One of my favorite methods of fishing live baits in rivers and streams is to use a slip bobber. A slip bobber slides freely up and down the line. You control the depth of your bait by setting a bobber stop that is adjusted according to the depth of the water.
The idea is to have your bait near the bottom but not necessarily dragging the bottom. The fish are used to finding hellgrammite or crayfish near the bottom, not drifting near the surface. But a free-drifting hellgrammite or crayfish is not that unusual since they sometimes are swept off of the bottom and are at the mercy of the currents.
The baits you use will have a bearing on the size of smallmouth bass you are catching. On just about every river system, hellgrammites are present, and they will take lots of bass and other species as well. You could think of them as great bait for numbers, but not necessarily for size. Crayfish work better on some streams than others, and at certain times.
Minnows are universal bait, but not all minnows are equal in terms of production.
Another great bait is a big-creek chub. There are several species of chubs, with the best known being the species with the tiny horns on their heads. While you can also catch chubs with a seine, some of the best river fishermen I've met catch the chubs using small hooks and tiny pieces of worms. Good chubs are five inches or more in length, discouraging small bass from taking your offering.
Big chubs and madtom catfish (stonecats) are heavy enough to cast and you will not need any additional weight to cast them with the slip bobber. The chubs and madtoms will fight the bobber as they drift in the current, and the smallmouths will often crash them with aggressive strikes. This is the best method I know for taking very large (more than four pounds) river smallmouths in the summer.
Drifting live bait isn't the only way of catching river smallmouths in the summer, but it is the most consistent and productive.
Bill Anderson writes a weekly outdoors column for The Herald-Mail. He can be reached by e-mail at