching the "no slippage" goal, I would think, as leverage available would far out-proportion the resistance of the hull.
Does the example of a car spinning a single rear wheel and remaining motionless on an icy hill have any relevance? Once more than one tire is engaged (4-wheel drive is switched on) the car moves forward again. More surface area has provided more leverage and an exponential improvement in speed.
I appreciate your example of the motorboat and tow line. Another way to say it is that the motorboat is increasing the hull resistance experienced by the paddler, right? Would that be the similar effect to a situation where the other guy in a tandem stopped paddling? The guy who kept paddling would experience increased hull resistance (since it was no longer shared) and the boat would slow down.
When I mentioned an "ideal no slippage situation," I meant just that -- an ideal situation that would never exist in the real world. Since water is a fluid, paddle slippage will always occur. Paddle slippage is only one of the several limitations on boat speed though, right? Another important limitation being hull resistance, which although related to slippage, is also a separate factor in it's own right that would still occur even if our paddles stuck in the water as if in cement.
I have to back up!!! I was wrong!!!
I think your original logic is correct, at least to the extent of your initial explanation of what you percieve to be happening. I should know better than to start writing before the situation has become totally clear in my mind. I had a road trip to do for work and decided to write "right now", and a few minutes after I hit the road, not only did the situation become clear in my mind, but the vector addition became clear in my mind too, so there was no need to resort to pencil and paper to check it out.
Okay, here's the use of the logic of vectors to explain what I am thinking, which I think is also in agreement with what you said in your previous post.
I'll use a high-speed example to get some easily-workable numbers. Let's say that on every stroke, the paddler moves his paddle toward the rear of the boat at 7 miles per hour (relative to the boat), but that the paddle is slipping backwards through the water at 1 mile per hour. That means the boat is moving forward at 6 miles per hour. Now, IF the rate of paddle slippage were to double due to increased drag on the boat or due to less effective "grip" of the water during each paddle stroke, the paddle would be moving through the water at 2 miles per hour (that speed of slippage may not be as extreme as first reactions, mine included, would suggest. I'll comment on that issue later). In THIS case, with double the slippage, the boat is moving at 7 - 2 = 5 miles per hour. Therefore, in THIS case, doubling the rate of slippage is associated with a change of boat speed from 6 miles per hour to 5 miles per hour, and that's NOT a reduction to half the original speed. So I stand corrected. All sorts of other boat speeds and paddle-slippage speeds can be tried, often with a speed change that is proportionately less than this example, and providing double the slippage results in one-half the original boat speed only in certain particular cases, not as a general rule.
So, you were right. I was wrong. Maybe English majors have an edge over entomology majors when understanding things outside of their field, haha.
Actually, I really love the process of understanding how things work (it makes me a dandy mechanic and gizmo-builder), and I really think this whole in-synch versus out-of-synch thing will be much more complex than any of us can account for "in our heads". In a previous post, I explained what I think is a likely reason that speed loss due to exponentially-increasing drag wouldn't necessarily result in a slower boat if the effect of that drag were not as pronounced as the effect of inertia between strokes. Maybe there's another explanation for what is causing that too, but that one works for me right now. Likewise, I believe this whole topic of thrust when shared at discrete times versus when not shared at the same time between paddlers can't be intuitively figured out as "logically" as so many are trying to do. Let me go back to an example I briefly touched on in an earlier post to show what I mean.
I mentioned earlier that a long time ago, a friend and I were unable to row our little fishing boat as anywhere nearly as fast as it could go when pushed by an electric motor providing just 18 pounds of thrust. Knowing what I know now, that fishing boat was going a fair amount faster than its hull speed when powered by the electric motor, but when powered by oars it would not exceed hull speed no matter how hard we tried. Now, I'm still at my place of work and can't measure the dimensions of my oars, but I seem to recall that standard oars of many different lengths have a ratio of outboard to inboard length of about 3:1. If that's the case, it takes a pull of just 27 pounds on the handle of each oar to achieve 18 pounds of total thrust ([18/2]x3=27). I know for sure that with my feet braced, even back then as a skinny (well, more skinny than I am now) 20-year-old kid, I could easily pull a whole lot harder than that if I wanted to without undue strain. So why was the boat drastically slower when a thrust that had to be significantly greater than 18 pounds was applied by oars than by when 18 pounds of thrust was provided by an electric motor? Simply because oar strokes occur during a fairly small fraction of the overall travel time, while the motor provided its thrust 100-percent of the time so the boat was never "coasting". This observation should show that paddling out-of-synch will not require twice the thrust to be applied with every stroke, and that applying thrust during a greater proportion of the overall travel time can reduce the magnitude of thrust that is needed, in the absence of other confounding effects. Does that mean that paddling out-of-synch requires less thrust per stroke? Probably not (because of those confounding effects - we've been talking about some of them), but by the same token, it ALSO does not mean that the necessary thrust, and therefore slippage, must be doubled. Once again, I also believe that this explains why propelling a boat suddenly becomes immensely easier, at any speed, as soon as your partner picks up a paddle and starts helping, even if they are totally out-of-synch with you.
