Engineering:Bourayne-class cruiser

Bourayne in Algiers
Class overview
Preceded by	Sané class
Succeeded by	Hirondelle
Subclasses	Duchaffault class
Built	1867–1874
Completed	10
Lost	1
Scrapped	9
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General characteristics
Displacement	1,296.2 t (1,275.7 long tons; 1,428.8 short tons)
Length	65 m (213 ft 3 in) (loa)
Beam	10.42 m (34 ft 2 in)
Draft	4.915 m (16 ft 1.5 in) (maximum)
Installed power	2 × Scotch marine boilers 900 to 1,200 ihp (670 to 890 kW)
Propulsion	1 × compound engine 1 × screw propeller
Sail plan	Barque rig
Speed	11.3 to 12.8 knots (20.9 to 23.7 km/h; 13.0 to 14.7 mph)
Range	2,950 nmi (5,460 km; 3,390 mi) at 10 kn (19 km/h; 12 mph)
Complement	154
Armament	Bourayne class 1 × 164 mm (6.5 in) gun 3 × 140 mm (5.5 in) guns 1 × 138 mm (5.4 in) gun Duchaffault subclass 6 × 138 mm (5.4 in) guns
__1B0X_5H1P__	characteristics

The Bourayne class was a group of ten unprotected cruisers built for the French Navy in the 1860s and 1870s. The class comprised ten ships: Bourayne, Segond, Dayot, Ducouëdic, Kersaint, Vaudreuil, Hugon, Beautemps-Beaupré, Duchaffault, and Kerguélen. The last two vessels were completed to a slightly different design, and are sometimes considered to be a separate sub-class.

Design

The naval engineer Jean-Baptiste Pastoureau-Labesse prepared the design for the Bourayne class, based largely on the steam corvette Monge. His proposal was approved on 13 August 1867, but Henri Dupuy de Lôme made several alterations following Pastoureau-Labesse's departure from the navy in August 1868. The new cruiser design followed the pattern set by the larger vessels of the Sané class, which had adopted a smaller number of larger guns over the traditional numerous but light armament of earlier cruisers.

Two ships were authorized for the 1867 fiscal year, with four more added in the 1868 budget. The final tranche of four ships were authorized in 1869. During construction, two ships—Duchaffault and Kerguélen—were altered slightly, becoming a subclass. The changes were ordered by Prosper de Chasseloup-Laubat, the French naval minister, who requested a new design based around a more powerful engine from Indret. The naval engineers at the Arsenal de Cherbourg submitted a proposal for a ship based on the cruiser D'Estrées, though by that time, Charles Rigault de Genouilly had replaced Chasseloup-Laubat as naval minister. The finalized design used the same hull as the basic Bourayne design, but with some alterations to the upper works and the arrangement of the armament.

All ten vessels were initially classified as first-class avisos, but were later reclassified as third-class cruisers.

Characteristics

The first eight ships were 62.28 m (204 ft 4 in) long at the waterline and 65 m (213 ft 3 in) long overall, with a beam of 10.42 m (34 ft 2 in). They had an average draft of 4.33 m (14 ft 2 in) that was at most 4.915 m (16 ft 1.5 in) at the stern, and they displaced 1,296.2 t (1,275.7 long tons; 1,428.8 short tons). The last two ships, Duchaffault and Kerguélen, different slightly in dimensions, being 62.17 m (204 ft 0 in) long at the waterline and 65.16 m (213 ft 9 in). Their beam was identical, but draft decreased slightly to 4.257 m (13 ft 11.6 in) average and 4.8 m (15 ft 9 in) at the stern. Their displacement was slightly lower, at 1,289.3 t (1,268.9 long tons; 1,421.2 short tons). All ten ships had wooden hulls, the first eight completed with straight stems, while the Duchaffault subclass had clipper bows. All ships had a crew of 154 officers and men.

The ships' propulsion system consisted of a single horizontal compound engine that drove a single screw propeller. Steam for the engine was provided by two coal-fired Scotch marine boilers, which were vented through a funnel located amidships. The propulsion system was designed to produce 920 indicated horsepower (690 kW) for a top speed of around 12 knots (22 km/h; 14 mph). In service, these figures varied between 900 to 1,200 ihp (670 to 890 kW) and speeds of 11.3 to 12.8 knots (20.9 to 23.7 km/h; 13.0 to 14.7 mph). On her initial speed trials, Bourayne reached 12.04 knots (22.30 km/h; 13.86 mph) from 960 ihp (720 kW). Coal storage for Bourayne amounted to 186.7 t (183.8 long tons; 205.8 short tons), which allowed the ships to steam for up to 2,950 nautical miles (5,460 km; 3,390 mi) at a cruising speed of 10 knots (19 km/h; 12 mph). Duchaffault could carry up to 223.6 t (220.1 long tons; 246.5 short tons) of coal, which extended her cruising radius considerably to 3,700 nmi (6,900 km; 4,300 mi). Each vessel was fitted with a three-masted barque rig to supplement the steam engine on long voyages abroad.

