Featured Article Summary #179

The Lyon class was a group of battleships planned for the French Navy in 1913, with work scheduled to start in 1915. It was meant to include four ships: Lyon, Lille, Duquesne, and Tourville. Lyon and Lille were named after French cities, while Duquesne and Tourville honored French naval admirals. The design was an upgrade over the earlier Normandie class, adding an extra quadruple-gun turret to carry sixteen 34 cm guns. However, construction was stopped when World War I began in August 1914, and none of the ships were ever laid down. In 1910, France began building dreadnought battleships, and a 1912 law set a goal of 28 battleships by 1920, leading to multiple classes after the Courbet ships, including plans for the Lyon class with construction starting in 1915. Work on the Lyon design focused on its main guns, with designers debating whether to match Britain’s 38 cm armament or stick with France’s 34 cm guns; they rejected 38 cm options as too slow to develop and chose between 34 cm designs, settling on a 27500 MT design with 14 guns or, later, a slightly larger one with 16 guns. The final gun decision in early 1914 was to modify the existing 45-caliber 34 cm gun for a heavier, underwater-optimized shell, but World War I disrupted shipbuilding, causing only ships that could be completed quickly to proceed and effectively ending the Lyon class plans. The Lyon-class battleships were planned to be about 190 m long between perpendiculars (194.5 m overall), with a beam of 29 m and a draft around 8.65–9.2 m, and an estimated displacement of 29,600 tons. Their propulsion design was still undecided when the project was cancelled, but the final plan called for 40,000 CV to reach up to 21 knots. They would have used sixteen 34 cm Modèle 1912M guns in four quadruple turrets, supported by smaller secondary guns, anti-aircraft weapons, and submerged torpedo tubes. Armor protection was based on the older Normandie layout, with changes to reduce upper side protection to better defend against shells that burst underwater, including a 300 mm waterline belt and thick sloped decks and turret face armor.