well if your looking for cats on big water such as the Ohio river ... you will want to look away from the banks .. i only look to the banks to see what type of structure its made of ... chunk rock , gravel, mud , mussel beds , etc... what you see on the bank is usually whats under the water also.
lets take chunk rock for instance,,more than likely the river bottom will be scattered with chunk rock and ledges or drops which cats relate to alot..
i will position my boat at least 50-100 yards from the bank and fish in 35-40 foot of water ,, my magic # is 35 foot . scatter your baits and fish , if you don't get bit in 30 min , pull up your anchor and move down 50 yards and try it again keeping your bait in the scent trail. you should hook up with one,
channel bends is another good spot to target fish, again keeping your baits at 30-40 foot of water..
now spring and early summer you can fish a little shallower but always keep one bait deep, as the summer water starts cooling down in the fall. you can also go bit shallower too
but again 35 ft has always been my magic number
hope this helps you some
steve