Sultana, USS Cairo, and Civil War river power

Sultana represents the vast transport system that moved troops and supplies along American rivers, as well as the deadly consequences of overloading and boiler failure. USS Cairo represents the armored combat extreme: an enclosed stern wheel, heavy mixed battery, shallow draft, and iron-over-wood protection. Her angled cast-iron cylinders and 72-inch stroke delivered considerable torque and power. An auxiliary engine drove pumps that drew boiler feed water directly from the river, tying the machinery to its operating environment. The City class were river powerhouses, and their suitability for confined waters makes comparisons with ocean ironclads more revealing than simple prestige-ship matchups.