Are you running 12v,24v or 36v?I have an older champion 16' and recently switched trolling motors.I had a motorguide 48# 12 volt and went to a minkota 80# 24volt.What difference!I would say to get the biggest motor you can afford.you can never have too much thrust and if ya fish the delta alot like me then it realy comes in handy:-)
Try and give j luis a call.He hooked me up with mine and will give you excelent info.
Swampy