Canal Fishing with BulletBobbers and DualFins is productive by walking very slowly to troll in a zigzag style or a straight parallel path.
How to Fish Canals
Cast out perpendicular and walk about 10 yards to get the slack out of the line. You will have the best possible control if the line is not sagging in the water. All you need to do is keep an eye on it for a while and you will learn the feel for how much tension to keep on the line, how slow to walk and how to flip direction. You will find there is a speed for just running parallel and a much slower speed for zigzagging. It is easier with long light medium action rod but it won't take long to get the feel with any rod or no rod. Remember you are the predator but trying to catch fish that are behind you takes stealth. Slow and Stealthy is BEST.
This is basically the same as how you would fish any shoreline without walking obstructions. The path is often higher or 10 yards from the shoreline but that is a plus for this trolling technique because you are not scaring the fish out from the shore as you walk. The further you can get from the shore the better! Many towpaths like the Ohio Erie towpath are open for trolling long distances.