Due to the high cost of the store bought "mallard machine", I decided to build
my own. I started with a 10 foot stick of
metalized conduit, bent it with a tube bender in a rectangle approximately 2
foot by 3 foot, then joined the ends with a conduit connector.
I then bolted another small piece of conduit about one third of the way down the long part of the rectangle, in order to have a place to secure the trolling motor shaft. I used a 1 1/2" conduit "U" strap to connect the trolling motor shaft to the cross piece. As you can see, I had to put some tape on the motor shaft to get a tight fit.
To make the motor shaft align properly with the frame, I had to bolt a small scrap of conduit to the top of the frame. I secured the top of the shaft with another 1 1/2" conduit strap.
In each corner of the frame, I put a small eyebolt to secure the floats (decoys). You will have to use a decoy with a hole in each end of the keel. Drop two lines, with swivels on the bottom, from the decoy keel and attach the swivels to the two eyebolts on the end of the frame. Adjust the length of the lines to get the proper depth for the trolling motor.
I bought the trolling motor at a yard/garage sale for 15 bucks. It was a MinnKota with a whopping 17 lbs. of thrust! I took the control head off the shaft, and was left with 4 wires running up from the motor (black, red, yellow and green). I connected a 10 ft. length of lamp cord to the black and red wires, stuffed the ends of all the wires down the shaft as far as I could, then caulked the living crap out of it with silicon. I put male spade connectors on the lead, and female connectors on the wire that runs back to the blind.
The only change that I would make to my machine is, I would use heavier wire.
Probably a 12 or even 10 gauge wouldn't be to big.
The purpose of the 10 ft. lead coming from the motor shaft is, you need to get
your connection from the lead wire to the wire running back to your boat or
blind above the water line.
If there is a little vegetation growing nearby, you can zip-ty your connection
there. If you are hunting open water where this is not an option, you could make
the connection on the
decoys back or around its neck.