Trolling Motor shaft length?

I asked earlier about Spot Lock and have been shopping. I was comparing Power Drive to Terrova.

I have a choice of 45 or 54 inch shaft on a Terrova 55. I check my boat; from Bow to waterline is 20 inches; so I think I can be fine with 45 inch.

I kind of am thinking of getting 54 inch shaft anyway? Would it be better to err on side of having it longer; or better to get the 45" if that will do the job?

Get the longer shaft. Bought my first autopilot 20 years ago. Been on 4 different boats. Was still working fine, except for the autopilot, when I finally upgraded to a new one last year. You can adjust the length of the shaft up or down to suit your needs if you trade to a different boat.

Thank you. That is kind of what I was thinking.