Bent vs. straight paddle - direct comparison plus bonus footage

[Alan Gage]

I cleared my social calendar this evening so I could run another paddle test. It was a beautiful evening with light winds and mostly clear skies. I wanted to test the speed difference between a carbon bent and a carbon straight. Unfortunately it's not quite an apples to apples comparison as the longest bent I have is 50" and the shortest straight I have is 53". Both are ZRE paddles with the bent weighing 10.5 ounces and the straight weighing 13.5 ounces. Also along for the ride is a 57" straight shaft weighing 27 ounces for the bonus footage at the end.



I also decided to switch up the boat. I went with my Bloodvein which was my main tripping boat. It's 16.5' long and weighs a little over 40 pounds. Max width is 30" with some good tumblehome in the center. Rocker is I don't remember what but it's considerably more maneuverable than the Barracuda I was paddling in the other test and also more maneuverable than the Magic I used to own. I think it turns pretty well when empty. Less so when loaded for a trip. I designed it for tripping both upstream and downstream on rivers as well as lake travel. Below the water line it's fast and above the water line it's a big fat hoggy to hold me, the dog, gear, and to avoid plunging into waves. I took it on a 30 day trip as well as a 43 day trip so it's got credentials.

20160403_003 by Alan, on Flickr

Same setup as the last test. Paddle for 2.2 miles with a heart rate of 120 bpm, rest a couple minutes, and paddle the same 2.2 miles with the other paddle at the same heart rate.

After that test it's .5 mile with each paddle at a heart rate of 100 bpm.

I feel the 120 bpm is similar to hard yet sustainable tripping output that would be used paddling into the wind or pushing to get to camp that might still be hours away. The 100 bpm paddle is similar to a more relaxed all day tripping speed.

Both paddles were tested seated with hit and switch technique.

So, without further ado:

Bent shaft - 2.2 miles

• Average heart rate - 119 bpm
• Average speed - 5 mph (8 kph)
• Time - 26:29

Straight shaft - 2.2 miles

• Average heart rate - 119 bpm
• Average speed - 5 mph (8 kph)
• Time - 26:14

Bent Shaft - .5 miles

• Average heart rate - 99
• Average speed - 4.4 mph (7.1 kph)
• Time - 6:53

Straight shaft - .5 miles

• Average heart rate - 99
• Average speed - 4.4 mph (7.1 kph)
• Time - 6:52

Impressions were that while the straight shaft actually beat the bent in terms of time it felt much less comfortable due to the extra length. I was going to use the straight shaft first but after using it to warm up I could tell there was likely to be some muscle fatigue so I went with the bent shaft first and finished with the straight. I could really feel it in the muscles of my triceps and shoulders as the top hand was higher than I'm used to.

I felt like I was reaching much farther forward with the longer straight to get a comfortable stroke and I also felt that the stroke rate with the straight was considerably slower. So I was surprised when I counted the strokes and found the straight to be 59 spm and the bent to be 60 spm. I think I may have been subconsciously speeding up the recovery to make up for the longer stroke.

And now for the bonus footage:

I brought along my 57" straight paddle to try some single sided kneeling. I didn't even try doing that at 120 bpm and went straight to the .5 mile paddle at 100 bpm. Single sided paddling is not my strong suit and I really felt on the verge of control at this power output. Somehow this recording did not get saved but I can give you a pretty good idea.

Because of the long recovery phase it was difficult to keep my heart rate up. It settled at around 93 bpm and the speed was right around 3.9 mph (6.3 kph) when things were going well. A little less than that when things were not going well.

After that I decided to just cruise at my site seeing pace while kneeling single sided with the 57" straight paddle and this felt much better. Control was fine and I felt relaxed. This is how I normally use this stroke. Speed was 3.3 mph with a heart rate of 83 bpm.

Then I sat and used single side correction strokes with the 50" bent, also at my site seeing pace. Results were 3.4mph with heart rate of 83 bpm.

Thoughts? Critiques?

Alan

 

[Glenn MacGrady]

Impressions were that . . . the straight shaft . . . felt much less comfortable due to the extra length. . . . I could tell there was likely to be some muscle fatigue . . . . I could really feel it in the muscles of my triceps and shoulders as the top hand was higher than I'm used to.

