Britannic drove her two wing shafts with triple-expansion steam engines and sent their exhaust steam to a low-pressure turbine on the center shaft. This hybrid arrangement delivered a stated top speed of about 23 knots, respectable for a vessel of her size but unexceptional beside contemporary warships. Merchant lines used speed as a public selling point, while navies benefited from concealing a ship's true performance. If an opponent knew the real maximum, it could design interceptors and plan around that ship's strategic and tactical maneuvering limits, so a published naval figure did not necessarily tell the whole story.
Notable Point · 21:10-24:11
Britannic's hybrid machinery and the meaning of published speed
Britannic's combination of reciprocating engines and an exhaust-steam turbine leads into a lesson about why merchant and naval speed figures served different purposes.