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This week's Feature Blog

Calibrating Line Counter Reels

By: Mark Romanack

The Precision Trolling Data phone app publishes critically important “Dive Curve” data based on testing conducted with very specific line diameters, trolling lead lengths and trolling speeds. No other source comes close to providing trollers with critical data that can be easily replicated again and again.

​ With the spring walleye trolling bite about to kick in full thrust, this is the perfect time to talk about the concept of “calibrating” a line counter trolling reel. Those who believe that “calibrating” is unnecessary and that “close is good enough” when it comes to monitoring and replicating your trolling leads, clearly don’t understand the dynamics that trolling leads plays on the diving depth of popular crankbaits and other trolling gear.

​ Varying the line out or trolling lead even just a few feet can and does impact dramatically on how deep that particular lure is diving. Just as important, the angler who ignores the value of calibrating his trolling reels is fishing with four, six, eight or more reels that all have a different amount of line on them and all will read differently on the line counter. In this case, it’s virtually impossible to replicate a productive lead length with other trolling rod/reel set ups in the boat.

​ Successful trolling is all about figuring out what are the most productive lead lengths and then replicating those lead lengths precisely to maximize trolling success.


​ In effect, anglers who don’t calibrate their reels are fishing blind in that they have no practical means of determining how deep their trolling gear is fishing. While it’s not necessary to hit fish on the head to catch them, the ability to put your gear close to, but not below fish that are found using modern sonar is hugely important.

​ The only other way to determine which lead lengths are the most productive is to experiment widely with trolling leads until a pattern starts to emerge. This process is time consuming, especially considering that with phone apps like Precision Trolling Data, it’s easy to deploy just the right amount of line to get your baits diving exactly where they need to be in the water column.

​ Knowing this, why would anyone opt to fish “old school” when we have the technology to control precisely where our gear is running in the water column?


​ Line counter reels are factory calibrated, but unfortunately they are calibrated using just one line diameter which in most cases is 20 pound test line. When other line diameters are used, the reel calibration is impacted because mechanical line counter reels function by predicting how much line will play off the reel spool for each rotation of the spool.

​ When thinner diameter lines are used, more line is loaded onto the reel compared to the line used in factory calibration. So each time the reel spool rotates, it lets out a different amount of line than the reel was calibrated at the factory to deploy and record with the mechanical line counter.

​ Simply stated, a trolling reel is calibrated when just the right amount of line is loaded onto the reel that when the line counter reads a certain number, that’s exactly how much line has been played off the reel. By adding or removing line on the reel and then measuring lead lengths against known distances, it’s possible to calibrate a reel so it delivers precise lead lengths time and time again.

​ The best way to calibrate a trolling reel is by first measuring off a set distance and marking that distance by driving two stakes in the ground. A distance of 100 feet is ideal because this is roughly in the middle of common lead lengths used by serious trollers.

​ With a known distance (100 feet) as a reference point, simply attach the line to one stake using a planer board line release, zero out the line counter, open the reel bail and then walk to the other stake. When the rod tip is at the second stake, the line counter should read 100 feet if the reel is calibrated.

​ Typically the line counter is going to read a number that is less than or more than 100 indicating that either too much or too little line has been spooled onto the reel. If the line counter reads a number less than 100, then the reel has too much line spooled on and line must be removed from the reel. If the line counter reads a number larger than 100 the reel is under spooled and line must be spooled onto the reel.

Mark Romanack is the founder of the Precision Trolling Data phone app. Romanack’s work popularized the need to calibrate line counter reels so they deliver the most accurate data possible. The key to being a more successful troller is to monitor details like lead length carefully and then to replicate productive lead lengths again and again.


​ The best way to calibrate a trolling reel is to fill the reel using a bulk spool of line until the reel spool to just below capacity. Don’t cut the line from the spool as it may be necessary to add or remove line from the reel.

​ Attach the line near the rod tip to one of the stakes, zero out the line counter and walk away to the second stake. When you reach the second stake look at the line counter. The line counter should read 100 if you have measured off 100 feet as your reference measurement. Again, if the number on the counter is less than 100 the reel has too much line on the spool. If the line counter reads greater than 100, the reel doesn’t have enough line on the spool.


​ A trolling reel can be calibrated using any line type or line diameter. Since most line counter reels are factory calibrated for 20 pound test line, any line larger or smaller in diameter than 20 pound test is going to change how the mechanical line counter reads. This is why a walleye angler who loads his reels with 10 pound test is not experiencing a reel that is closely calibrated simply by filling the reel to capacity.


​ Any brand of line counter reel can be calibrated using the directions here. Anglers who have a few of these and a few of those can still calibrate their reels effectively.

​ The thing to avoid when buying line counter reels are those with very small line capacities such as the 15, 17 or 100 size reels. All of these smaller reels have such limited line capacity they are not capable of replicating lead lengths accurately, especially when longer trolling leads are required.

​ The mechanical line counter used on all trolling reels is based on how much line plays off the reel for each rotation of the spool. When the reel only holds a modest amount of line, the diameter of the spool changes rapidly and the amount of line played off the reel spool becomes less with each rotation of the spool.

​ This is why small line counter reels are a poor choice for serious trolling applications. While many anglers love the smaller and lighter trolling reels, they are handicapping themselves with reels that do not replicate lead lengths accurately. The size 20, 30, 40 and 50 class reels are the best investment for most trolling applications.


​ Trolling is about paying attention to details and then replicating what works again and again. The only practical way to accurately replicate trolling leads is to take the time to calibrate each and every line counter reel on the boat. Not counting the time to spool line onto the reel, the calibration process takes about five minutes per rod/reel. This is time well spent for anyone who takes their time on the water seriously.


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