Phoyem,
How long and what kind of lead do you run with your leadcore?
I troll leadcore slightly different and I catch alot of walleyes trolling with it also. There are many ways to troll with leadcore and it boils down to what one gets used to and learns to use.
I started trolling leadcore years ago with regular 18 lb. dacron leadcore and still use either the Mason or the Sufix Performance that both sink in the neighborhood of 5 feet/color at 2 mph. I troll leadcore with 10.5 ft. rods and use leads of about 8 feet of 15 lb. Power Pro on each, attached to the leadcore by small barrel swivels that will almost eliminate line twist if a crank becomes fouled which happens. The barrel swivels are small enough to go through the rod eyelets if someone makes a mistake and reels in too much line when reeling line in. Many cranks like to spin when they get fouled and twisted leadcore is a PIA.
Anyway, I just estimate approximately how deep a crank will run trolled with eight feet of 15 lb. Power Pro and just subtract that depth from the total depth. As a rule of thumb, the depth that most cranks run when trolled behind 8 ft. of 15 lb. Power Pro is pretty similar so I generally just estimate 2 ft. for all of the cranks that I troll. The walleyes have never seemed to mind.
In your example, I’m curious how you get a 10 ft. diving depth for a #7 Shad Rap. I’m not Not saying you’re wrong, I’m just curious how you calculated it.
This is how I run leadcore and have been or years. If I want to get a #7 Shad Rap to 24 ft. I estimate that 8 ft. of 15 lb. Power Pro will get a #7 Shad Rap down about 2 feet. I subtract that from 24 ft. so I need my leadcore to get the Shad Rap down another 22 ft.. At 5 ft./color, I need 132 feet of leadcore to get down 22 ft. and adding that to the leader, I’m down to 24 ft..
Some guys will tell you that your leader has to be fluoro or you need the stretch of a mono leader or you will lose fish but the rod also plays an important part in the whole thing. I’ve honestly never had an issue catching fish of keeping fish on once they are caught.
The depth that cranks run may vary slightly from where you think they are running but you know for certain that if you are banging bottom, they are too deep. If that happens just reel up a couple of turns and if you start catching walleyes, make a mental note of the number on your line counter and keep repeating it. There are days when walleyes prefer coming up from several feet to eat a crank and like them higher.
My wife and I troll cranks using snapweights at the same time that we troll cranks with leadcore wherever more than one rod/angler is legal and usually point our LiveScope transducer back to watch one of the snapweight cranks to see how walleyes are reacting. One thing that I have learned from it is that is that walleyes will go up quite a ways to get a crank most of the time. Many times they will swim all the way up to inspect a snapweight. I’d much rather err on the shallow side than run cranks too deep.
It all takes experimentation.