Why the Royal Navy favored 300 psi boilers

The Royal Navy standardized on a roughly 300 psi Admiralty three-drum boiler from the late 1920s. That conservative choice reflected the demands of supporting ships across the Atlantic, Mediterranean, Indian Ocean, and Pacific, where machinery had to remain dependable and repairable far from Britain's industrial base. The design sacrificed some performance potential in exchange for a known system that the fleet and its support network could sustain globally. Reliability across that worldwide support network was an institutional and logistical priority, even at the cost of higher performance.