I wrote: >>>>>Given that the double skull rowers were probably generating twice the horsepower (or watts) as the pedaler (and given that a double scull is faster than a single scull) the advantage of the pedal boat must have been in the much better efficiency of a screw propeller vs. oar blades for propulsion and the constant delivery of power from pedaling that could maintain a more uniform (and therefore more efficient than surging and slowing like the rowers) speed through the water.<<<<<, Niels misinterpteted it: >>>>I think there's something more to the non-uniform power of the rowers than just the gaps in their power-output. They slide back and forth in their boat, constantly pushing the boat over its hull speed and slowing back down with just their moving mass. That can't be good. Perhaps rowers shouldn't row in sync to avoid that problem - they'd just have to find a way not to bump into each other and get their paddles tangled.<<<<<< I had previously written on Paddlewise during this discussion: >>>....because you don't want to let the kayak slow much between strokes because accelerating the kayak again requires a lot more energy than maintaining a given speed.<<<< Previously Niels had written this in response:>>>>Just accelerating and decelerating doesn't cost any energy, unless you put on the brakes. Look at a weight on a spring: It keeps bumping up and down forever.<<<<<<< I had responded:>>>>We don't live in a vacuum. Drag due to friction is always putting on the brakes. You are more efficient travelling a given distance by going slower because there is less drag at a slower speed. But if you are trying to maintain a speed (even just 3 knots) with a paddle stroke you don't want to slow down much between strokes because accelleration is needed to get back up to above 3 knots again (to maintain the average of 3 knots). Even without the necessary accelleration effort to regain the lost speed the time spent going faster than 3 knots uses more energy resisting the greater drag than the time going slower than 3 knots does when your speed varies.<<<<< Niels, it looks like you have come around to my point of view and have discovered accelleration loses (and are now using it to critique something I wrote because I didn't spell it out again in detail but only implied it). *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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