What kind of fishing do you do and for how long. I have a 17.5 wareagle and run a 55 12 volt Terrova wired on 2 group 27 batteries like Mr dox said. Long lining or spider rigging I van run all day. Pump it up to 1.5 pull g cranks it lasts about 5-6 yours. I pull cranks with big motor. 54 shaft is plenty long for your boat.