Shinshu Maru is proposed as a purpose-built amphibious-warfare vessel, while Type XXI marks the shift from a surface vessel that could dive toward a submarine intended to operate primarily submerged. USS Ticonderoga or Bunker Hill is suggested for the Aegis and vertical-launch combination. Narwhal represents double-hull submarine development, while Nautilus is another obvious candidate. Almost any ship can support a useful focused study when its design reveals a development, mission, or institutional change. Together, these suggestions map possible amphibious, submarine, and combat-system branches for the series.
Chapter · 8:12-9:41
What makes an amphibious, submarine, or Aegis ship pivotal?
Suggestions from Shinshu Maru to Type XXI, Aegis cruisers, Narwhal, and Nautilus show that key-ship status comes from the development or mission a vessel can explain.