My bottom line "this time" is that even though I now believe Scombrid is giving us the straight scoop for all reasonable travel speeds, I don't believe that the difference in required force for paddling out-of-synch is related in a simple arithmatic way to the force required when paddling in-synch. I am certain that the difference in effort betwee the two paddling methods is related to a number of things that change in geometric or exponential fashion, and thus the difference can be (and I believe is) less than "plain and simple logic" can explain.
**********
Okay, now to address that speed-of-slippage issue I mentioned earlier. Is 2 miles per hour of slippage too much to be realistic? I don't think so if you are pushing hard, even with perfect technique. The thing is, the paddle stroke occurs for such a brief moment, and you scoot past the point of your paddle "plant" so quickly, that even 2 miles per hour of slippage would only result in a slippage of only a few inches. I'm sure most of us have been cruising along comfortably and then got a sudden jolt when the paddle contacted a submerged log or rock with the power face. If that contact is off-center, the resulting torque on the shaft is too much to resist even if you recognize that the impact might happen and you prepare yourself for it. When the paddle is not slipping very much (such as when you are lilly-dipping along), you don't experience such an impact of an object against the power face as when paddling hard. In fact, even when paddling hard while going downstream with a respectable current, the paddle often wacks a rock or log with its power face. That simply couldn't happen unless the slippage speed were faster than the current. If the paddle-slippage speed were 1 mile per hour and you paddled downstream with a current that moves 1 mile per hour or faster, you would never experience impact between the power face of the paddle and a submerged object, but in fact this DOES happen. Based on what happens with paddle-smacks in rivers, I just betcha that video analysis would show that paddle slippage speeds of 2 miles per hour are not unusual. The period of slippage is just too breif to get a good look at it, but impacts when in current tell the story. (I had to edit this a bit after converting some sample slippage speeds from miles/hour to inches/second. I think the present figures are believable).
By the way, your example of a stuck car with one spinning wheel makes some sense on the face of things, but the logic is actually tainted by a common misperception of what forces are being applied to the car when one wheel spins, and what has to be true for the car to start moving again when shifted into four-wheel drive (at the crux of the issue is the lack of relevance between where power is expended and the amount of force applied to the vehicle by each wheel while that is happening). You might find it interesting - it is a very simple concept once one really understands differential gears - but now may not be the time to get into that subject. I've explained this before when the subject of getting stuck was discussed, but I doubt many remember.
that makes sense
Slippage
Let's begin with the GBG example of a kayak moving forward at 5 mph. Let's say this is a tandem kayak being paddled out of synch by two endurance paddlers. And let's say they want to increase their speed to 6 mph but remain as efficient as possible.
Controversial methods aside, there are two ways they can do this: (1) they can increase their stroke rate. According to the GBG example above, they are already maintaining a paddle movement of 7 mph toward the back of the boat. If they increase their paddle movement to a speed of 8 or 9 mph, the difference between boat speed and paddle speed increases further and the slippage of their paddles (or loss of energy with each stroke) will also increase -- and even if they can attain and hold their goal pace, it will not be very efficient.
(2) They can use paddles with larger surface area, thus increasing power available with each stroke. This may work for them if they have the strength and cardio-vascular fitness to maintain the same pace while using the larger blades.
There is a 3rd way they can accomplish this that is available only to paddlers of multi-person boats: they can synchronize their strokes such that their two paddle blades act as a single blade. The bigger blade allows a paddle movement that is slower overall and closer to the speed of the boat, thus reducing the wasted energy of paddle slippage, and therefore allowing them to reach their goal of 6 mph without either increasing blade size or rate. Pretty cool, huh?
* * * * * * * *
Would it be inaccurate to say that the most efficient way to attain a given boat speed (let's say 6 mph) is to minimize the speed of paddle action (let's say 7 mph) while maximizing blade size in context with desired speed and physiological limits?
In other words, the most efficient paddle stroke is not a pin wheel stroke where the speed of paddle movement far exceeds the speed of the boat, but rather a slower stroke that minimizes slippage (paddle movement relative to the water) and that utilizes a blade "just big enough" to achieve the target speed.
