Trolling motor prop question

[Gimmyabeer]

Hello,
I have an older, bow mount Motor Guide trolling motor. I was curious if I replaced the two blade prop for a three blade prop, would it increase the performance.
I apologize if this is a stupid question, but it just popped into my head.
Thanks

 

[Silvertip]

Re: Trolling motor prop question

It has the same effect as changing an outboard prop without understanding the dynmics of what a prop does. The most efficient prop is a one blade but that obviously creates some issues with balance and other factors. When you say "increase performance" that means various things. 1) faster? 2) Battery last longer? 3) quieter?? (See where this goes???) But to answer your question you need to understand that the prop installed on a troller is chosen by "design" so that the motor consumes the least amount of current while providing a reasonable amount of "thrust). Remember, batteries have a limited amount current they can supply over a given amount of time. Put too much prop on the motor and the motor may push the boat qjickly but the prop requires that the motor draw more current so the batteriy dishcarges much more quickly. Besides, why the interest in "speed" since you are after all -- "trolling". Consequently adding a three blade prop with the same pitch as the two blade increases the "load" on the motor and hence the current draw. Adding a three blade prop with less pitch than you had originally doesn't gain any speed since with less pitch the boat moves forward less with each revolution of the prop. Lastly, if the motor you have would "perform better" with a three blade, four blade, or five blade prop the manufacturer would have installed one in the first place. They've done the research and testing for you (over and over I might add).

 

[Texasmark]

Re: Trolling motor prop question

Slightly off topic, but I bought a Minnkota back in '89 that ran a very large diameter 2 blade prop...like 10" or so...don't remember the exact number. I figured that the diameter would figure into some super torque for working the TM. Problem was, the dia posed a tremendous load on the motor and was very slow to respond to commands. The MG with a 4 blade, 2" roughly bladed prop, could outperform it because it could rev up much faster.

Be careful what you ask for, you just might get it.

HTH,
Mark