Japan combined 14-inch guns with about 27.5 knots and protection intended to match or exceed other battlecruisers. The preference for a heavier hit is linked to Japanese military experience, including the Battle of Tsushima, and put first-generation battlecruisers with 12-inch guns at a severe disadvantage once within range. The discussion attributes Britain's 13.5-inch choice to logistics but does not specify the supply mechanism. Kongo's 36 Yarrow boilers produced 64,000 shaft horsepower, while Queen Mary needed six more boilers and 70,000 horsepower for only about half a knot more speed. Machinery volume, water resistance, and even air resistance could make small speed gains expensive in very large hulls.
Notable Point · 7:39-11:22
Kongo's 14-inch battlecruiser logic
Kongo joined 14-inch guns to about 27.5 knots, while Britain's continued use of 13.5-inch weapons was tied to logistics.