Anglers unfamiliar with lead-core line should buy some and experiment, particularly at this time of year, when walleyes can be difficult to locate, as are smallmouth bass and northerns. A lot of information is online about how to fish lead-core line. But the basics are simple: You’ll need backing on the reel, and the line is colored differently every 10 yards, enabling the angler to know how much extends behind the boat. Also, a 20- to 50-foot fluorocarbon (or mono) leader is tied to the end, ahead of a crankbait. Trolling speed affects depth. Experimentation is necessary. But worth it.