FLAT water distance training? How far is far?

[adios pantalones]

Depending on the curves of the river you can even get reverse currents or eddys that propel you upstream, the same holds true in coastal channels and bay mouths, you can often capitalize on adverse tidal current by hugging the bank or jetty.

Yes, that's largely correct. The exception being right at the mouth I may move a little more away from the jetty. I prefer a little more room near surf and you have the potential for wonky currents at the mouth. Unless I clearly see a dominant current at the mouth, I give the rocks plenty of room.

So what is happening at the mouth of a harbor?  Faster current going in/out in the middle of the mouth, and less/slower current along the rock jetty?
So to get in/out of the harbor, you are hugging the rock jetty? 

thanks