French Armoured Cruisers, 1887–1932

INTRODUCTION

I think this will work very well in practice. But will it work in theory?¹

The French Dupuy-de-Lôme, designed by the distinguished naval architect Louis de Bussy, was the world’s first modern armoured cruiser. Prior to the laying down of this revolutionary ship, cruisers with steel hulls had only horizontal protection in the form of a carapace over the ship’s vitals. However, the advent of shell with a high-explosive bursting charge that could wreak havoc within the upper hull and superstructures changed perceptions. Fortunately the technology to resist the new shell was at hand in the form of lightweight armour plating of homogeneous nickel steel that could be applied to the ship’s sides, and the resistance to penetration of this vertical armour would be enhanced during the 1890s by a ‘face-hardening’ process devised by the American Augustus Harvey and refined by the German armaments firm Krupp.

The Marine Nationale embraced the armoured cruiser concept with enthusiasm and remained at the forefront of development throughout the 1890s and the early 1900s. The fast cruiser was well-liked by the Jeune Ecole faction because of its commerce-raiding potential, despite its relatively high cost, while the more conservative elements of the Navy still wedded to the battleship quickly saw the value of a well-protected, powerfully-armed cruiser that could operate in the van of the battle fleet for scouting and screening. Whereas French battleship technology increasingly lagged behind that of the Royal Navy, the French armoured cruisers, which from the mid-1890s were designed by the innovative naval architect Louis-Emile Bertin and were ordered in numbers, were a major source of concern to the British. In the years 1903-04, the two years that preceded the Entente Cordiale, France completed no fewer than eleven of these ships, which were perceived as a major threat to Britain’s trade.

Louis-Emile Bertin was one of the world’s most celebrated naval architects. During the period in question he was responsible for the design of all but one of the most modern and most powerful types of French armoured cruiser. (SHD-M)

THE DESIGN PROCESS

Technical advice on the design of French battleships and cruisers was initially the responsibility of the Conseil des Travaux, set up in 1831 to examine all projects relating to the construction of warships and dockyard infrastructure. Throughout its existence the Conseil normally comprised at least eighteen members: general and senior officers of the Navy and the engineering corps, generals of artillery, and inspectors of hydraulic works.

The process with regard to new warship proposals was as follows. The council considered the staff requirements drawn up by the Conseil supérieur de la Marine (a body of senior officers that advised the Minister of Marine on overall naval policy) and made its own observations. The project was then returned to the Minister, who commissioned design studies from the Directeur du Matériel (see below). These studies, which might involve competitive submissions by naval architects belonging to the corps of constructors (Constructions Navales), were then submitted to the Conseil des Travaux for further consideration. The council would approve some studies – usually with requests for modifications – and reject others, then pass the successful submission(s) back to the Minister for approval. Constructions Navales then completed the preliminary design work and followed every step of construction, supervised by the Directeur du Matériel.

The Conseil des Travaux had a preponderance of senior admirals, who during the 1890s came to be seen as exerting a conservative influence in a period of rapid transformation. During the period in question the Conseil did little beyond raising objections to the projects placed before it. Following the appointment of Emile Bertin as Directeur du Matériel in November 1895, a Service Technique des Constructions Navales (STCN) was established, with responsibility not only for drawing up design studies on the instructions of the Minister but for providing technical advice. Initial funding for the STCN was sufficient for only four naval architects, who were therefore able to submit only preliminary studies and general plans; much of the detailed design work was left to the architects attached to the dockyards and shipyards to whom contracts were awarded, leading to a lack of standardisation in equipment and machinery.

The starboard forward 164.7mm turret of the armoured cruiser Condé. The turret is a classic example of Bertin’s tourelle-barbette, in which the lower part of the rotating gunhouse was housed within a ring of fixed armour. As can be seen from the men standing in front, the turret was relatively cramped. Note the hinged panels around the top edge of the gunhouse which provided natural ventilation when the gun was firing; the build-up of toxic gases within the turret was a major problem with QF guns. (Private collection)

In philosophical terms the Navy had made lack of standardisation a virtue. In the wake of the block obsolescence of the fleet of ironclads designed by the distinguished naval architect Dupuy de Lôme, the Budgetary Committee chaired by Etienne Lamy in 1878 declared that ‘as long as [France] builds her fleet in groups of identical ships, any progress in the naval art will weaken several elements of her naval strength at the same time’.² And throughout the 1880s all French battleships were ‘custom built’; one of the less successful outcomes of this policy was the Flotte d’échantillons of the early 1890s, comprising five battleships with similar overall capabilities but designed by different naval architects.³

The principal problem with this approach was that developments in naval artillery, projectiles and propellant, armour steel and machinery were advancing so quickly during the period 1890-1900 that ships were becoming obsolescent almost before they were completed, and the differences between individual units, rather than facilitating conceptual progress, were simply complicating maintenance and the training of personnel. Also, the French predilection for incremental technical improvements between ships of the same basic design, together with constant tinkering with plans even after ships had been laid down, resulted in increased costs and prolonged building times. During the period in question the British Royal Navy forged ahead by adopting ‘industrial’ production techniques, building large classes of ships of almost identical design with standardised weapons, protection systems and machinery. It took five years for the French to complete a battleship or cruiser and at least another year to run trials. British building times were little more than half these figures, and the trials process was simplified because the uniformity of design meant that only the first ship of a class would need to undergo exhaustive trials; lessons learned would then be applied to the remaining units of the class. Thus in the time it took the Marine Nationale to get the five battleships of the 1890 programme into service the British were able to complete eight Royal Sovereigns and nine Majestics.

