MT, I like to use line counters when deep trolling cranks.

A line counter reel allows you to more precisely set out diving lures in pre-determined patterns (amount of line behind the boat allowing lure to reach desired depths) and duplicate successful set-ups to more effectively fine tune a productive trolling pattern for the day.

A LC takes all the guess work out of precision depth trolling.

I have only taken my old Daiwa Sealine Line counter reel  a couple of times to Quetico. While it worked well ... it was just too heavy to lug around. It weighs 15.7 oz. I usually use it with a rod holder when fishing out of a boat with a motor and not a canoe.

Daiwa has come out with a newer, lighter weight  Sealine B model SG17LC3B that comes in at 12.9 oz. and holds 250 lbs/12 lb test.   The new Shimano Tekota 300LC  comes in a bit heavier @ 14.3 oz and holds 220 yds/14 lb test ... I really like Shimano reels. The lightest line counter I have found is the Ambassadeur 5500 LC 11.3 oz. 205 yds /12 lb test.

MT is right on ....  with a Line Counter you can find the right lure and the right depth to run it at and then duplicate the pattern to more effectively produce bites.