Trolling can be very effective for targeting largemouth bass when they are deeper, however, the percentage of anglers that troll for bass is very small.  Find the deep water weed edges, deep points and shorelines with nice drop-offs and troll with your favorite medium depth and deep diving crankbaits and you should be able to catch some nice bass.
The summer and late fall are usually the best times to fish this way for largemouth bass.

line-3Trolling Tips for Largemouth Bass

Slow Trolling Deeper Water

A great technique for fishing deeper water is to use your trolling motor and slowly troll your baits.  Rig your favorite soft plastic bait on a Carolina rig or drop shot rig and slowly work the bait while staying vertical.  This is a technique that anglers use more for smallmouth bass, but it can pay off big time when largemouth bass go deep.

Trolling Deep Diving Crankbaits for Deep Water Bass

Trolling with deep diving crankbaits to target largemouth bass is a great technique for the summer through late fall.  At times, largemouth bass will be found very deep and to cover water faster, trolling can be a great technique.  Those bigger crankbaits can also be a pain to cast, so trolling is a nice way to present them without wearing yourself out.  Fish the quick drop-offs around shorelines, points and in the channels and you’ll probably find some largemouth bass willing to eat a crankbait.  Deep weed edges and offshore humps are also great places to troll for largemouth bass.