Electric motors and battery combinations...>>>

I'm looking for information about electric motors and the most efficient
battery combinations in terms of weight of adding a battery vs. the power
that going to 24volt might give me. I live in an area that doesn't allow
gas motors on its reservoirs; only electric motors, so I could only power my
12' jon boat with electric. I'd like to match up the most efficient
combination of motor size, battery, and weight. I would like to know if I
get longer run time and/or more power with a 50lb 12volt motor or a similar
sized 24volt motor? Or, would I get a better weight-power-endurance
combination getting a 36volt, 100+ lb motor??

Also, would I get more run time from 2 batteries (1 to run, and one as a
spare, i.e., "refuel") with a 12volt motor, or 2 batteries running
simultaneously on a 24volt motor?

questions, questions, questions...

--
Marty S.
Baltimore, MD USA