Maintainability should shape a warship before equipment is fitted

What lesson should a new marine engineer and naval architect take from these videos?

Design for necessity and access: maintainable equipment and usable working space reduce labour, complexity, and crew requirements.

Each system needs a clear purpose and enough surrounding space for technicians to reach and service it. A slightly larger hull can reduce maintenance labour because crews can move around machinery instead of working through cramped openings or relying on helpers. Henderson made this argument to Chatfield during the interwar debate over larger destroyers: a larger ship could require fewer crew if it was easier to maintain. A passage two feet wide and only 16 to 18 inches high forces people to drag themselves through, whereas increasing its height to 30 inches lets them crawl on hands and knees and move much faster. Access panels need room to open as well as room for a technician to reach them. A hinged panel wider than its passageway defeats the purpose, leaving a choice between a wider passage, removable panels, or a special double-hinged cover.