Just curious as to the strength of flow of a river would dictate how heavy a line people will use. Does anyone change their mainline if fishing flooded rivers like the Trent for example. I have pondered this and can't decide if a heavier line would be better as more resistance to damage from river born small branches etc or stay on a standard line.
There is also the extra factor of hooking a barbel and it turning sideways in the current downstream to contend with, so not only the fight in the fish, but the extra 'weight' caused by the current.
The opposite sometimes Kev, alot of emphasis placed on lines and their thickness and subsequent increase in drag from the flow. Tbh Barbelling is the only branch of my angling where i pay attention to line diameter, getting the thinnest for highest bs at 10lb i can get mainline wise. Decent chapter on lines in one of the books i recommend, whereby some weren't/aren't actually round in section, a non round line giving more drag potentially.