Bottom Line Fish Finders 

& 

Cannon Downriggers!

If your looking for a downrigger, Cannon has a model for you.
Affordable electric downriggers like the Mini Mag and Magnum 10 (workhorse of the Great Lakes) make trolling with downriggers a pleasant experience.
Bottom Lines portable Fishin' Buddy 1200 and Fishing Buddy 2500 mount easily to a dingy, fishing tube, or a dock.  There Tournament 4300, Tournament 5300 and the Tournament 6500 are some of the most sophisticated fish finders in the world.