Alger-class cruiser

The Alger class was a class of protected cruisers of the French Navy. The class comprised Alger, Isly and Jean Bart.

Alger
Class overview
Name: Alger class
Builders: Arsenal De Rochefort Arsenal de Brest, Arsenal de Cherbourg
Operators:  French Navy
Preceded by: Troude class
Succeeded by: Friant class
Built: 1887–1893
In commission: 1891–1914
Completed: 3
Retired: 3
General characteristics
Class and type: Protected cruiser
Displacement: 4,044 to 4,406 long tons (4,109 to 4,477 t)
Length: 105 m (344 ft 6 in) pp
Beam: 12.98 m (42 ft 7 in)
Draft: 6.10 to 6.45 m (20 ft 0 in to 21 ft 2 in)
Installed power:
Propulsion:
  • 2 × triple-expansion engines
  • 2 × screw propellers
Speed: 19 to 19.5 knots (35.2 to 36.1 km/h; 21.9 to 22.4 mph)
Range: 3,200 nmi (5,900 km; 3,700 mi) at 10 knots (19 km/h; 12 mph)
Complement: 387–405
Armament:
Armor:

Design

By 1886, Admiral Théophile Aube had become the French Minister of Marine. Aube was an ardent supporter of the Jeune École doctrine, which envisioned using a combination of cruisers and torpedo boats to defend France and attack enemy merchant shipping. By the time Aube had come to office, the French Navy had laid down three large protected cruisers that were intended to serve as commerce raiders: Sfax, Tage, and Amiral Cécille. His proposed budget called for another six large cruisers and ten smaller vessels, but by the time it was approved later in 1886, it had been modified to three large cruisers, two medium cruisers, and six small cruisers. The three Algers filled the requirement for the large vessels,[1][2] and they proved to be the last of the large commerce-raiding cruisers built for the French fleet.[3]

General characteristics and machinery
Profile drawing of an early version of the Alger design, c. 1890

The ships of the Alger class were 105 m (344 ft 6 in) long between perpendiculars and 105.5 m (346 ft) long at the waterline, with a beam of 12.98 m (42 ft 7 in) and a draft of 6.10 to 6.45 m (20 ft 0 in to 21 ft 2 in). They displaced 4,313 long tons (4,382 t). Their hulls featured a pronounced ram bow and a tumblehome shape, along with a sloped, overhanging stern. The ships had a minimal superstructure, consisting primarily of a small conning tower and bridge forward. Their crew varied over the course of their careers, amounting to 387–405 officers and enlisted men.[3][4]

Reports of the ships' rigging are mixed; according to Conway's All the World's Fighting Ships, the cruisers carried a pair of heavy military masts fitted with fighting tops for some of their light guns and observation positions. But in an article in Warship International quoting the 1905 edition of the Marine Almanac, Fisher states that the vessels were originally barque rigged, the sails being removed by the mid-1890s.[3][4] An 1893 article in the Scientific American Supplement, using an illustration from the French newspaper L'Illustration, depicts Alger with military masts.[5]

The ship's propulsion system consisted of a pair of vertical triple-expansion steam engines for Alger and horizontal triple-expansion engines for Jean Bart and Isly, driving two screw propellers in all three vessels. Steam was provided by twenty-four coal-burning Belleville type water-tube boilers for Alger, while Jean Bart and Isly received eight of the older fire-tube boilers. Each ships' boilers were ducted into two funnels. Their machinery was rated to produce 8,000 indicated horsepower (6,000 kW) for a top speed of 19 to 19.5 knots (35.2 to 36.1 km/h; 21.9 to 22.4 mph). Normal coal storage amounted to 860 long tons (870 t), but up to 940 long tons (960 t) could be carried. This permitted a cruising radius of 3,200 nautical miles (5,900 km; 3,700 mi) at 10 knots (19 km/h; 12 mph) with the normal load, and 4,000 nmi (7,400 km; 4,600 mi) at the same speed with the maximum.[3][4]

Armament and armor
Isly underway, c. 1894

The ships were armed with a main battery of four 164 mm (6.5 in) 28-caliber guns and six 138 mm (5.4 in) 30-cal. guns. All of these guns were placed in individual pivot mounts on the upper deck; the 164 mm guns were in sponsons located fore and aft, with two guns per broadside. Four of the 138 mm guns were in sponsons between the 164 mm guns, one was in an embrasure in the forecastle and the last was in a swivel mount on the stern.[4] The 100 mm guns were supplied with a variety of shells, including solid cast iron projectiles and explosive armor-piercing shells, both of which weighed 30 kg (66 lb). The guns fired with a muzzle velocity of 590 m/s (1,900 ft/s).[6]

For close-range defense against torpedo boats, they carried a pair of 65 mm (2.6 in) 9-pounder guns, eight 47 mm (1.9 in) 3-pounder Hotchkiss guns, and eight 37 mm (1.5 in) Hotchkiss revolver cannon. They were also armed with five 350 mm (14 in) torpedo tubes in their hull above the waterline.[4]

Armor protection consisted of a curved armor deck that was 50 mm (2 in) thick on the flat portion, increasing in thickness to 100 mm (4 in) on the sides, where it curved down to meet the sides of the hull. Above the deck, the ships had a 0.79 m (2 ft 7 in) wide cofferdam that was extensively compartmentalized to control flooding in the event of damage above the deck. The ships had 50 to 75 mm (2 to 3 in) plating on the conning tower. Isly and Jean Bart received gun shields that were 50 mm thick.[4]

Construction
Name Laid down[4] Launched[4][7] Completed[4] Shipyard[4]
Alger November 1887 23 November 1889 1891 Arsenal de Cherbourg, Cherbourg
Isly August 1887 23 June 1891 1893 Arsenal de Brest, Brest
Jean Bart September 1887 November 1889 1891 Arsenal de Rochefort, Rochefort

Service history
Jean Bart early in her career

Notes
  1. Gardiner, pp. 308–310.
  2. Ropp, pp. 158–159, 172.
  3. Fisher, p. 238.
  4. Gardiner, p. 310.
  5. The New Cruiser Alger, p. 14669.
  6. Friedman, p. 221.
  7. Gardiner & Gray, p. 193.
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References
  • Fisher, Edward C., ed. (1969). "157/67 French Protected Cruiser Isly". Warship International. Toledo: International Naval Research Organization. VI (3): 238. ISSN 0043-0374.
  • Friedman, Norman (2011). Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of All Nations; An Illustrated Directory. Annapolis: Naval Institute Press. ISBN 978-1-84832-100-7.
  • Gardiner, Robert, ed. (1979). Conway's All the World's Fighting Ships 1860–1905. London: Conway Maritime Press. ISBN 978-0-85177-133-5.
  • Gardiner, Robert & Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships: 1906–1921. Annapolis: Naval Institute Press. ISBN 978-0-87021-907-8.
  • Ropp, Theodore (1987). Roberts, Stephen S. (ed.). The Development of a Modern Navy: French Naval Policy, 1871–1904. Annapolis: Naval Institute Press. ISBN 978-0-87021-141-6.
  • "The New Cruiser Alger". Scientific American Supplement. New York: Munn & Co. XXXVI (918). 5 August 1893.
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