Why were the French early adopters of forced-circulation boilers in capital ships when the basic technology existed earlier?
Short answerReliability and integration matter as well as the existence of a concept; supporting machinery must fit and its power demand adds further weight and space.
NotesThe question contrasts Richelieu's Sural boilers with earlier availability of the forced-circulation concept. Reliability is offered as one reason other navies concentrated on higher steam pressures instead. The discussion then shifts between forced circulation and forced-air equipment while considering how supporting machinery must fit inside protected spaces. An illustrative 100-kilowatt load would require larger generators, wiring, and more machinery volume. Mechanically driven equipment would likewise need an engine or turbine, so a seemingly simple addition can accumulate weight and complexity.