Descartes-class cruiser

File:French cruiser Pascal.jpg Pascal, c. 1897–1900
Class overview
Name:	Descartes class
Builders:	Arsenal de Toulon, Arsenal De Loire
Operators:	French Navy
Preceded by:	Linois class
Succeeded by:	D'Assas class
Built:	1892–1897
In commission:	1896–1920
Completed:	2
Retired:	2
General characteristics
Type:	Protected cruiser
Displacement:	3,960 long tons (4,020 t)
Length:	96.32 m (316 ft) pp
Beam:	12.98 m (42 ft 7 in)
Draft:	6.5 m (21 ft 4 in)
Installed power:	16 × water-tube boilers 8,500 ihp (6,300 kW)
Propulsion:	2 × triple-expansion steam engines 2 × screw propellers
Speed:	19.5 knots (36.1 km/h; 22.4 mph)
Range:	5,500 nmi (10,200 km; 6,300 mi) at 10 knots (19 km/h; 12 mph)
Complement:	383–401
Armament:	4 × 164 mm (6.5 in) guns 10 × 100 mm (3.9 in) guns 8 × 47 mm (1.9 in) guns 4 × 37 mm (1.5 in) guns 2 × 450 mm (17.7 in) torpedo tubes
Armor:	Deck: 30 to 60 mm (1.2 to 2.4 in) Conning tower: 70 mm (3 in)

The Descartes class comprised two protected cruisers of the French Navy built in the early 1890s; the two ships were Descartes and Pascal. They were ordered as part of a naval construction program directed at France's rivals, Italy and Germany, particularly after Italy made progress in modernizing its own fleet. The plan was also intended to remedy a deficiency in cruisers that had been revealed during training exercises in the 1880s. As such, the Descartes-class cruisers were intended to operate as fleet scouts and in the French colonial empire. The ships were armed with a main battery of four 164 mm (6.5 in) guns supported by ten 100 mm (3.9 in) guns and they had a top speed of 19.5 knots (36.1 km/h; 22.4 mph).

Descartes and Pascal were initially sent to French Indochina in the late 1890s, where they participated in the campaign to suppress the Boxer Uprising in Qing China. Descartes was recalled to France in 1902 to serve in the Atlantic Division while Pascal remained in East Asia, serving until 1904 when she was deactivated due to poor condition. Descartes was sent back to East Asia in 1905 and later to French Madagascar before returning to France in 1907, thereafter serving with the main French fleets in the Mediterranean Sea and English Channel. Pascal was sold to ship breakers in 1911, while Descartes served another stint in the Atlantic Division. She remained there during the first three years of World War I before returning to France in 1917, where she was disarmed and decommissioned. She was struck from the naval register in 1920, but what ultimately became of the ship is unknown.

Design

File:'Italia,' first class ironclad of the Italian Navy LCCN2003672917 cropped.jpg

The fast Italian ironclad Italia, the threat of which prompted the French naval program of 1890

In the late 1880s, the Italian Regia Marina (Royal Navy) accelerated construction of ships for its fleet and reorganized the most modern ironclad battleships—the Duilio and Italia classes—into a fast squadron suitable for offensive operations. These developments provoked a strong response in the French press. The Budget Committee in the French Chamber of Deputies began to press for a "two-power standard" in 1888, which would see the French fleet enlarged to equal the combined Italian and German fleets, then France's two main rivals on the continent. This initially came to nothing, as the supporters of the Jeune École doctrine called for a fleet largely based on squadrons of torpedo boats to defend the French coasts rather than an expensive fleet of ironclads. This view had significant support in the Chamber of Deputies.

The next year, a war scare with Italy led to further outcry to strengthen the fleet. To compound matters, the visit of a German squadron of four ironclads to Italy confirmed French concerns of a combined Italo-German fleet that would dramatically outnumber their own. Training exercises held in France that year demonstrated that the slower French fleet would be unable to prevent the faster Italian squadron from bombarding the French coast at will, in part because it lacked enough cruisers (and doctrine to use them) to scout for the enemy ships.

To correct the weaknesses of the French fleet, on 22 November 1890, the Superior Council authorized a new construction program directed not at simple parity with the Italian and German fleets, but numerical superiority. In addition to twenty-four new battleships, a total of seventy cruisers were to be built for use in home waters and overseas in the French colonial empire. The Descartes class were ordered to as part of the program.

General characteristics and machinery

The two Descartes-class cruisers were 96.32 m (316 ft) long between perpendiculars, with a beam of 12.98 m (42 ft 7 in) and a draft of 6.5 m (21 ft 4 in). They displaced 3,960 long tons (4,020 t). Like most French warships of the period, the Descartes-class cruisers' hulls had a pronounced ram bow, tumblehome shape, and a short forecastle deck . Below the waterline, the hulls were covered in a layer of wood and copper sheathing to protect them from biofouling on long voyages overseas. The ships had a minimal superstructure, consisting primarily of a small conning tower and a bridge. They were fitted with pole masts with spotting tops for observation and signaling purposes. The ships suffered from stability problems and had to have ballast added after completion. Their crew varied over the course of her career, and consisted of 383–401 officers and enlisted men.

