On Sun, 10 Jun 2007 07:34:57 -0000, steve'smustang
wrote:

I've asked a couple of you already about not understanding how the
electric boat motor's power is changed into thrust or horsepower. I
have 12 foot fiberglass boat and want to buy an electric trolling
motor. But I haven't found any place that would explain what size,
which is the best suited for lake fishing.

To determine thrust and horsepower, a dynamometer is used along with a
set of equations that convert the readings to thrust and horsepower.
You don't really need all that to determine how much thrust you need
for your boat.

12 volt trolling motor will do just fine - you can get power ratings
from 30 to 55 lbs at 12 volts which would be good for a half day or so
fishing on a fully charged batters. For more battery life, use two
batteries wired parallel which, under most circumstances, will last
you most of the day. Remeber the higher the thrust, the more energy
drain on the battery.

I push around a 14 foot Princecraft with a 40 lb thrust motor loaded
with gear and me (boat, 25 Johnson, battery, gear and small cooler)
for a good 5 hours on smaller lakes. That size motor will do fine for
your boat.