This is why I said in the other thread that bents are more effortless and less tiring for me than straights for hour-after-hour single-sided correction strokes, speed being irrelevant to me. Unless I go to switch paddling because of wind or up-current attainment, in which case bents are much faster than single sided correction with a straight (or bent) and much easier to switch with than a bent.

As to speed for those paddlers and times when it is relevant, and notwithstanding any of the science-modeling articles I've posted, 50 years and tens of thousands of flatwater and ocean racers have proved beyond peradventure that bents are faster than straights. It's not arguable.

After that I decided to just cruise at my site seeing pace while kneeling single sided with the 57" straight paddle and this felt much better. . . . This is how I normally use this stroke. Speed was 3.3 mph with a heart rate of 83 bpm.

Then I sat and used single side correction strokes with the 50" bent, also at my site seeing pace. Results were 3.4mph with heart rate of 83 bpm.

This is consistent with my recollection, from when I used to GPS myself, that I cruise on my knees with correction strokes at about 3.0-3.5 mph and don't get winded. Even now at 80. And even though other simple tasks can wind me. I suppose it's related to my heart rate doing various tasks, but I've never measured my heart rate.

To digress from our speed and efficiency topics and tests, I find that straight paddle use is more aesthetically pleasing and gives me more physical and mental motion pleasure than bent paddle use. You can do more strokes and moves and blends; it's more sophisticated and elegant. Solo, at least.

 

[yknpdlr]

To digress from our speed and efficiency topics and tests, I find that straight paddle use is more aesthetically pleasing and gives me more physical and mental motion pleasure than bent paddle use. You can do more strokes and moves and blends; it's more sophisticated and elegant. Solo, at least.

I absolutely agree. although I use my carbon bent much more than my wood straight paddles, it is because most of my solo time on the water is spent training and conditioning to go fast than simply cruising just for fun. There are so many more and different kinds of strokes and linked strokes to effect the feeling of just "messing about in boats" that are possible to make the canoe perform with exacting precision while efforlessly cruising along a random shore edge to do my will with a favored straight wood shaft than any bent can possibly do well.

“Believe me my young friend, there is nothing – absolutely nothing – half so much worth doing as simply messing about in boats.” So says Ratty to Mole in Kenneth Grahame's classic novel 'The Wind in the Willows'.

 

[memaquay]

3.4 mph sounds very similar to my tripping speed, even the heart rate seems about the same. 8 k an hour over an extended day of tripping would not be doable for me, even if I switch hit. I might have very short bursts of 7 to 8 kph, but they would be for a particular reason, such as speeding away from a charging moose or something. I'm gonna stay OG in this conversation though and stick to my guns, and keep single sticking on one side, and look askance at those who don't.

 

[gumpus]

Very cool Alan. I assume you were blindfolded to avoid confirmation bias.

I usually cruise kneeling using hit and switch with a 6 degree bent shaft. I've ling been curious why I like it so much.

Regarding bent vs straight my subjective impression is that even with identical length the bent shaft softens the catch and that can help with long-term comfort. On the initial catch the boat has the highest resistance to acceleration and with a straight shaft being at it's most powerful angle at the beginning of the stroke I sometimes feel a little tug on my shoulder which may affect how hard I paddle long term while a bent (6 degree for me) smooths things out and adds significant long term comfort. But when I need as much immediate power as possible like running a drop upstream I always use a straight shaft.

When I paddle a straight keel boat like Advantage it also strikes me that the boat is a little harder to accelerate at the beginning of the stroke than a rockered boat that feels like the bow lifts up and skids over the water a bit so my subjective impression is that a 12 degree bent complements a zero rocker sitting boat nicely.

 

[Alan Gage]

This is why I said in the other thread that bents are more effortless and less tiring for me than straights for hour-after-hour single-sided correction strokes, speed being irrelevant to me.

I assume your straights are longer than your bents? If they were the same length do you think you would notice a fatigue difference?

