Bottom Line Fish Finders 

& 

Cannon Downriggers!

Affordable electric downriggers like the Mini Mag and Magnum 10 (workhorse of the Great Lakes) make trolling with downriggers a pleasant experience.
Uni Troll Get the biggest bang for your buck! You get a downrigger with a low-profile swivel base and telescopic boom to boot, all in one package.
BottomLine fishfinders and depth finders utilize sidefinder technology allowing you to pinpoint fish below your boat and off to the side, at the same time.