How, When, and Where?
How:
I wont go into what rod, reel, and line you should or shouldnt use but instead simply list what I use. Personal preference trumps all else so fish what you are comfortable with.
My rod is a Med Heavy American Rodsmiths David Fritts Cranking Rod - 7' long
My reel is a Shimano Curado E5
My line is Trilene 8lb XT (yes, 8lb, its tougher than you would expect)
My presentation is simple, plow the bottom with the bill and run into everything I can. Pause a second after running into solid objects before starting the retrieve again.
When:
Anytime. Just as some bass stay shallow year round, some bass will stay deep year round. However, late fall/winter and just before the dog days of summer are when I'll start really looking for fish gathering deep. Once the thermocline sets up, Ill fish fish the maximum depth of the thermocline plus an additional 2-3 feet deeper. There will be fish below the thermocline, just not many. I assume they are down there feeding for breif periods then find their way back above the thermocline, but I honestly don't know.
Where:
This is the challenging part for me sometimes. Some days I will search and never find them. Other days I will search for an hour only to find them in one spot that appears identical to others that I have already checked, and they will be stacked THICK. Once found, you can usually sit on them and make a good trip out of it. Specifically, I look for channel swings with steep drop offs on either side of the channel. Ill usually fish the edges of the dropoffs but will sometimes hit the bottom of the channel for a while. The second place I look for is mid lake humps. Much like channel swings, when I find them they are stacked thick and you can make a good trip out of a single location.