Have you considered a 36 lb thrust Minn Kota @ $ 139.99 plus a 205 min
reserve capacity @ $ 65.oo? This combo would power your canoe for about 3 to
4 hrs @ full speed of about 7 mph. No fuel, no noise, no pollution (until
you dispose of it!).
I use such an animal on a 13' 300lb sailboat...
SF