Walt, I don't have a wealth of knowlege, but in fishing 45 or so hours last week in the james and a lifetime of river fishing in Ohio These are some casual observations. 1st, the tide, in my opinion just gives you more options. You now, depending upon tide fish both sides of humps, both sides of ledges, have differing current breaks and eddy's, and overal many more times of day when the fishing is or should be good somewhere in the system. Predatory fish feed when bait is vulnerable. When they are shallow the eaters foll the eathen. When current disorient them they become more susceptible to being eaten.
Pretend you are a baitfish. During an incoming tide you know the brute that wants to eat you is on that side of the structure. If you don't know this, you die. When the tide changes the brute changes sides. As a baitfish, you also are keenly aware of that fact also. Now, in times of transition, there is another period of vulnerability being if you the baitfish go around one side of the hump to switch and the brute goes to the same side as you it's goodbye you!
In an inland river at least the current is constant and goes in the same direction, thus is more predictable.
Like I said, it may be pure BS, but it sounds good.... :wink: