Algésiras-class ship of the line

The Emperor's barge in front of Impérial in Brest, August 1858, by Alfred Bernier
Class overview
Name	Algésiras
Operators	French Navy
Preceded by	Hercule class Napoléon
Succeeded by	Ville de Nantes class
Built	1853–1865
In service	1856–1912
In commission	1856–1889
Completed	5
General characteristics (Algésiras as built)
Type	90-gun ship of the line
Displacement	5,121 t (5,040 long tons)
Length	71.23 m (233 ft 8 in) (waterline)
Beam	16.8 m (55 ft 1 in)
Draught	8.45 m (27 ft 9 in) (full load)
Depth of hold	8.16 m (26 ft 9 in)
Installed power	8 boilers; 2,057–2,204 ihp (1,534–1,644 kW)
Propulsion	1 screw; 2 steam engines
Sail plan	Ship rigged
Speed	12 knots (22 km/h; 14 mph)
Complement	913
Armament	Lower gundeck: 18 × 36 pdr cannon; 16 × 223.3 mm (8.8 in) Paixhans guns Upper gundeck: 34 × 30 pdr cannon Quarterdeck and forecastle: 20 × 163 mm (6.4 in) Paixhans guns; 2 × 163 mm rifled muzzle-loading guns

The Algésiras class consisted of five second-rank, 90-gun, steam-powered ships of the line built for the French Navy in the 1850s. Most of the ships participated in the Second Italian War of Independence in 1859 or the Second French intervention in Mexico in the 1860s. Beginning in the mid-1860s, they were decommissioned or converted into troopships before being scrapped beginning in the early 1870s.

The Algésiras-class ships were repeats of the pioneering ship of the line Napoléon and were also designed by naval architect Henri Dupuy de Lôme. They had a length at the waterline of 71.23 metres (233 ft 8 in), a beam of 16.8 metres (55 ft 1 in) and a depth of hold of 8.16 metres (26 ft 9 in). The ships displaced 5,121 tonnes (5,040 long tons) and had a draught of 8.45 metres (27 ft 9 in) at deep load. Their crew numbered 913 officers and ratings.^[1]

The primary difference between Napoléon and the Algésiras class was that the boilers of the latter ships were moved forward of the engines. They were powered by a pair of either horizontal-return connecting-rod or trunk steam engine that drove the single propeller shaft using steam provided by eight boilers. The engines were rated at 900 nominal horsepower and produced around 2,057–2,204 indicated horsepower (2,086–2,235 PS; 1,534–1,644 kW). During their sea trials, they reached speeds of 12.2–13 knots (22.6–24.1 km/h; 14.0–15.0 mph). The ships could carry 570 tonnes (561 long tons) of coal. They were fitted with three masts and ship rigged^[1] with a sail area of 2,010 square metres (21,600 sq ft).^[2]

The armament of the Algésiras-class ships generally consisted of eighteen 36-pounder (174.8 mm (6.9 in)) smoothbore cannon and sixteen 223.3 mm (8.8 in) Paixhans guns on the lower gundeck and thirty-four 30-pounder 164.7 mm (6.5 in) cannon on the upper gundeck. On the quarterdeck and forecastle were twenty 163 mm (6.4 in) Paixhans guns and a pair of 163 mm rifled muzzle-loading guns.^[1] Intrépide, converted into a troopship while still under construction, was armed only with four 30-pounder cannon.^[3]

• Roche, Jean-Michel (2005). Dictionnaire des bâtiments de la flotte de guerre française de Colbert à nos jours. Vol. Tome I: 1671–1870. ISBN 978-2-9525917-0-6. OCLC 165892922.
• Winfield, Rif & Roberts, Stephen S. (2015). French Warships in the Age of Sail 1786–1861: Design, Construction, Careers and Fates. Barnsley, UK: Seaforth Publishing. ISBN 978-1-84832-204-2.