I find that straight paddle use is more aesthetically pleasing and gives me more physical and mental motion pleasure than bent paddle use. You can do more strokes and moves and blends; it's more sophisticated and elegant.

I would agree with that and that's one of the things I've been thinking about lately. If a straight paddle of the same weight and length has the same performance as a bent then why not use the straight and have more capabilities/options?

As to speed for those paddlers and times when it is relevant, and notwithstanding any of the science-modeling articles I've posted, 50 years and tens of thousands of flatwater and ocean racers have proved beyond peradventure that bents are faster than straights. It's not arguable.

I believe it is arguable. Not from a racing point of view but from a tripping point of view. For a tripper I still see no evidence that bent shaft has any benefit in speed or efficiency over a straight shaft, all else being equal. Nearly all the comparisons I see are comparing a short carbon bent to a long straight wood.

8 k an hour over an extended day of tripping would not be doable for me, even if I switch hit. I might have very short bursts of 7 to 8 kph, but they would be for a particular reason, such as speeding away from a charging moose or something.

I think I could do it but it certainly wouldn't be enjoyable. Also, the speed when loaded for tripping would be a good deal slower than when empty at the same heart rate. But that pace does have its purpose, such as racing to shore for a bathroom break after eating too much jalepeno bannock and it's been interesting to see that, so far, any paddle should get you there about as fast as another.

Regarding bent vs straight my subjective impression is that even with identical length the bent shaft softens the catch and that can help with long-term comfort. On the initial catch the boat has the highest resistance to acceleration and with a straight shaft being at it's most powerful angle at the beginning of the stroke I sometimes feel a little tug on my shoulder which may affect how hard I paddle long term while a bent (6 degree for me) smooths things out and adds significant long term comfort. But when I need as much immediate power as possible like running a drop upstream I always use a straight shaft.

Interesting. I'll have to start paying attention to that. I've generally only used a straight when I'm running whitewater or when I want to play around with stroke techniques. I'll certainly be using it more for forward propulsion and will see if I notice the same thing.

Alan

Alan

 

[Tryin']

[Snip]

I also decided to switch up the boat. I went with my Bloodvein which was my main tripping boat. It's 16.5' long and weighs a little over 40 pounds. Max width is 30" with some good tumblehome in the center. Rocker is I don't remember what but it's considerably more maneuverable than the Barracuda I was paddling in the other test and also more maneuverable than the Magic I used to own. I think it turns pretty well when empty. Less so when loaded for a trip. I designed it for tripping both upstream and downstream on rivers as well as lake travel. Below the water line it's fast and above the water line it's a big fat hoggy to hold me, the dog, gear, and to avoid plunging into waves. I took it on a 30 day trip as well as a 43 day trip so it's got credentials.

20160403_003 by Alan, on Flickr

Not to thread jack, but I really want to know more about this boat. Is there a thread somewhere?

Edit: found it.

Composite Bloodvein build

Version 1.0 was a success so V2.0 will be a carbon/kevlar version. Best case scenario is cutting 10 pounds, from 48 to 38. I think 7 or 8 pounds will be more realistic though. Made a couple very minor changes to the hull. The entry and exit lines were pretty hollow on V1 which made it a little...

www.canoetripping.net

 

[Alan Gage]

Not to thread jack, but I really want to know more about this boat. Is there a thread somewhere?

Edit: found it.

Composite Bloodvein build

Version 1.0 was a success so V2.0 will be a carbon/kevlar version. Best case scenario is cutting 10 pounds, from 48 to 38. I think 7 or 8 pounds will be more realistic though. Made a couple very minor changes to the hull. The entry and exit lines were pretty hollow on V1 which made it a little...

www.canoetripping.net

There is a bit more info on the design in the build thread for version 1:

Solo expedition build

Last build of the season before the water opens up. No doubt open water will appear before I'm done but there will still be plenty of cold and windy days to work in the shop. This will be, hopefully, my ideal solo expedition canoe....or at least a step in the right direction. The aim is to...

www.canoetripping.net

The only changes to the composite version was a slight softening of the stems and slight revision to the first and last couple forms. This made it a little more maneuverable in moving water with less sticky stems. It made quite a difference, in a good way.

