Normandie-class battleship

The main battery of the Normandie class consisted of a dozen 45-caliber Canon de 340 mm Modèle 1912M guns mounted in three quadruple turrets. One turret was placed forward, one amidships, and one aft, all on the centerline.[10] The turrets weighed 1,500 t (1,476 long tons), and were electrically trained and hydraulically elevated. The guns were divided into pairs and moved together in twin cradles; a 40 mm (1.6 in) thick bulkhead divided the turrets in half. Each pair of guns had its own ammunition hoist and magazine. They could be fired simultaneously or independently.[12] Had the ships been completed, these would have been the first quadruple turrets in the world.[13]

The guns had a range of 16,000 meters (17,000 yd) and had a rate of fire of two rounds per minute. The shells were 540-kilogram (1,190 lb) armor-piercing rounds and were fired with a muzzle velocity of 800 meters per second (2,600 ft/s).[14] Each gun was to have been supplied with 100 rounds of ammunition.[15] Five 3.66 m (12 ft) rangefinders provided fire-control for the main battery. Two of the rangefinders were mounted on the conning tower and the other three were placed atop each of the turrets. The turrets also had auxiliary gunnery-control stations.[16]

The ships would also have been armed with a secondary battery of twenty-four 55-caliber 138.6 mm Modèle 1910 guns, each singly mounted in casemates near the main-gun turrets.[17] These guns fired a 36.5 kg (80 lb) shell at a muzzle velocity of 830 m/s (2,700 ft/s).[18] The guns would have been supplied with 275 rounds of ammunition each.[16] Six Canon de 47 mm (1.9 in) Modèle 1902 anti-aircraft guns, which were converted from low-angle guns, would also have been carried by the ships.[10][19] The ships also would have been equipped with six underwater 450 mm (17.7 in) torpedo tubes, three on each broadside.[10] Each ship was to be supplied with 36 torpedoes.[16]

Armor plate for Normandie being manufactured in Saint-Etienne, 1916

The armor belt of the Normandie-class ships was made from Krupp cemented armor and extended almost the entire length of the hull (170 meters (557 ft 9 in)), save 5 meters (16 ft 5 in) at the stern. The belt consisted of two rows of plates that were a total of 4.05 meters (13 ft 3 in) high, of which 1.7 meters (5 ft 7 in) was below the waterline. The thickest portion of the armor protected the hull between the barbettes of the end turrets and was 300 millimeters (11.8 in) thick. Each of the upper plates was tapered to a thickness of 240 millimeters (9.4 in) at its top edge and the lower plates were tapered to 100 millimeters (3.9 in) at their bottom edge. From No. 1 barbette to the bow, the plates progressively reduced in thickness from 260 to 160 millimeters (10.2 to 6.3 in) at the bow; the upper edges also progressively reduced from 190 to 140 millimeters (7.5 to 5.5 in) while the bottom edge of these plates was 80 millimeters (3.1 in) thick. Aft of the rear turret, the armor plates were progressively reduced in thickness from 260 millimeters to 140 millimeters. Their upper edges also progressively thinned from 190 to 100 millimeters (7.5 to 3.9 in) and their lower edges were the same 80 millimeters in thickness as their forward equivalents. The aft belt terminated in a 180-millimeter (7.1 in) transverse bulkhead.[20]

Above the waterline belt was an upper strake of 160-millimeter armor that extended between the fore and aft groups of casemates for the secondary armament. The portions of the barbettes that extended outside the upper armor were protected by 250-millimeter (9.8 in) plates while the interior surfaces were only 50 millimeters (2 in) thick to save weight. The turrets were protected with an armor thickness of 300 millimeters on their faces, 210 millimeters (8.3 in) on the sides, and 100 millimeters on the roof. The sides of the conning tower were 266 millimeters (10.5 in) thick and its roof was also 100 millimeters thick. The lower armored deck consisted of a single 14-millimeter (0.6 in) plate of mild steel for a width of 7 meters (23 ft) along the centerline and another layer of the same thickness was added outboard of that. The deck sloped downwards to meet the bottom of the waterline belt and a 42-millimeter (1.7 in) plate of armor steel reinforced the sloped portion of the deck to give a total thickness of 70 millimeters (2.8 in). Two layers of 13 millimeters (0.5 in) plating made up the center of the upper armored deck and it was reinforced to a total of 80 millimeters (3.1 in) along the edges and 48 millimeters (1.9 in) above the magazine.[21]

The hull of the Normandies had a double bottom 1.6 meters (5 ft 3 in) deep. Their propulsion machinery spaces and magazines were protected by a torpedo bulkhead that consisted of two 10-millimeter (0.4 in) layers of nickel-chrome steel plates. The outer side of the bulkhead was lined with a 10-millimeter plate of corrugated flexible steel intended to absorb the force of a torpedo detonation. Another measure intended to dissipate the force were 80-centimeter-diameter (31.5 in) tubes that extended from the double bottom to the upper armored deck that were intended to divert the gases of the detonation away from the torpedo bulkhead. Concerned about the possibility of capsizing after asymmetric flooding, the design incorporated empty compartments below the waterline and outboard of the fore and aft 34-centimeter magazines, the engine rooms and the midships 138.6-millimeter magazines that were intended to be flooded to correct any list.[21]

