Testing hull efficiency ?

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Jim Dodd
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Testing hull efficiency ?

Post by Jim Dodd » Thu Sep 25, 2014 8:28 am

Has anyone designed a method of testing one canoe against another for efficiency ?

With several canoes, I'd like to scientifically compare them.

I have pondered, taking two hulls and adding weight to them to simulate a paddler, tape a line at the bow, near the waterline, and testing the amount of pull in the current of the river.

Any ideas or suggestions ?

Jim
Keep your paddle wet and your seat dry!

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Patricks Dad
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Re: Testing hull efficiency ?

Post by Patricks Dad » Fri Sep 26, 2014 7:34 pm

oh this is an interesting topic. I have long pondered the idea of putting a small trolling motor on the canoe and carefully measuring current drawn by the motor (via an amp meter) and resulting speed (via GPS) on a calm day. For each hull, you could develop a curve of energy in vs speed achieved across a spectrum of inputs (i.e., throttle settings on the trolling motor). This could lead to a family of curves (one curve for each of several weights/loads in the canoe).

You would have to ensure you had a constant current source to ensure some consistency for the measurements. Note also that the results would include (or be influenced by) the effects of different propulsion efficiencies in the motor itself as it is swept through it's operating range (some initial testing of the motor to find a somewhat linear operating range to test over might be useful or to develop a means to compensate for nonlinearities in the motor's response).

I wish I had time to pursue it.

But your idea seems like a good place to start... :wink
Randy Pfeifer
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Randy.Pfeifer1@gmail.com

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Jim Dodd
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Location: Iowa

Re: Testing hull efficiency ?

Post by Jim Dodd » Fri Sep 26, 2014 7:47 pm

Hi Randy

It seems every method I come up with has it's problems !

I can see the need to vary the power and compare speed curve.

This is not going to be easy !

I've relied on just paddling, but I want something a little more definitive !

Thanks for the ideas !

Maybe something to ponder this Winter.

Jim
Keep your paddle wet and your seat dry!

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