The date of invention is separate from the point at which machinery can operate reliably in salt water aboard a warship. Surface-ship gearing is not treated as exotic, because historical steam plants already combined boilers, turbines, and reduction gears. An all-diesel plant removes the boiler and turbine stages while retaining the gearbox. The counterfactual investment is years of testing and refinement that raise engine power from Bremse's level toward Z51's, rather than the sudden invention of an unknown technology.
Notable Point · 42:31-46:23
Maturity and gearing matter more than first invention
The video distinguishes a technology's first appearance from the point at which it can be reliably operated in a saltwater warship.