Naval Historywith Dr. Alex

Q&A · 25:38-29:14

The machinery cost of a 28-knot Nagato

Reaching 28 knots after bulging would demand enough machinery that sacrificing a turret may be necessary, making a new ship cheaper.

BattleshipsImperial Japanese NavyNagato Class BattleshipsNaval PropulsionWarship ModernisationWashington Naval Treaty
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Question

Could a Nagato-class battleship be modernized to reach 28 knots?

Short answer

Technically yes, but the added boilers and space demands could require removing a turret, making the conversion economically doubtful.

Notes

Bulging improves protection but increases resistance, reducing speed to roughly 25 knots even after machinery renewal. The example replaces 21 boilers with ten newer ones and raises output from about 80,000 to 82,500 shaft horsepower, yet still loses speed. Reaching 28 knots would require space for perhaps five or six more boilers and probably a second funnel. Removing X turret could free the necessary space and weight, producing a six-gun fast battleship. Replacing the surviving twin mountings with triple 16-inch turrets is raised as a way to restore a nine-gun battery, though that much reconstruction could cost more than a new ship. Treaty limits provide the main reason to consider such an extensive rebuild.