Why navies were slow to adopt marine diesels

Why was naval adoption of marine diesel engines so slow?

Steam turbines delivered high power through a familiar, widely adopted system, while diesel required navies to invest in a different path that competitors were not yet following.

Steam turbines offered a familiar route to the high power needed for fast warships. Navies and shipbuilders already had established experience, suppliers, and performance comparisons for that machinery. Diesel systems therefore had to overcome both a technical disadvantage at the highest power levels and the conservatism created by an existing industry standard. Competitive regimes also wanted to beat rivals at the same game, which made an unconventional propulsion choice less attractive even when it offered range advantages.