Design 12L carried nine twelve-inch guns in three triple turrets and a very large battery of high-angle 4.7-inch weapons. Its roughly 27,700-ton hull and 80,000-shaft-horsepower machinery were credited with twenty-seven knots, much faster than the slow sixteen-inch and fourteen-inch studies. A somewhat longer and heavier development could probably approach twenty-eight knots without an extreme increase in power. The design therefore demonstrates that British constructors were already exploring the machinery and hull proportions needed for a fast capital ship even inside a reduced treaty proposal. Design 12L is a clue rather than proof of the missing preferred design: a more credible fallback could borrow its speed while restoring heavier guns and protection. Opening the video here shows how performance data from an apparently political study can reveal the technical options available behind it.
Notable Point · 46:00-47:25
Design 12L hints at a fast battleship fallback
The 1928 Design 12L paired nine twelve-inch guns with 80,000 shaft horsepower and twenty-seven-knot speed, showing that the reduced treaty studies could still supply the hull and machinery basis for a faster fallback.