page_title: French ironclad Formidable
section_title: Design
hierarchical_section_title: French ironclad Formidable / Design
caption_attribution_description: Right elevation, deck plan and hull section diagrams depicting French Amiral Baudin class battleship.
context_page_description: Formidable was an ironclad barbette ship built for the French Navy between her keel laying in late 1879 and her completion in early 1889. She was the second and final member of the Amiral Baudin class. The ships of the class was designed in response to Italian naval expansion, and carried a main battery of three 370 mm guns all mounted in open barbettes on the centerline. The armament was chosen after public pressure to compete with the very large guns mounted on the latest Italian ironclads.
  Formidable spent most of her career in the Mediterranean Fleet, where she conducted fleet training exercises each year. In 1891, she was involved in tests with tethered observation balloons. Her career passed fairly uneventfully, though she caused a grounding accident that involved two other vessels in 1895. She was modernized between 1897 and 1898, which included removing her center main battery gun and barbette and installing a battery of light quick-firing guns in its place. After returning to service, she was transferred to the Northern Squadron, based in the English Channel, where the routine of peacetime training maneuvers continued.
context_section_description: Amiral Baudin and Formidable were designed in the late 1870s as part of a naval construction program that began under the post-Franco-Prussian War fleet plan of 1872. By 1877, the Italian fleet under Benedetto Brin had begun building powerful new ironclads of the Caio Duilio and Italia classes, which demanded a French response, beginning with the ironclad Amiral Duperré of 1877. The Italian vessels carried significantly larger guns than Amiral Duperré, which prompted calls from the Chamber of Deputies to increase the caliber of future ship armament. This resulted in the development of the 370 mm (14.6 in) gun used in the Amiral Baudin class, which was in most other respects, similar to Amiral Duperré.
  Formidable was 101.4 m (332 ft 8 in) long at the waterline, with a beam of 21.34 m (70 ft) and a draft of 8.46 m (27 ft 9 in). She displaced 11,720 long tons (11,910 t). She was fitted with a pair of pole masts equipped with spotting tops for her main battery guns. The crew consisted of 625 officers and enlisted men. Her propulsion machinery consisted of two compound steam engines with steam provided by twelve coal-burning fire-tube boilers. Her engines were rated to produce 9,700 indicated horsepower (7,200 kW) for a top speed of 16 knots (30 km/h; 18 mph).
  Her main armament consisted of three 370 mm (14.6 in), 28-caliber guns mounted in individual barbette mounts, one forward, one amidships, and one aft, all on the centerline. These guns were supported by a secondary battery of four 163 mm (6.4 in) and eight or ten 138 mm (5.4 in) guns, all carried in individual pivot mounts. For defense against torpedo boats, she carried one 47 mm (1.9 in) 3-pounder gun, twelve 47 mm 3-pounder Hotchkiss revolver cannon, and eighteen 37 mm (1.5 in) 1-pounder Hotchkiss revolvers, all in individual mounts. Her armament was rounded out with six 381 mm (15 in) torpedo tubes in above-water mounts.
  The ship was protected with a combination of mild steel and compound armor; her belt was 356 to 559 mm (14 to 22 in) thick and extended for the entire length of the hull. The barbettes for the main battery were 406 mm (16 in) thick and the supporting tubes were also 406 mm. Her conning tower was 79 to 119 mm (3.1 to 4.7 in) thick.
caption: Right elevation, deck plan, and hull section of the Amiral Baudin class
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