Can a ship keep its original turbines and screws when small-tube boilers raise horsepower?
Short answerPossibly, if the original turbines were robust enough for the higher pressure; lightly built machinery would probably also need replacement.
NotesReplacing old boilers does not automatically deliver a safe speed increase. Heavy-duty, well-built turbines may accept higher steam pressure and make use of the extra output. Machinery designed to the minimum requirement may need replacement as well. Modernization depends on the hidden margins in the original plant as much as the component being upgraded.