George- I have the builders print for the C.S.S. Columbus' engines and drive gear before me as I type. This powertrain design was by the same set of people as did the C.S.S. Arkansas work.

I'm looking at clutches just aft of bevel gear that takes engine power from a cross-shaft between the two engine cylinders. The clutches are on the propeller shaft. There does not appear to be any means to run the engine on one cylinder alone. Two blade propeller in the drawing.