Why might navies accept electric-drive inefficiency?
Short answerQuieter, more flexible propulsion can provide operational advantages, especially for mine warfare and other specialist roles.
NotesHMS Belfast's separate low- and high-speed turbine arrangements show why machinery is optimized around an operating profile. A turbine designed for full power can be inefficient when forced to spend most of its time at low output, so ships may carry different machinery for different speed ranges. Electric transmission adds conversion losses between generator, motor, and propeller, but podded propulsion and flexible distribution can offset those disadvantages operationally. Motors can run quietly and place power-producing equipment away from a single shaft line. Hydrogen fuel cells could distribute generation still further and reduce the acoustic signature. Those qualities are especially valuable in mine warfare, where avoiding detection or influence mines may matter more than obtaining the lowest fuel cost.