Replacing engines without addressing hull distortion or fatigue can transfer new stresses into an older structure. Rafted machinery may reduce radiated noise for anti-submarine warfare, while its mounting can also manage the physical forces generated by powerful engines and shafts. The same problem shaped 1930s battleship modernizations, when British, American, Japanese, and Italian planners had to fit modern machinery into hulls designed for earlier engines. A successful upgrade treats propulsion and structure as one engineering problem.
Chapter · 11:35-13:27
New machinery can expose an old hull's limits
See why a propulsion refit is not a simple engine swap: vibration, mounting, and hull strength must all be considered together.