* * * * * * *
I played around with some slippage calculations as well:
90 strokes per minute = 5,400 strokes per hour
If a speed of 6 mph, then in one hour:
5,400 strokes per 31,680 feet
Doing the division
1 stroke = 5.86 feet
So the paddler moving forward at 6 mph and maintaining a stroke rate of 90 strokes per minute advances the boat approximately 5.86 feet from each stroke.
If paddle slippage is 1 - 2 feet per stroke, that would mean in a perfect "no slippage" world, that same paddler would move at apx. 7 feet per stroke or 7.2 miles per hour. If slippage (or energy lost to moving water) is in the area of 10 - 15 percent of potential (as we both have guestimated, than slippage is a much more significant factor than loss of speed between strokes, which I wouldn't think would be more than 0.3 mph (4%) , even at 60 strokes per minute.
Where do I sign up to take a course on this stuff?
I’m glad I’m not the only one …
… who is curious enough about this stuff to run problems like that in my head. Years ago, when I first “stepped-up the quality” of my solo boating adventures by getting my little 12-foot pack boat, I was so enthralled with the increase in performance over the 12-foot Jon boat I’d been using for years before that time that I actually counted strokes while running my GPS for the return trip of a two-way , three-mile crossing, then calculated distance per stroke by comparing the number of strokes to the GPS record of distance. I even remember the results (5.0 mph and no stroke count on the trip across, and 4.5 mph and 18 feet per stroke on the trip back), but I have no idea how much slippage there was. To keep from losing my count I had to assign successive counts of 100 strokes to successive screws in the gunwales, using the gunwales as sort of a mental chalkboard. Of course, there’s no direct comparison possible between observations of a semi-utilitarian rowboat and a kayak, but I’m sure the basic principles are the same.
On the other hand, thank goodness I just “forget about the details” most of the time and just enjoy what’s out there to be seen. Makes me think it might be time just to write about another recent paddle trip. I haven’t done that in a while.
rotation
Two points:
- I have tried to get Burke’s math to work and I can’t. Perhaps the explanation in the paper is incomplete, but no matter what parameters I use (he doesn’t say what he uses), the in-sync paddlers are slower. I think most of those on this board have concluded that the model is too simple to be right…but as best I can tell it doesn’t seem to be right on its own terms. I am by the way an economist not a hydrologist and I know how much confidence economists engender these days…but I do have an undergrad degree in engineering. Nonetheless I’d be happy to be corrected by someone who does this stuff day to day.
- It does seem to me that the right way to proceed from an analytical modelling perspective is to recognize as above that there is an optimal gap between paddle speed backward and boat speed forward to minimize slippage–and the math supports this idea. If this is true then in the in-sync case paddle velocity would optimally rise right up to the point of the release but in the stylized out of sync case paddle velocity would be constant. So question is whether there is a natural reason that paddle velocity would rise through an efficient stroke. In a kayak this seems natural due to the fact that our paddle more or less rotates around our body. Thus for constant angular velocity the speed backward of the paddle would be highest when the paddle is perpendicular to the boat. For a canoe this might be less clear but perhaps some of you have views on this.
Instead of trying to understand all the
nautical engeneering BS, why not just take a look at the first, second and third place finishers in all the higher end races, and you will see it is obvious that a tandem kayak with the paddlers in sync is the fastest.
Jack L
The reason has already been …
... mentioned several times, but to directly spell it out, most of us don't give a crap about what works best for races, especially because not all things in the racing world are directly transferable to paddling at normal speed. Most of us never get our boats up to hull speed (or faster) for more than a few seconds at a time. A good example of this kind of thing is the J-stroke in canoeing. People who focus on racing will tell you that it's waste of time to learn the J-stroke, while people who enjoy making certain kinds of "regular" canoes do what they do best think the J-stroke is just fine. Finally, some people LIKE to understand things and find it boring to just do things without thinking about them. I know a few people who have exactly the opposite mindset, and there are times when they do things that don't make any sense at all just because thinking about how things work is something that would never occur to them, but that's okay if that's what they're comfortable with.
Second that one, Jack!
There is an acute misconception that what is applicable to race speed is not applicable to touring pace: at the end of the day, it is all about stroke rate -technique is constant. In a single season (within weeks) , I have done races/paddles from 200m to 100 miles: the only thing I have ever changed was stroke rate... and seat cushion LoL
Paddling is an Olympic sport (very popular all over the world) thus, a lot of time has already been spent testing what works and what doesn't... I don't waste my time trying to re-invent the wheel -just paddle on.... (and do analyze the guys who finish in front of me) LoL
Regards,
iceman
do you think there's a difference paddling in synch on one side or paddling in synch on opposite sides where the cockpits are located far apart as long as the aft blades are entering water undisturbed by the foreward paddler?