Last summer's project.
Old surfboard 24" x 14ft $50
Minn Kota 12v 30Lb thrust trolling motor from WalMart $99
Waterproof battery box (Walmart) $15
Some fiberglass and epoxy $15
It worked but was slow so we used it with 22V 6S 10,000mAh Lipo and it worked for a while before the internal controller( 5 speed resistive type) blew up.
Just opened it up and bypassed the internal controller (third pic) and it works great at 24V. The winding can handle 24V, it was the internal controller that was not upto the job.
Now using Sabretooth 2x32 PWM brushed motor controller which gives forward/reverse with PWM. https://www.dimensionengineering.com/pr ... rtooth2x32
A potensiometer in latex glove is used for throttle until I find waterproof throttle.
Top speed is about 5 mph.