It is better, worse or irrelevant for a paddle to be deeper in the water for forward strokes and turning strokes?
"Deeper" could just mean burying the paddle down further than the throat, but let's be a little more technical.
Let's assume the "center of pressure" (COP) is at the geometrical center of a paddle blade. Thus for a 26" long animal tail paddle, the COP is ~13" deep; whereas for a squat 16" racing blade, the COP is ~8" deep.
Which of these two COPs is better for forward and turning strokes? You can assume the total areas of the animal tail and racing paddles are the same if it matters.
If you conclude a deeper COP is worse for efficiency and leverage, what functional reason is there to use a long and deep paddle? There must be something. These paddles are ubiquitous. So, maybe they are better for efficiency or leverage or something.
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Posted by: clydehedlund on Jun-10-14 3:07 PM (EST)
On how much fulcrum you need or want to use?
that's what she said|
Posted by: slushpaddler on Jun-10-14 3:15 PM (EST)
LOL Clyde ... I can see that !|
Posted by: onnopaddle on Jun-11-14 4:59 AM (EST)
Although I've messed with the center of |
Posted by: ezwater on Jun-11-14 1:35 PM (EST)
pressure concept myself. I confess I'm unable to answer your question.
Posted by: rblturtle on Jun-11-14 1:36 PM (EST)
I had a bow paddler, a fellow scout leader, that used a real long paddle and dug deep. He claimed that the deeper the paddle blade is in the water, the less "slippage". I don't know about that, but he could sure move the boat! We need a submarine propeller engineer the chime in.
Posted by: carldelo on Jun-11-14 3:13 PM (EST)
I'll throw in my two cents,|
Posted by: tdaniel on Jun-11-14 4:20 PM (EST)
none of which is physics based but allows for some generalities regardless of craft or even paddle type- canoe or kayak.
that was good.|
Posted by: slushpaddler on Jun-11-14 4:38 PM (EST)
That brings up a question though.|
Posted by: Guideboatguy on Jun-11-14 5:43 PM (EST)
This is a good question:|
Posted by: pagayeur on Jun-11-14 4:07 PM (EST)
Over the years I've seen many folks who paddle Canadian style (tandem canoes paddled from the center station, at a standing heel), using long otter-tail paddles (regular shaft, long blades). I always wondered why? Turns out the sq. inches of area on a long otter-tail blade is about the same as some of my conventional paddles. But they paddle mostly on lakes and I paddle mostly on rivers where a long paddle can be a detriment, so it's moot question for me. But each time I head for a lake, I wonder if I'm missing something. sounds like our Mech. Eng. poster says no.
Posted by: Glenn_MacGrady on Jun-12-14 1:55 AM (EST)
I think that is pretty much correct|
Posted by: pblanc on Jun-12-14 9:45 AM (EST)
Going From Positive to Negative Angle|
Posted by: clydehedlund on Jun-12-14 3:44 PM (EST)
The blade only indicates the amount of forward travel of the canoe. Propulsion is achieved when the blade is "locked" in position. Racers actually remove the blade ahead of where it entered the water.
Posted by: carldelo on Jun-12-14 4:17 PM (EST)
I agree with this analysis, but would add a point - long narrow blades mean that paddling effort ramps up and down more gradually during the stroke, and is probably easier on the joints.
Cab forward paddling with a short slalom|
Posted by: ezwater on Jun-12-14 4:40 PM (EST)
blade does involve a relatively sharp catch, which would be stressful if one were not used to it. The catch should not be savage, or slamming, but should be sharp and definite. If it is done that way, then the bow will come back during the paddle recovery, and a J stroke will normally not be necessary.
Yes, EP vs GP kayak paddles . . . |
Posted by: Glenn_MacGrady on Jun-12-14 7:45 PM (EST)
. . . would present a similar issue.
Posted by: bigspencer on Jun-13-14 12:13 PM (EST)
Posted by: clydehedlund on Jun-13-14 5:44 PM (EST)
And straight shaft too!
Not that I've been paying attention, |
Posted by: ezwater on Jun-14-14 10:03 AM (EST)
but my way of looking at it is that one is trying to move the boat along or around the surface of the water, so the center of effort of the paddle should be near the plane of the water surface.
Posted by: harry0244 on Jun-15-14 9:34 AM (EST)
The farther the center of thrust is from your hands, the more force (pushing on the top, pulling in the middle) you must exert to achieve the same force at the paddle face. As long as the paddle is long enough that you are not wasting energy stirring the surface shorter means easier paddling.