High-pressure boilers turn engineering into craft

The later H-class studies build on boilers that were already complicated in Bismarck and Tirpitz. Boiler control always involves experience and judgment, but the German systems demanded near-perfect operation inside a particularly narrow tolerance. Adding further individuality would make each installation depend more heavily on its chief engineer and crew. The comparison with HMS Warrior's era recalls a time when engines and boilers were unique machines operated as much by craft knowledge as standardized science.