A ship may be flown briefly by four people, but that does not make four a viable operational complement. Continuous bridge and engineering watches require reliefs, overlap, sleep, and resilience when someone becomes unavailable, pushing even the bare minimum closer to eight. The distinction is between emergency control and sustained operation, not between manual and automated systems. Even a highly automated ship needs enough qualified people to cover essential stations without exhausting the crew.
Notable Point · 14:48-16:10
Watchstanding makes a four-person crew unrealistic
A four-person emergency bridge team is distinguished from the larger crew needed to sustain engineering and command watches around the clock.