What's the differance between the 12V and 24V trolling motor?  I'm guessing 24V are for the stronger Lb. thrust and the 12V is for th weaker.  Am I correct?

A 12 volt uses 1 battery

24 volt uses 2 batteries

36 volt used 3 batteries

yes, usually the higher pound thrust are in the higher volt motors

I think about 55# is the biggest 12volt you will find

82# is about the biggest 24 volt

and the 101 & 109's are 36 volts

However; there are some 24v in the low 50#"s

and some older 36volt motor that were around 80#