Line up a vehicle on either side of the private canal to be treated. Connect a number of heavy chains together so they form a net. Run a long chain from one vehicle to the other and connect the ends to both vehicles. Spread out the chain net in the water.
Turn on the vehicles with the coordination of a second partner. Begin driving forward parallel to the canal, dragging the chain net in the canal behind both cars. Drive slowly but with enough speed to move the heavy chain forward to break the weed stalks in the water.
Repeat the process until a significant amount of weed growth has been broken up. Take a raft and rakes and enter the canal water. Clear out the weed debris created by the chain process and toss it out of the canal to dry up and wither.