Why diesel-to-gas differs from steam's earlier transition

Does the shift from diesel to gas turbines mirror the earlier shift from triple-expansion engines to turbines?

Both involve greater power density, but fuel efficiency, cost, transmission choices, and safe operating limits make the comparison imperfect.

Both propulsion transitions offer greater power density. Early direct-drive steam turbines were fuel inefficient, while geared turbines made the advantage over triple-expansion machinery much clearer. Moving from diesel to gas turbines also increases power density, but brings higher cost and choices between mechanical and electric transmission. A diesel can run near its limit without the severe ship vibration associated here with pushing triple-expansion machinery, although sustained maximum output still wears it out. Diesels therefore retain useful naval roles even where gas turbines offer more power in a given space.