The first CODAG warship remains uncertain

What was the first warship or destroyer class to use combined diesel-and-gas propulsion?

The first example is uncertain. German frigate work is recalled, but no ship is confidently identified as the first.

The first combined diesel-and-gas warship is not identified with confidence. German frigate development is recalled, but priority is uncertain. A possible Royal Navy example is suggested and then doubted, so the exchange leaves the first application unresolved.