Tom Kirkman wrote:
10 to 11 MPH on a kayak with a trolling motor is suspect.
The reason you won't get a speed increase with a more powerful motor is that the pitch on trolling motor props doesn't require much power to spin under the weight of a kayak. A more powerful motor isn't going to spin the prop any faster than a lowered powered motor.
Now if you had a situation where the vessel you were propelling put the motor under a heavy load and it wasn't able to spin the prop very fast, a more powerful motor would indeed get you more speed as the RPMs of the prop would increase. But most kayaks simply don't tax most trolling motors. The only way we were able to obtain a higher speed was by swapping the common trolling motor props for small RC aircraft propellors. We also tried the prop from a Native pedal drive kayak as it has much, much greater pitch than standard trolling motor props. But it ate battery life very, very quickly.
But don't take my word for it. Play around and see what you can do.
I think I am going to be building out my own Lifepo4 battery pack. Looking for good cells on alibaba now! Will keep everyone updated on which way I go. Thanks!