# Electric sternwheeler



## Mungo (May 31, 2013)

I know this is a bit off the electric car line, but it IS my new project, and I'd love some advice/input, etc. We're in the process of building a sternwheel pontoon boat, using a 6 foot, 8 bucket wheel and two 30 foot pontoons. I would love to electrically power the thing, using battery power for short hops and an electric generator and power supply for longer ones. The motor options, though, have me stumped. I would love to find a direct drive motor, something in the 5 horse range, that would be happy running in a one to sixty rpm range and happy with taking a reversing speed controller. Would love to have whatever input or information on ideas, models, etc, that the board has...


think cheap, we work for a living


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## major (Apr 4, 2008)

Mungo said:


> I know this is a bit off the electric car line, but it IS my new project, and I'd love some advice/input, etc. We're in the process of building a sternwheel pontoon boat, using a 6 foot, 8 bucket wheel and two 30 foot pontoons. I would love to electrically power the thing, using battery power for short hops and an electric generator and power supply for longer ones. The motor options, though, have me stumped. I would love to find a direct drive motor, something in the 5 horse range, that would be happy running in a one to sixty rpm range and happy with taking a reversing speed controller. Would love to have whatever input or information on ideas, models, etc, that the board has...
> 
> 
> think cheap, we work for a living


You have to gear the motor. 5hp at 1 RPM is 26,000 lb.ft. of torque. Will the shaft take that? A motor to put out that amount of torque would sink your boat. Even 5hp at 60 RPM is 438 lb.ft. That takes like a half ton motor to run continuously. So get a 5 hp motor running at a reasonable RPM like 1500 to 2500. If you're on the cheap, look for a used forklift drive motor in the 7 inch diameter size range. Use a speed control and belt or chain reduction(s) to get the speeds and speed range needed for the wheel.


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## kennybobby (Aug 10, 2012)

How much does the boat weigh empty, and loaded? What is the normal cruising speed and maximum speed you require? What is the size of your generator, and size of the battery pack?


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## Mungo (May 31, 2013)

thanks for all the advice: A little info: The boat will weigh around 3000 lbs. Being a pontoon vessel, it won't plane, so top speed will be limited in any case to around 8kt, 5 being more likely. The current genny we have is 3k, though that could certainly change. We've looked into a few options for easy propulsion. One is the use of automotive or marine winch motors: they're already geared to lower speeds and are rigged for exposure to the elements, and have been used successfully in a few paddle wheel experiments ( see http://youtu.be/RdSJ8LXqPp8). My only hesitation is with their duty cycle, which tends to be short (though such a motor would be pretty undertaxed in this application), and as to what kind of speed control could be used on this kind of (mostly) series wound motor. Another option is to go AC, using something like a drill press or router motor with a speed controller. Battery pack is, at the moment, an open question. The boat will have two deep cycle marine batteries to handle lighting and other needs, which could be used for short bursts of propulsion and steering, but I suspect anything more would have to come from a generator or generator/power supply combo.


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## Woodsmith (Jun 5, 2008)

You could use the small forklift motor, as major suggested, and mate it to an industrial worm and wheel reduction gearbox to get the ratio you need, something around 42:1 will reduce 2500rpm to about 60rpm.

A speed controller and reversing contactor will sort out the speed and direction of the paddle wheel.


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