This post isn't about how to use your sonar unit, it's about how to use your sonar unit to locate active bass along with your other senses like eye sight, hearing and some common sense.
At the moment it's early fall transitioning to winter or the colder water period. Bass, largemouth, smallmouth and spotted bass are relocating, it's time to move.
I don't fish from shore, so I will talk about using a boat to locate bass. The big advantage a boat gives us is mobility, we can go everywhere on the water that is open to fishing. When I launch my boat the first thing I do is start the big engine and let it warm up, the next thing is put the trolling down, switch on the sonar unit and check the surface water temps. I do this year around, it's my routine.
The next things I do is look around for fish eating bird activity, under the docks at the marina for bass and baitfish, then making a wide slow circle around the launch ramp out into deeper water looking for how deep any basss or baitfish might be...surveying the marina to determine where the bass and baitfish located. Some days I don't leave the marina and catch bass there for hours.
Grebes, both western and pied billed are shad eating birds, cormorants and seagulls eat all types of fish, so look for fish eating bird activity, active birds equal active predator fish like bass.
My next move depends on the seasonal periods, generally I divide the lake into 3 parts; the lower end by the dam is the deeper water zone and good place to start during the winter or colder water periods. The middle section of the lake is good during transition periods like pre spawn and fall, the upper third for spawn and summer transition. The 3 lake zones are very general, but a starting place to continue my sonar survey. Big lakes with large creek arms are like individual lakes.
I like to survey major points starting at the base near shore and make a slow circle out into deeper water like the marina area and circle back along the opposite side of the point looking for signs of active bass or baitfish. If I meter them it tells a lot, if I don't see anything it tells the bass are somewhere else. If you meter the marina and major point without seeing any signs of bass or bait fish, the bass maybe tight to cover, so go check out the cover areas. To check out cover requires fishing in the cover.
Tom