LoL
Love people that try to re-invent the wheel… when they only just run…LoL
Similar thought
With an intermittent power application some of the force of each stroke goes to accelerating the boat rather than overcoming drag.
In the portion of the stroke where there is no power applied drag is decelerating the boat.
If the power application were constant the force that is going to acceleration would be used to overcome drag, and the speed should increase.
Weight comes in to, and I’ve thought that there should be an optimum weight - lighter might not be be better.
I’m too lazy to write out all the equations though.
OK I get it
When you don’t understand a discussion, you make fun of it - message received.
How crisp and efficient are your turns
if you are out of sync?
Dogmaticus
Nope, I don’t think you do…
– Last Updated: Sep-30-10 2:32 PM EST –
this is just one of those ridicules discussions,..., the world is round, and one is trying to prove is flat -with dragons around its ages waiting to eat anyone that tries to cross the Atlantic!
In fact, top academicians of the middle-ages used to support such statements LoL
OK
OK, I’ll explain my position - I am a professor of engineering, and am currently building a hydrodynamics laboratory. It will have experimental facilities capable of testing exactly this type of situation (intermittent power application in paddle craft).
I am engaged in this discussion because it is 100% relevant to an upcoming research project. Linked articles notwithstanding, I know of only 1 group that has done experimental research on this subject. It is early work, and not conclusive. So while I trust the statements of tandem kayak racers, and have respect for their opinion, until the physics of what is happening are understood, their opinions are only anecdotal evidence.
If you dislike or don’t believe in the merit of this discussion, by all means avoid it. Ridiculing a discussion that you don’t or won’t understand is a manifestation of ignorance that I have no patience with.
In sync is at its best when
both of the paddlers have the same optimum stroke rate of efficiency.
Your different lengths of paddles would definitely throw that way off. Other factors like maintained strength and overall fitness will also contribute to optimum sync.
Agree with Carldelo
I agree with Carldelo about the seeming advantage of paddling out of synch. At constant velocity you would avoid wasting energy from the extra (non-linear) drag from sudden acceleration, and then rest. I have not spent time to sort out what is wrong with the theory presented on the web page (see well above), but hope to since I have sufficient training to follow it. It is possible (?) that paddling in sych was developed simply because racing kayaks are not normally long enough to paddle out of synch. And, although it seems petty, paddling in synch “looks good”.
I am also intrigued about paddling out of phase. I asked this question months ago (look for my name in the history) and had zero response last time I looked. Paddling out of phase might help tracking so that the boat would not follow a zigzag path. Very minor, I admit, but a discussion of interest at least to me.
Cheers, Northyak
anecdotal or empirical?
Trusting “anecdotal” opinions is not the same as accepting empirical evidence.
The article made a lot of sense to me. What doesn’t make sense to me is the response of a few here about the supposed efficiency of maintaining a race speed of a tandem by paddling out of sync. Guess people have not experienced the phenomenal energy demands it requires to paddle at or above (yes, I said that correctly, above) hull speed.
OK, here is my experience.
There is no way, no way at all, for a tandem paddler, by paddling out of sync, to reach racing speeds.
The resistance is much greater than the same speed for a solo boat. More wetted surface, not only due to the longer boat, but also the greater draft due to the weight of two people. Also, there is also overcoming the mass. So, by paddling out of sync, I am now responsible for overcoming not only my mass, by myself, but also another person? No way.
Let me tell you, it is not only paddling by getting the blade exactly in and out of the water at the same time, an amazing component is matching the phase of power application. Two less strong paddlers can out-race a more powerful duo by employing this level of finesse.
Just my experience. Racing K-2’s, K-4’s, marathon canoes, OC-2’s…oh, yeah, a few races in plain old sea kayaks. I have had years of experience coaching athletes in sprint boats, as well.
Agreed
I’m saying anecdotal in that it is not quantitative data, collected in a systematic way, comparable to other data. Empirical is another word for that, I think, depending on how you define it.
The point was made above that at race speeds (at or beyond hull speed) sync paddling makes sense (and you say is required, with a good argument), while for general paddling, the more uniform power application of out-of-sync paddling will require less energy overall.
So I think that’s interesting, and it also implies that there is cross-over point, where you should switch paddling mode. It would be nice to figure out where the cross-over point is and why.
Something for nothing?
– Last Updated: Sep-30-10 9:15 PM EST –
My thinking is that you can't get something for nothing. Laws of physics...
In the ideal case (yaw, balance and other factors ignored and purely looking at the paddle force propelling the boat forward), if both paddlers exert the same effort, they should get in return the same average speed, regardless of whether they exert that effort in-sync or not. But that would be if the resistance vs. speed was linear and it is not.
So, in fact, if they paddle in-sync, they should be slower, IMO (again purely theoretically, looking at force delivered by the paddlers vs. drag at a given speed).
As carldelo said, during an in-sync power phase, the boat will lurch forward, hitting higher speed than the average. During that time it meets higher resistance than at any other time. If we recall the charts, the resistance rises exponentially, thus the faster one paddles the more energy gets wasted to resistance so to speak. E.g. if one paddles twice as fast one is using much more than twice the power!
So, the only way one can increase the average speed by paddling faster is by using MORE energy. Since our premise is that the two paddlers use the same energy in both cases, it clearly seems to me that out of sync (e.g. opposite phases - one powers/one recovers) should be more efficient since it paddles at the maximum speed they can sustain without jumping above it and wasting energy on the relatively higher resistance there...
