Builders' Forum Archives
Re: square sterned canoe
Posted by Mark Camp on Jan 17, 2006
Smilin' out loud!! The thought of bean burritos of course immediately calls to mind a huge advantage of electric motors: lower emissions. At least until kayak-paddler EGR technology improves. (I understand that they have a prototype working on cattle, but what are you going to do with all that CH4, down on the farm?)
You are right. Max efficiency of today's small brushless DC motors exceeds 90%, and I suspect that the prop does its part, by throwing off less waste energy than a paddle, though I've never seen any data to prove it. Our dream CLC vessel would be easy to design so that the motor was always operating near max efficiency. Because? Because the designer can pretty much tell the owner "you WILL go this speed, all the time". 3 knots won't violate any traffic laws, and in contrast, the customer will rarely want to go any slower.
I have seen some data on the efficiency of the burrito-burner, but it is really hard to find a well-to-wheel analysis. The exception is when one finds a militant vegetarian. They invariably make the good point that eating pork chops is less energy-efficient than eating tofu.
Anyway, a megajoule of beans definitely ends up as less than half that at the throat of a Greenland paddle, whatever the precise number. So electric wins.
In Response to: Re: square sterned canoe by LeeG on Jan 17, 2006