Here is its trip report:

Wollaston Lake to Goose Lake (Nunavut Border) and back

I'm going to post this in sections as I write it to keep it from getting too overwhelming (for both you and me). I'll post the follow ups in responses to this thread. It’s a long drive from Estherville, IA to La Ronge, SK. By the time one has traveled that distance it feels like one is nearly...

www.canoetripping.net

 

[Gamma1214]

Speed & efficiency comparisons are worthy of discussion but, for me, there's simply no comparison between a wooden straight shaft and anything made of plastic / carbon. I love the thought that I am seeing places the way that they were first seen, whether that is walking, riding a good horse or paddling a canoe.

Would the illusion be complete with a bent shaft made of carbon or even a kayak paddle? Perhaps. The fact that I paddle strippers instead of birchbark (or even wood canvas) doesn't seem to be detrimental to the experience... still, I'll keep using homemade single sticks just in case.

("old ways are the best ways"- lest we forget)

 

[Alan Gage]

Speed & efficiency comparisons are worthy of discussion but, for me, there's simply no comparison between a wooden straight shaft and anything made of plastic / carbon.

Nothing wrong with that and I'm not trying to convince anyone to necessarily switch paddling styles. It's just that for a few years I've suspected there really wasn't a big difference between doubles and singles or straight vs. bent when it came to tripping and I wanted to see how it played out when tested. Even if the double would have blown the single out of the water during that test I wouldn't have switched to a double simply because I prefer the single, which is what really matters.

Paddle what makes you happy.

Alan

 

[Glenn MacGrady]

50 years and tens of thousands of flatwater and ocean racers have proved beyond peradventure that bents are faster than straights. It's not arguable.

I believe it is arguable. Not from a racing point of view but from a tripping point of view. For a tripper I still see no evidence that bent shaft has any benefit in speed or efficiency over a straight shaft, all else being equal.

I still disagree with you because no matter the paddle stroke rate difference between racing and tripping, for example, the physics of each stroke is the same for the bent and straight paddles.

According to Dr. Burke's research, with a 12° bend the paddle is moving at maximum velocity (propulsive force) exactly as the blade is vertical to the water. That means all the vector force of the forward stroke at that point is pointing forward. A straight paddle, in contrast and regardless of stroke rate, reaches maximum velocity before the paddle blade is vertical. That means only part of the vector force of the forward stroke is pointing forward (the rest is pointing upward).

Burke uses a curves to demonstrate that the bent shaft paddle reaches a higher propulsive force on each stroke and reaches the maximum propulsive force later in the stroke than the straight shaft, just when the bent paddle blade is perpendicular to the water.



As he describes this graph,

"the figure shows that the straight shaft paddle reaches its maximum direction cosine value when the shaft (and hence the blade) are perpendicular to the water. Unfortunately, this occurs before the relative velocity reaches its maximum value; engineers would conclude that the direction cosine “leads” the relative velocity for this paddle. By contrast, the paddle with a 12-degree bend maximizes its direction cosine at the moment that the relative velocity hits its maximum. The bent shaft’s blade angle is in phase with the relative velocity. The blade is perpendicular to the water’s surface when the relative velocity is maximum. This is a good thing."

Charles Burchill has a video that attempts to show the verticality positions of a straight shaft paddle (green) vs. a bent shaft paddle (orange).

In any event, my interpretation is that regardless of stroke rate—whether a racing, tripping or other recreational stroke rate—every stroke with a bent shaft paddle will have greater forward propulsive velocity than a straight shaft paddle applied with the same force, because the bent shaft blade is more vertical to the water than the straight shaft paddle when they are at their respective points of maximum velocity.

 

[lowangle al]

I agree that a bent shaft will probably have more forward propulsion when using the same stroke. But, is the most efficient stroke with a bent shaft the same stroke as it is for a straight shaft? Maybe not, the bent might be better for your average guy doing the average commonly used stroke.

Kudos to Alan for doing these tests. He did a great job making meaningful comparisons leading to information we can use. I would like to do my own test, comparing the speeds when paddling from the stern seat to a more centralized position like the bow seat facing backwards. All I need is a heart monitor of some sort.