Me (see above) -- The lower river meandered all over the place every spring flood. Once it calmed down a tad one could actually drift upstream on the back eddies by crossing from bank-to-bank to keep on the inside of the 'ox bows.' Regardless, that was where all the upstream bushwhacking, cordelling, poling, rowing, sailing &c&c happened. Not head-on against the mainstream.

1834 UK take:
“THE TIDE OR CURRENT.
In river-rowing, when the tide or current is with the rower, a learner should in general take the middle of the stream. In rowing with the tide, however, water-men generally cut off the points, in order to keep a straight course.

When when the tide or current is against the rower, he should take the sides, preferring that side on which, owing to the course of the river, the current is least.––As there is an eddy under the points, watermen generally, when rounding them, shoot the water to the next point, and so on.” [p.78]

Dover-to-Dunkirk:
“SEA ROWING
...The distances run in this way are very great. We have known four men, in a short galley, row thirty miles in four hours, namely, from Dover to eight miles below Calais, or abreast of Gravelines, on the opposite coast.” [p.81]
[British Manly Exercises, Walker, 1834]