Why cramped submarines slow construction and upkeep

Could Germany have made a fleet-submarine concept work before the Cold War?

Dönitz's preference for smaller boats constrained later designs; slightly larger hulls could have eased construction and maintenance.

Dönitz's preference for smaller submarines is linked to difficulties with the Type XXI and Type XXIII programmes. Tightly packed machinery demands more precision during construction and gives maintainers less room to work. A slightly larger hull can therefore be quicker to assemble despite requiring more material. Destroyer design presented the same trade-off, since better access around machinery can reduce manpower and maintenance burdens.