Folks:
Over in the Navalism sim, my nation (Gran Colombia) currently occupies the upper Amazon, with a modest port at historical Manaus, Brazil. That far up the river, the Amazon's still a few kilometres wide and can handle ships with drafts of less than five metres. Gran Colombia has deployed two small protected cruisers, four torpedo-boat destroyers, and some lesser gunboats into the river, with several requisitioned auxiliaries in support.
The focus of Gran Colombian activity is supplying and supporting a land campaign, using the watershed as a highway system and denying it to the enemy, a city-state north of the river. Logistics are a significant issue, as the region is (apart from the enemy city-state) pretty much untamed rain forest.
It's very possible that Gran Colombia will soon find itself warring with the resident superpower, France, for control of this area. My question to y'all is: how would you foresee naval combat on the Amazon taking place with 1904-ish technology and equipment?