Target depth chart in the Precision Trolling book?

So….I finally got the Precision Trolling book and I am trying to understand the Target Depth chart. Maybe I have not had enough coffee this morning……but I will walk through an example.

For a Rap SR-7: According to the depth curve for 10# mono it will take 68′ of line to reach 9′ depth. Now, if I look at the target depth chart for 10#/4# diameter Fireline and follow it down to 9′ it gives a dive curve depth of 7 ft. I assume this means to reach 9′ with 10/4 Fireline I should let out the amount of line for 7′ of the 10# mono curve….that would mean I would have to let 38′ of line to reach 9′ depth?

If the answer to that question is yes, then why does their dive curve for 10/4 not reflect that? At 38′ back the dive curve shows a running depth of around 7.5′ for 10/4 fireline.

I am not sure if it answers your question, but I know fireline with its less stretch and small diameter will dive faster. So it should make sense to let out less line. I don’t know the exact numbers.
Another thing I learned this past week at the Skeeter Boat trolling demonstration by Brad Juaire is that line counter reels only count out the number of revolutions of the reel and not the number of feet of line. Keep that in mind if you go that route, because you need to pre-measure the line by hand and compare it to the number of revolutions.
I would say that if you have any questions about trolling cranks, get in touch with Brad on here. He seemed like a really knowledgeable guy and all he does all Summer is pull cranks. Hopefully he sees this post and can help you out. Otherwise send him a PM. Good luck!

I’m not quite following your example above. My precision trolling book is in my boat which is still in storage. Walleye_Warrior is right in regard to using braided line – you don’t have to let out as much as mono due to the line density (typically it’s around 30% less but is depended upon the crankbait and the desired depth).

Remember that the book is just a guide and the formula is non-linear meaning it’s a depth curve rather than a sraight line. So if you get within the range you’ll be OK. I typically target fish 2-4 feet above the arcs on my sonar in poor water clarity and 3-6 feet above in clear water since walleyes like to feed in an upwards direction.

Time on the water will help tune in your depth curves. If there’s a particular crankbait that you really like – experiment with it. Find some long sand flats and let out line until you tick the bottom. Speed has a lot do with it and each crankbait is a little bit different.

Hope this helps

I guess I was just curious as to the exact data they have in their guide not seeming to make sense. The curve I see for 10/4 fireline does not match the target table numbers they say to use if your using something other than 10# mono.

I use powerpro on my linecounter setup and am comfortable with it and how it will run, I am just trying to make sense of the numbers/curves in the book and their recommendations on the table.

I mainly run #5 and #7 shad raps….and the #5 only has the mono dive curve so using the #’s on the target depth table and drawing my own line does not seem to match the #7 curve.

Maybe that table is for the max values, for lures with the steepest dive curves.

Exact depth curves for Braid vs Mono are not perfect.
Someone already mentioned the line counter reels are not exact either. ( depending on how full a spool is)
I’ve found that 10 mono vs 10 braid is about 10-15 % deeper with 10 pound braid. One sure way to know is find a clean sand flat and experiment.