Dunkerque Class Battleship - Background

Background

In 1922, the Washington Naval Treaty imposed a ten-year moratorium on the construction of new battleships. But France and Italy were allowed to replace two old battleships after 1927, for a total of 70,000 tons.

In the late 1920s, the most powerful battleships had been designed before the Washington Treaty, and were armed with four double turrets of 15-inch (381 mm) or 16-inch (406 mm) diameter guns. The Nelson class battleships, built between 1922 and 1927 with three triple 16-inch turrets forward, were based on the 1921 G3 battlecruiser concept. The top speed was, for most battleships of the time, 21–24 knots (39–44 km/h), although the Nagato class battleships had 26.5 knots (49.1 km/h; 30.5 mph) top speeds, and a few under Western flags, the fast battleships or battlecruisers, had top speeds exceeding 30 knots (56 km/h; 35 mph).

But neither France nor Italy intended to build battleships that were similar to the most recent American, British, or Japanese battleships, which were very heavily armed and armored. They wished only to modernize their aging battleships, refurbishing the propulsion machinery, and upgrading the main artillery, despite the Treaty of Washington authorizing them to undertake much more radical modernizations than could the other treaty powers. In the same way, both France and Italy reserved the right to employ their replacement capital ship tonnage allocation (70,000-long-ton (71,123 t)) as they saw fit, subject to Treaty limits – not only were two battleships of 35,000-long-ton (35,562 t) possible, but also three of 23,000-long-ton (23,369 t) or four of 17,500-long-ton (17,781 t).