Why riverine warfare reverses familiar naval assumptions

River flotillas protect trade and infrastructure along routes whose course an enemy already knows. A battery covering a bend can halt traffic, which explains the inclusion of mobile artillery in Soviet river forces and the importance of shore positions in the American Civil War. A deep enough channel and a suitable hull can carry heavier firepower than a land vehicle. The channel nevertheless limits how many vessels can deploy and manoeuvre together. Dispersal and large numbers offer less benefit in those confined spaces, strengthening the case for a few well-protected vessels with enough firepower to suppress shore guns. Such craft must expect to take hits while forcing a passage.