Now, someone with time on their hands formulate that -;) I think it is a matter of integrating the force the two paddlers deliver over time: in both cases it is EXACTLY the SAME - the paddlers are not getting any stronger. So, for that same time, integrate the resistance for both cases. In the first case - the resistance is constant. In the second, one needs to know how much the boat slows down b/w strokes and how fast it goes at the in-sync power phases; to calculate that one would need the mass of the boat + paddlers... Then, subtract the integrated (total) resistance from the "total" force in each case to get in which case there is more "force" left -;)
Amusing anecdote
I am curious to know if there is a “crossover” point of efficiency between a sort of constant power application by paddling purposely out of sync, vs paddling in sync. Interesting concept.
Story- in '07, I was with a group of friends on a 10 day, 140nm trip from Port McNeil to Campbell River. Two paddlers we put in a Triton double- very petite women (98lb, 110lb)- with the intent they could keep up with a strong group. One of these women is crazy strong, but not very polished in technique. The smaller is fairly fit, but not strong, with phenomenal technique (paddled K-1’s for a few years).
For the first three days, it worked great- they stayed at the head of this strong group (I do not use that term lightly, this was…a very, very,unusually strong/fit group). Our days were typically 16-20nm during those days.
Then, they fell apart. Badly. They struggled to keep up, and were getting frustrated.
We had put the one with the great forward stroke in the bow- she kept cadence like a freaking metronome (cellist, that figures). What was very apparent was that the stern paddler was out of phase- this was in comparison to the first 3 days, when they were obviously in sync.
The last two days we took the stern paddler out, and put her in my boat. While too big for her, she was at last happy. I took over the stern seat. Paddling at an assertive, but still all-day pace, and perfectly synched, we easily pulled away. The solution was to have everyone else draft our wake, which they did so with glee.
Although a non-race pace, it was still apparent that in a loaded boat, paddling in sync was significantly superior, and easier.
An unloaded boat, at non-racing speeds? Hmmm, that could be different. Maybe I should pull out the heart rate monitor and GPS, and paddle the Triton in and out of sync this Sat (the very petite but highly skilled paddler is my wife, the Triton is our boat).
isn’t it a function of the same cadence?
whether in or out of sync if you’re the same cadence then you’ve got two blades hitting the water at the same time. I’d guess the issue of needing to be in synch on the same side is simply a consequence of length restrictions and that’s it’s prefereable to have the paddlers in the center of the boat and not the ends.
I would be inclined to agree with you if
both paddlers were exact same equals as engines,
but just like in a canoe, where we are on opposite sides, a hut is usually called to keep the boat from yawing to the opposite side of the more powrful paddler.
I know it is called for a change in arms also.
You can’t do that with a double blade in a kayak though.
I think it would be interesting to get two equal paddlers,(with two equal strokes) and then have them timed in a given course, twice.
Once in synch, and the other on opposites sides.
jack l
Sounds good
I like the argument, but it really needs to be modeled with a realistic force-time curve to be a legitimate analysis. Out-of-sync paddlers with real force-time curves will also experience intermittent accel/decel phases, just less extreme than the in-sync case.
After thinking about it, I suppose it may be self evident that in-sync paddling is necessary at high speeds, when the drag on the hull is greater than the force that a single paddler can exert on his own. I think…
Three cases
People seem to be talking about different scenario, which is maybe leading to some miscommunication.
I think there are three cases:
- Paddling in sync, both blades in the water at the same time on the same side of the boat.
- Paddling in sync, both blades in the water at the same time on opposite sides of the boat.
- Paddling out of sync, only one blade in the water at any time. Sides will necessarily alternate.
Forward Stroke
– Last Updated: Oct-01-10 12:07 PM EST –
To support out of sync paddling, it's a clear evidence of lack of understanding of the forward stroke. This does nothing to do with "boat design" or "engineering" for that matter -it has to do with the physiology of the sport in itself.
A kayak/canoe is not a "paddle boat" as used to be seemed in Southern US. The paddle of the "paddle boat" works as a propel -moving water. The paddle of a canoe/kayak should not move water, it should allow the paddler and his/her craft to move through a fixed point: the catch.
Yes, once the paddle is planted in the water -it should not travel through the water- it should be still in that particular point. The paddler/boat should move pass that point as if you were pooling....
In addition, there should be some pause (millisecond pause) between stroke to allow a gain from the glade of the boat (without energy expenditure) and to apply greater power during the next stroke...
Therefore, the two or four paddlers (k-2 or k4) need to plant the blade in the water at the very same time (fixed point) and they should rest at the very same time (while the boat glides) and again apply power at the very same time during the next phase.
Really, I don't worry whether you understand this or not (you are free to believe wherever you want); however, it does annoy me that people starting in the sport come to this site for help and knowledge, and they end up learning/acquiring all of these ridicules ""trues"".
Hope you have a nice day!
Nonsense
Your post demonstrates a fairly comprehensive lack of understanding of the physics of paddling. I DO understand what you are saying, and it is not correct.
Good point
For high speeds it seems necessary to paddle in-sync. Paddling out of phase (e.g. one power the other recovers) is, I think, still going to result in a higher average speed if in both cases the energy spent is the same and somewhat below the peak each paddler can handle.
May be some of these tandem guys out there with GPS and heart rate monitors can test that theory -
Not sure if you realize that you are are
arguing with one of the more knowlegeable and top rated K-1 racers in the east.
I sure as heck would take what he says as being correct.
jack L