Rivers are often described as having a 'head of navigation', the furthest upstream point you can reach in a ship coming from the sea. Does this equally apply, regardless of propulsion method?
In particular, thinking about sailing boats, even small ones, it seems to me they might need more width on a river to be able to tack, or just generally respond to changing wind conditions?
I have seen it claimed that one of the reasons for the historical shift from ocean transport by sailing to steamship was because sailing ships had difficulty in the Suez Canal for that reason. Though that was large ships, and here I'm just thinking about small boats, suitable for operation by one or two people.
Do small sailing boats actually have more difficulty going upriver, than motorboats of the same size?