And to think, those old ships had to be designed so that "wear and maintenance" items could go through those narrow paths and hatches to be periodically re-machined and repaired. Problems with larger items, such as gun turrets had to be repaired on site. A ship in wartime operations had a very long supply chain, and the importance of the shop grew. During peace time, often replacement parts were simply ordered and installed. Or to put it differently, give me a 24 hour video sequence of the shop, and I can tell you whether a ship is in a peacetime posture, or at war.