The ships' propulsion system consisted of a pair of vertical triple-expansion steam engines driving two screw propellers. Steam was provided by sixteen coal-burning Belleville-type water-tube boilers that were ducted into two funnels. Their machinery was rated to produce 8,500 indicated horsepower (6,300 kW) for a top speed of 19.5 knots (36.1 km/h; 22.4 mph). Coal storage amounted to 543 long tons (552 t), which gave the ships a cruising radius of 5,500 nautical miles (10,200 km; 6,300 mi) at 10 knots (19 km/h; 12 mph) and 1,000 nmi (1,900 km; 1,200 mi) at 19.5 knots.

Armament and armor

File:St Idelsbade (Saint-Idesbalde). Pièce de 100 de marine - Fonds Berthelé - 49Fi1270 (cropped).jpg

A 100 mm (3.9 in) Model 1891 gun in a pivot mount

The ships were armed with a main battery of four 164 mm (6.5 in) Modèle 1893 45-caliber guns. They were placed in individual sponsons clustered amidships, two guns per broadside. They were supplied with a variety of shells, including solid, 45 kg (99 lb) cast iron projectiles, and explosive armor-piercing (AP) and semi-armor-piercing (SAP) shells that weighed 54.2 kg (119 lb) and 52.6 kg (116 lb), respectively. The guns fired with a muzzle velocity of 770 to 800 m/s (2,500 to 2,600 ft/s).

The main battery was supported by a secondary battery of ten 100 mm (3.9 in) Modèle 1891 guns, which were carried in a variety of mounts. Two guns fitted with gun shields were placed side-by-side on the upper deck, four more were in the upper deck forward in casemates. Another pair of guns were in sponsons further aft, and the remaining pair were in pivot mounts on the upper deck aft. The sides of the ships were recessed to allow the primary and secondary guns to fire directly ahead or astern. The guns fired 14 kg (31 lb) cast iron and 16 kg (35 lb) AP shells with a muzzle velocity of 710 to 740 m/s (2,300 to 2,400 ft/s).

For close-range defense against torpedo boats, they carried eight 47 mm (1.9 in) 3-pounder Hotchkiss guns and four 37 mm (1.5 in) 1-pounder guns. These were all in single pivot mounts, distributed along the length of the ships. They were also armed with two 450 mm (17.7 in) torpedo tubes in her hull above the waterline. The torpedoes were the M1892 variant, which carried a 75 kg (165 lb) warhead and had a range of 800 m (2,600 ft) at a speed of 27.5 knots (50.9 km/h; 31.6 mph).

Armor protection consisted of a curved armor deck that was 30 mm (1.2 in) thick on the flat portion, curving down at the sides, where it increased in thickness to 60 mm (2.4 in). Above the deck, a cellular layer of watertight compartments was intended to contain flooding below the waterline. A light splinter deck covered the propulsion machinery spaces to protect them from shell fragments that penetrated the main armor deck. The gun shields for the deck-mounted 100 mm guns were 50 mm (2 in) thick. The ships had 70 mm (2.8 in) plating on the conning tower.

Construction

Construction data

Name	Laid down	Launched	Completed	Shipyard
Descartes	August 1892	27 September 1894	July 1896	Chantiers de la Loire, Saint-Nazaire
Pascal	December 1893	26 September 1895	1897	Arsenal de Toulon, Toulon

Service history

File:Descartes class drawing.jpg

Plan and profile drawing of the Descartes class

Descartes and Pascal were deployed to French Indochina after entering service in 1897, though Pascal did not leave France until after completing her sea trials by January 1898. Both ships were present during the Boxer Uprising in Qing China; they were among the vessels France contributed to the Eight-Nation Alliance that defeated the Boxers in the early 1900s. Descartes returned to France in 1902, when she joined the Atlantic Division, though Pascal remained in East Asia. Pascal's condition deteriorated after several years abroad, where the French lacked sufficient shipyard facilities, and by 1904, her engines could no longer reach her design speed. She saw little further use thereafter, in part because the French Navy had settled on building a fleet of armored cruisers to fulfill the roles that the Descartes class had been intended to fill. She was struck from the naval register in 1911 and later broken up.

In the meantime, Descartes was sent on a second deployment to East Asia in 1905. She had been transferred to French Madagascar by 1907, and later that year, she returned France to join the Mediterranean Squadron. Descartes was then transferred to the Northern Squadron. By 1914, the ship was operating with the Atlantic Division; she was patrolling in Central American waters and was slated to return to France when World War I started in July. She instead remained in the region and joined the French and British vessels searching for the German light cruiser SMS Karlsruhe that was attacking merchant shipping in the area, though they failed to locate her. Descartes spent the next three years patrolling the West Indies, seeing no action. After returning home in 1917, she was decommissioned and disarmed, her guns being used as field artillery and to arm patrol vessels. She was struck from the naval register in 1920, but her ultimate fate is unknown.