The early ships were designed for seaworthiness in rough conditions. Fine hull shaping required more specialised work in forming and assembling the metal. That choice restricted how readily the ships could be mass-produced. Etorofu improved on Shimushu, with 14 ships completed and further orders redirected into subsequent designs. Later changes aimed to standardise hull forms and reduce construction difficulty. Repeated returns to complicated designs frustrated those attempts at simplification.
Notable Point · 12:29-14:30
Rough-sea hulls and the cost of complicated shapes
Hulls shaped for heavy seas required specialist work, prompting repeated efforts to simplify later kaibōkan for mass production.