Be aware of the torque of electric motors. Most outboards are 2:0 to 1, or easy as that is half the rpm of gas. That changes the prop depending on hull, wetted surface, hull speed/waterline ratio etc. I typically reduce the pitch for electrics.
Thanks, Cal
Sent: Monday, September 08, 2014 9:10 PM
Subject: [Electric Boats] Re:New Member and question about displacement
Have been thinking about motor speed and gearing. Since I am not so concerned with attaining hull speed seems like running the motor up towards it's max at my fastest normal cruising speed and having a higher gear ratio would be the way to go. My prop calculations say that with a gear ratio of 2.5:1 I can run an 11 x 9 prop which I think should push the boat better at slower speeds. I think you also with the increase in gear ratio you get more torque at at the prop at lower amps at the motor(?) .
Probably the way to go is to use a lower end from a 20-30 hp motor to fit the larger prop size. Just does not seem like the little prop from a small motor would do the job.
I do want a generator at some point so probably will just spend the $$ for brushless.
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Posted by: "cal" <h20dragon@centurytel.net>
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