@willowleaf said:
Somebody on another paddler forum posted a 26 ounce Werner carbon Kalliste paddle for sale for $320 and somebody else posted the comment that “you can get a carbon paddle from Academy Sports for $99”.Out of curiosity I looked at the Academy website and they do have a “carbon” paddle by Magellan for $149. It weighs 50 ounces!! 50 ounces is almost a pound heavier than most “barbell” aluminum and plastic tourist rental paddles! Also, half the buyers who reviewed the model reported that the shaft broke early on during use. Such a bargain!
I pointed out that using a 50 ounce paddle rather than a 26 ounce paddle would mean that you were swinging almost 1.5 extra tons of weight per hour.
30 strokes per minute x 60 minutes = 1800 strokes x 24 ounces = 43,200 ounces divided by 16 oz/pd = 2,700 pounds.
Second commenter said “I don’t think your physics/mathematics make sense”. Numbers don’t lie. Engineers, weigh in.
Well if you’re going to throw out nerd bait you’ll catch me almost every time.
I think your analysis is fine as a first approximation (especially since you have stated your assumptions) and interestingly enough this site has an example that follows your logic exactly.
But there are some details…
You don’t really lift the whole paddle each stroke, it seems more like you lift one side. The motion is pretty complex but I think kayak paddles sort of pivot around the center. So maybe you “lift” only half the paddle…so this would reduce your estimate.
There are dynamic forces involved…since you have to accelerate and decelerate the paddle. Those forces increase with weight and would add to your estimate.
There’s some effect of mass distribution…even intuitively if you add 20 ounces to the center of a kayak paddle shaft it would be easier to use than if you added 10 ounces to the tip of each blade. I suspect that a 50 ounce kayak paddle would have heavy blades and this would add to the overall effort (since the cg of each half of the paddle would move closer to the blade).
I found a tennis racket swing weight estimator that seems to highlight the four key factors.
http://twu.tennis-warehouse.com/learning_center/swingweight_calc.php
And oh my goodness we haven’t even touched on wind resistance. (nerd humor).
On the subjective side I can tell you that if you do sit and switch with a canoe paddle and double the weight of the paddle it takes a sh!tload more work.
Make sense?