Looking into getting new trolling motor. How do I tell how what size shaft length is best for my 19ft boat. The trolling motor shaft I have now is roughly 45 in long..So should I just go with another 45in long shaft length?

Are you fine with the performance you are getting from the current 45" shaft? Most dealers early on were placing 45" shaft trolling motors on all boats. As of late with all of the upgrades, most have been changing over to the 52" shaft.

Dies your boat sit nose high in water due to bigger motor, jackplate,shallow water anchors & brackets, 4 batteries all added in back of boat. If you fish offshore/deeper water, then yes, you'll want to consider a 52" length. On windy days you'll appreciate it. Spot lock cant hold as well if prop is cavitating from rise on waves. I fugure you're wanting the spot lock feature. If your boat sits level then its not as critical.

Thanks for all the good info..Just what I was looking for.

If 45 works, do it. I went from 52-45 on my Ultrex and its fine.
ZX21

Which boat do you have and what trolling motor are you looking at. Just because it's a "45" doesn't mean it's 45" shaft -- but it's close. Even MinnKota measures shafts differently. For instance, the 45" on an Ultrex is 48" long, however there is a 3" depth collar above the steering module that gives 45" of usable shaft when measured all the way down from the top of the steering housing to the top of the lower unit. The Fortrex 45" and the Maxxum 42" both use a shaft that is 43.75" long. Call me if I can help.
John