One suggested reason for the Royal Navy's wartime boiler choices is the scope to demand additional output when necessary. Machinery already operating near the limits of its materials and systems has less room for that treatment. A boiler with a suitable margin can be pushed further, although doing so still increases wear and tear. Peacetime limits therefore remained relevant to wartime maintenance, even when an operational emergency justified adjusting them.
Notable Point · 1:31:18-1:32:44
Boiler safety margins allowed extra output at a cost
Driving boilers beyond normal operating limits depended on their engineering margin and increased machinery wear.