Why warships rarely carried two paddle wheels per side

Did military paddle steamers use two wheels on each side?

Rarely; extra wheels complicated water flow and took away broadside gun space, so one larger wheel was usually preferred.

Multiple wheels could interfere with one another's flow and required additional machinery. More importantly for gun-era warships, every paddle box displaced broadside weapons. Naval designers therefore tended to enlarge a single wheel rather than multiply wheels along the hull. The answer illustrates how propulsion arrangements competed directly with armament for scarce hull length.