My first boat had cannon manuals, they worked because it's all I had, eventually later I got scotty electrics with my 2nd boat, I love em.
The fathom master manuals my uncle had on his boat weren't bad though! I liked those much more than the cannons.
I definitely don't miss cranking up every time I came off the clip.
A friend of mine showed me a cool trick, mainly for stacking on a slow troll for kokanee or sockeye. send your downrigger ball
down to where you want to fish with your first pole clipped in, on your second rod attach a shower ring, or a carabiner clip with a weight and a release attached to the clip, run that down your downrigger line till you hit your desired depth and your good. Gotta have a line counter reel though. Gets ya close. If you break off the ring just slides down your cable and stops on your downrigger ball. Pretty cool trick