otnmbrd wrote:

This becomes an engineering question and I'm not an engineer. However,
considering the mass involved, I'd assume that the process for reversing
engines running at full sea speeds (even recips) would involve a good
deal more than just "throwing a lever" G

Reversing only required pulling one lever to admit steam to the cylinder
of the "reversing engine" which in turn shifted the valve gear to bring
the correct eccentric into play.

Efficient running was something else entirely though, with adjustments
to the valve gear to set the desired "cutoff" of steam to balance
economy vs power.

Rick