The efficiency of bent vs. straight shaft paddles

[yknpdlr]

If there is no significant speed advantage, someone has to please tell me why in every one of hundreds of canoe races I have been in or seen, 95% of canoe racers adopt using bent shaft carbon paddles and will finish well ahead of 95% of (mainly first time racing beginners or "tourist paddlers" in the race) who paddle the race using straight wood paddles.

 

[Alan Gage]

If there is no significant speed advantage, someone has to please tell me why in every one of hundreds of canoe races I have been in or seen, 95% of canoe racers adopt using bent shaft carbon paddles and will finish well ahead of 95% of (mainly first time racing beginners or "tourist paddlers" in the race) who paddle the race using straight wood paddles.

In the races I've attended there is a very small percentage of truly top tier paddlers and they often finish very close to one another, sometimes seconds apart after an hour or more of racing. I don't doubt that a straight vs bent shaft might be the difference in them winning or losing but I still don't think it makes a significant difference and I certainly don't think the reason they're beating the 1st time "tourist paddlers" is because the tourist paddlers were using straights.

If you gave those top tier paddlers straight paddles and gave the rest of the field, even the middle of the pack paddlers (who are no slouch), bents I don't think there would be any difference in the final standings. The top tier paddlers are still going to win, straight or bent, over the rest of the field. The athlete is much more important than the equipment.

I have yet to see anyone that's made a compelling comparison between bents and straights to show that there is a significant (or any) difference that would matter to someone paddling at a tripping or leisurely pace. All the comparisons and studies I've found have compared short bent shafts to long straight shafts. That is if they even did make an actual comparison rather that using models to predict performance in a lab environment.

Alan

 

[yknpdlr]

The subject of recent posts was whether bents were 2.4% (or more) faster than straights. My point above was that it doesn’t take long for a new to racing paddler, wanting to eventually place well, will soon adopt use of a bent paddle in future races. Why?

If all in some odd race were required to use straight paddles only, of course there is little doubt that experienced race paddlers, top tier or middle pack paddlers, would still be the winners above the tourists who are not otherwise well experienced or have trained as race paddlers. i have never seen top finishers complete a race using anything other than a bent.

 

[Alan Gage]

The subject of recent posts was whether bents were 2.4% (or more) faster than straights. My point above was that it doesn’t take long for a new to racing paddler, wanting to eventually place well, will soon adopt use of a bent paddle in future races. Why?

If all in some odd race were required to use straight paddles only, of course there is little doubt that experienced race paddlers, top tier or middle pack paddlers, would still be the winners above the tourists who are not otherwise well experienced or have trained as race paddlers. i have never seen top finishers complete a race using anything other than a bent.

The reason new racers soon adopt a bent shaft is because that's what they're told to do and they are emulating what they see the top paddlers using. They don't want to look like a newbie that doesn't know what they're doing. They certainly aren't running time trial comparisons between bents and straights of various lengths and angles to see what actually works best for them and their paddle stroke.

What they should really be doing is emulating the way the top paddlers train. A bent shaft paddle won't make them a fast paddler but hard and focused training will. But it's a lot easier to drop $300 on a paddle then it is to actually do the training.

Then, after buying a bent shaft paddle that is 8" shorter and 12 ounces lighter than the wood straight paddle they were previously using they're convinced that the bent shaft is what made the difference, not the 8" less length and 12 fewer ounces.

I do not believe that study concluded that bents were 2.4% faster than straights but rather that there was a 2.4% increase in impulse power. This would translate into a less than a 1% increase in speed. This was also not an actual test or comparison. It may or may not transfer into real world paddling and it may or may not apply to all power outputs (is that 2.4% increase only near max power or does it also apply to a more relaxed pace?).

The one thing I took away from that study and trying to make sense of other studies is that it is a complicated and nuanced subject that has not been studied heavily or well.

Alan

 

[kahel]

What they should really be doing is emulating the way the top paddlers train. A bent shaft paddle won't make them a fast paddler but hard and focused training will. But it's a lot easier to drop $300 on a paddle then it is to actually do the training.

how right you are with that statement.

 

[gumpus]

I do not believe that study concluded that bents were 2.4% faster than straights but rather that there was a 2.4% increase in impulse power. This would translate into a less than a 1% increase in speed. This was also not an actual test or comparison. It may or may not transfer into real world paddling and it may or may not apply to all power outputs (is that 2.4% increase only near max power or does it also apply to a more relaxed pace?).

The one thing I took away from that study and trying to make sense of other studies is that it is a complicated and nuanced subject that has not been studied heavily or well.

Alan

Yes. Sean Burke created a theoretical model and the model has not been validated with test data so it could be fundamentally flawed; we don't know but we should be open-minded to better models. Even if we assume the model hasn't missed anything important it applies only to seated paddlers. The 2.4% benefit assumes that the blade drag does not change between a straight and bent so maybe it applies to a straight Zav vs a bent Zav...or maybe that assumption is flawed. There is no basis for comparing one brand of paddle to another.

My take is that if we make all the assumptions made by Sean Burke (body mechanics defined by one paddler, seated paddlers, blades with identical drag coefficients) then there may well be a 2.4% benefit (or more, or less). It would be nice to have a model that can assess other paddle design parameters like weight, dihedral, Cd, edge losses, tip sharpness, ...? I'd like a better understanding of how all paddle design parameters affect efficiency.