Duchaffault; note the forward gun mounted on the raised forecastle and the clipper bow

The planned armament for the first eight Bourayne class was to have been a single 194 mm (7.6 in) gun and two 164 mm (6.5 in) guns, but during construction several changes were made, including a reduction of the 164 mm weapons to 140 mm (5.5 in) guns and the addition of a 138 mm (5.4 in) gun. The 194 mm gun was immediately found to be too heavy for the ships, and so while the first ships were still in the midst of their sea trials, it was replaced across all members of the class with a single 164 mm gun, with the exception of Vaudreuil, which retained her 194 mm gun until 1874. In all of the first eight ships, the main gun was placed on a rotating mount with an iron gun shield forward of the foremast. Several of the ships carried a single 84 mm (3.3 in) bronze mountain gun.

The latter pair of ships underwent similar evolutions for their armament during construction. Initially planned to carry two 194 mm guns in individual barbette mounts and a pair of 164 mm guns, one of the 194 mm pieces was ordered removed in 1869, and then in 1871, the other was replaced with a 164 mm gun while the original 164 mm guns were to be replaced with five 138 mm guns, two per broadside and one at the stern. By the time the two ships were completed in 1874, the armament had been standardized on six 138 mm M1870 guns, four of which were in rotating, shielded mounts on the broadside and the remaining pair in pivot mounts, one on the forecastle and the other on the poop deck. Both ships also carried the 84 mm mountain gun.

Modifications

The first eight ships' armament was revised several times. By 1871, the 138 mm gun was removed, leaving the 164 mm gun and the three 140 mm weapons. Between 1873 and 1877, all eight of the vessels' armament was standardized on the 164 mm gun in the forward position and five 138 mm M1870 guns. Vaudreuil received a single 100 mm (3.9 in) gun in 1875, and Ducouëdic received a pair of 37 mm (1.5 in) Hotchkiss revolver cannon in 1878. The ships lost their 164 mm gun in favor of a sixth 138 mm weapon during refits that occurred between 1880 and 1888, and most of the cruisers had been fitted with between two and eight of the 37 mm Hotchkiss revolvers. Many of the vessels carried a 65 mm (2.6 in) field gun for use by landing parties beginning in 1884.

The Duchaffault subclass underwent fewer alterations to their guns after entering service. In 1878, Kerguélen had two of the 37 mm Hotchkiss revolver cannon installed, and Duchaffault received five of the weapons in 1884. The latter vessel had a sixth Hotchkiss revolver added in 1889, by which time she had also taken on a 65 mm landing gun. During a refit in 1883, Kerguélen had her forecastle lengthened by 2.5 m (8 ft 2 in).

Ships

Hugon in 1885 en route to French Indochina

Construction data

Name	Laid down	Launched	Completed	Shipyard
Bourayne	19 November 1867	29 May 1869	July 1870	Ernest Goüin et Cie., Nantes
Segond		24 April 1869	Early 1870
Dayot		15 April 1869	April 1870
Ducouëdic	28 April 1867	30 March 1869	4 September 1870	Arsenal de Brest, Brest
Kersaint	24 January 1868	7 September 1869	17 August 1870	Arsenal de Lorient, Lorient
Vaudreuil		26 August 1870	1 March 1871
Hugon	10 November 1867	6 August 1782	1 April 1873	Arsenal de Brest, Brest
Beautemps-Beaupré	19 November 1867	4 July 1872	18 November 1874
Duchaffault	17 August 1868	17 October 1872	10 September 1874	Arsenal de Cherbourg, Cherbourg
Kerguélen	17 August 1868	19 September 1872	1 November 1874

Service history

Dayot in Algiers in the 1880s

Kersaint was struck from the naval register in December 1884, the first member of the class to leave service. A typhoon drove Dayot ashore at Tamatave, Madagascar, on 22 February 1888, destroying the ship. She was the only member of the class to be lost. Ducouëdic was struck from the naval register in January 1889 and converted into a storage hulk from 1889. Bourayne and Vaudreuil were stuck in June that year and also hulked. Segond was struck in 1894, used as a training ship from then until 1896, when she was broken up. Kerguélen was also removed from the naval register in 1894 and used in a variety of secondary roles over the following years. Hugon was struck in 1895 and sold at Lorient the following year. Beautemps-Beaupré was taken out of service in 1896 and used as a coal hulk in Corsica until 1909, when she was sold. Duchaffault met a similar end, being reduced to a coal storage hulk in Bizerte in 1897 and being sold for scrap there in 1907. Kerguélen was eventually sold at Lorient in 1913. Vaudreuil was eventually broken up in 1917. Ducouëdic was eventually sold for scrap in 1920. Bourayne followed her to the breakers' yard in 1929.

References

• Campbell, N. J. M. (1979). "France". in Gardiner, Robert. Conway's All the World's Fighting Ships 1860–1905. London: Conway Maritime Press. pp. 283–333. ISBN 978-0-85177-133-5. https://archive.org/details/conwaysallworlds0000unse_l2e2. 
• Roberts, Stephen (2021). French Warships in the Age of Steam 1859–1914. Barnsley: Seaforth. ISBN 978-1-5267-4533-0.