Infrastructure limits on naval expansion

How often do naval counterfactuals ignore the infrastructure needed for a rapid fleet buildup?

Very often; German H-class and Plan Z scenarios commonly assume commissioned slips, machinery plants, labor shifts, and worked-up ships existed when much of that capacity was unfinished or only ready on paper.

Nazi announcements frequently treated slipways or ships as commissioned before construction work, trials, and crew work-up were complete. A credible buildup must ask whether yards can produce machinery, whether factories and skilled labor exist, and whether multiple shifts actually operate. Treating paper capacity as immediate output makes Plan Z and H-class counterfactuals expand far faster than the historical industrial system could support.