The boilers intended for Normandie and Gascogne were used to replace the worn-out boilers of various destroyers,[26] namely the Aventurier-class destroyers purchased from Argentina in 1914[27] and the three Aetos-class ships seized from the Royal Hellenic Navy in late 1916. Those boilers built for Flandre were installed in new anti-submarine ships. The armor plate and turntables of Gascogne's turrets had been ordered from Fives-Lille, whose factory was captured by the Germans in 1914. They were discovered in one of Krupp's factories in Germany in 1921 and returned to the Navy.[26]

In January 1918, a final wartime order specified that the ships remained suspended, but that all material that had been stockpiled for work would remain in place. By that time, some 3,086 t (3,037 long tons) of steel plating that had been earmarked for Gascogne had been taken for other uses.[28]

On 22 November, days after the Armistice with Germany, the design staff sent the General Staff a proposal to complete the first four Normandies to a modified design. The General Staff replied that the ships would need a top speed of 26 to 28 kn (48 to 52 km/h; 30 to 32 mph) and a more powerful main battery.[29] Since the dockyard facilities had not been enlarged during the war, the size of the ships could not be significantly increased. This allowed for only modest improvements, particularly for the installation of anti-torpedo bulges. In February 1919, the General Staff decided that the ships would be completed anyway, because new vessels incorporating the lessons of the war could not be completed for at least six to seven years, due to the lengthy design studies such battleships would require.[30]

The Technical Department created a revised design that incorporated some improvements. The machinery for the four ships that had been launched during the war would be retained;[31] increasing their speed to 24 knots (44 km/h; 28 mph) required a corresponding increase to 80,000 shp (60,000 kW), which could be obtained by building more powerful turbines.[32] The elevation of the main guns was to be increased to 23–24 degrees, which would increase the range of the guns to 25,000 m (82,000 ft) lest they be out-ranged by foreign battleships.[31] The need to engage targets at longer ranges was confirmed by the examination of one of the ex-Austrian Tegetthoff-class ships that had been surrendered to France at the end of the war. The main armored deck was to be increased to 120 mm (4.7 in) to increase resistance to plunging fire. The submerged 450 mm torpedo tubes were to be replaced with deck-mounted 550 mm (21.7 in) tubes, and fire-control equipment was to be improved. Equipment for handling a two-seat reconnaissance aircraft and a single-seat fighter was also to be installed.[33]

After the war, Vice Admiral Pierre Ronarc'h became Chief of the General Staff, and in July 1919 he argued that the Italian Navy was the country's primary naval rival, and that they might resume work on the Francesco Caracciolo-class battleships that had been suspended during the war. He suggested there were three options for the first four Normandies: complete them as designed, increase the range of their guns and improve their armor, or lengthen their hull and install new engines to increase speed. The Technical Department determined that lengthening the hulls by 15 m (49 ft) could increase speed by as much as 5 kn (9.3 km/h; 5.8 mph). Nevertheless, by 12 September 1919, Ronarc'h had decided that completing the ships would be too expensive for the fragile French economy.[34] Plans for the first four ships included converting them into cargo ships, oil tankers, or passenger liners, and using them as floating oil depots, but these ideas were ultimately rejected.[35] The ships were formally cancelled in the 1922 construction program, and were laid up in Landevennec and cannibalized for parts before being broken up in 1923–1926.[34] Much of the salvaged material was incorporated into completing Béarn and in modernizing the battleship Courbet.[36]

Plans to complete Béarn included replacement of the coal-fired boilers with eight oil-fired Niclausse boilers and new, more powerful turbines. A new quadruple turret that allowed for greater range was considered, along with twin turrets mounting 400 mm (16 in) guns.[32] The battleship was launched on 15 April 1920 to clear the slipway. A temporary 43 m × 9 m (141 ft × 30 ft) wooden platform was built atop the lower armored deck later that year to serve as a flight deck for aircraft landing trials. Transverse arresting wires that were weighted by sandbags were improvised and the evaluation successfully took place off Toulon in late 1920. In 1922, the Navy instead decided to complete the ship as an aircraft carrier. Conversion work began in August 1923, and was completed by May 1927 using the hybrid propulsion system from Normandie with a dozen Normand boilers.[37] The ship was the first carrier of the French Navy. She served in the fleet through World War II, generally being used as a ferry for aircraft; she did not see any combat as she spent most of the war in the Caribbean in the island of Martinique.[38] In 1944, she was refitted in the United States and equipped with a battery of modern American anti-aircraft guns.[23] She remained in service through the First Indochina War, still as an aircraft ferry. The ship was ultimately broken up for scrap in 1967.[39]