An example of the problems experienced as a result of non-standardisation of equipment and machinery was recounted in the contemporary journal Le Yacht in the issue of 2 March 1904. After the armoured cruiser Léon Gambetta struck a submerged rock in fog during her trials (see Chapter 7), it was found that the star-board propeller had stripped its blades, and the propeller on the centre shaft was also damaged beyond repair. The first thought was to use the propellers manufactured for Léon Gambetta’s sisters Jules Ferry and Victor Hugo, whose construction was less advanced. However, the propellers were found to be incompatible with the shafts, and an order for new propellers had to be placed with the builder of the machinery, Penhoët of Saint-Nazaire, resulting in a delay of four/five months before trials could be resumed. The author of the report made a plea for all ships of a series to have the same specifications, so that spares were interchangeable.

ARMAMENT

French guns were as good – if not better – than any in the world. Construction techniques were advanced, as were breech mechanisms, and the Navy was well to the fore in the development of steel shell and smokeless propellant.⁴ The one area where the French Navy initially lagged behind was in the development of the medium-calibre quick-firing (QF) gun. Quick-firing guns had their propellant charge in a single brass case and a modified breech. The Royal Navy had developed a 6in (152mm) QF gun capable of up to six rounds per minute in the late 1880s, and these guns constituted the secondary battery of the battleships of the Royal Sovereign and Majestic classes and the main battery of the British 1st class cruisers.⁵ However, the French were slow to apply this principle to their 14cm and 16cm guns, and the latter calibre was in any case on the large size for a genuine QF gun. It was only during the mid-1890s that 16cm QF guns began to enter service with the Marine Nationale.

Moreover, the development of effective mediumcalibre QF guns was not without its problems. The 138.6mm Mle 1891 and Mle 1893 guns that armed Pothuau, D’Entrecasteaux and Jeanne d’Arc employed a single propellant charge in a brass case with an overall weight of 7.28kg, while the 164.7mm Mle 1893 mounted in the battleship Iéna employed a similar cartridge weighing 13.10kg. However, later models of 164.7mm gun such as the Mle 1893-1896 featured a longer firing chamber better suited to the new slow-burning powders, and the heavier 18.3kg charge was divided into two for ease of stowage and handling: in addition to the main charge, which was in the standard brass cartridge case (douille), there was a smaller, lighter fore charge in a bag of serge or silk cloth (gargousse). There were a number of accidents involving these guns prior to the Great War, and these appear to have resulted from the ignition of the fore charge by burning powder residues remaining in the breech from the previous round. Larger, slower-firing guns generally had their breeches swabbed with water between rounds, but this was not possible with a QF gun, and these accidents generally occurred during gunnery exercises,⁶ when a large numbers of rounds were fired over a short period and the barrel of the gun was already hot.

The second issue was the build-up of toxic gases from the combustion of the powder charge when the ship engaged in rapid fire. This was less of a problem when the QF guns were mounted in a battery, but in a small enclosed turret it could result in asphyxiation of the gun crew. Natural ventilation proved insufficient to resolve this problem.

PROTECTION SCHEMES

Dupuy-de-Lôme had a 100mm homogeneous steel belt that covered the entire upper part of the hull, together with a vaulted armoured deck over the machinery and magazines. The 2nd class cruisers of the Amiral Charner class that followed had a similar protection scheme, although the thickness of the side belt was slightly reduced and the top edge of the belt was one deck lower. The latter ships were designed by Jules Thibaudier, who was also responsible for the 1st class armoured cruiser Pothuau. Pothuau returned to the dimensions of Dupuy-de-Lôme, but the side belt was thinned in favour of a thicker armoured deck, which was no longer vaulted: instead there was a flat section on the ship’s axis just above the waterline, with inclined sides that joined the lower edge of the belt. This was taken a stage further in D’Entrecasteaux, designed by Engineer Lagane of the La Seyne shipyard, which although initially classified as a croiseur cuirassé (armoured cruiser) was strictly a protected cruiser with light (internal) vertical protection.

The step change in French armoured cruiser protection schemes came with the appointment of Louis-Emile Bertin as Directeur du Matériel. Bertin favoured a high belt with a tightly-compartmented cellular layer behind it, sandwiched between two protected decks to create an armoured caisson above the ship’s vitals. Directly behind the belt there was a cofferdam filled with water-excluding material, then a passageway approximately 1m wide subdivided at fixed intervals by transverse watertight bulkheads. Inboard of the passageway there were coal bunkers that provided additional protection against shell splinters. The early Bertin cruisers had a ‘thick belt’ (cuirasse épaisse) comprising a single strake of 150mm nickel steel, with a ‘thin belt’ (cuirasse mince) of 40-85mm special steel above;⁷ the plates of the thick belt were secured to a teak backing, those of the upper belt directly to the shell. In the later Bertin cruisers the light upper belt was replaced by a second strake of 130mm nickel steel, again with a teak backing.

PROPULSION MACHINERY

One of the technical areas in which the French were considered to be preeminent was propulsion machinery, and in particular marine boilers. ‘Locomotive’-type boilers, in which water in a large cylindrical drum was heated by hot gases from a coal-fired furnace located at one end of the cylinder passed through tubes, were still standard for major naval vessels in the early 1890s. However, from the end of the previous decade boilers of the Belleville or Niclausse type, in which large-diameter tubes filled with water were directly heated by the hot gases from a furnace below, were already being adopted for the latest battleships and cruisers of the Marine Nationale. Boilers of the Belleville type would subsequently be adopted by the Royal Navy, but serious technical problems were experienced for which differences in construction and deficiencies in the training of stokers were subsequently blamed.

By the late 1890s the French were opting for ‘destroyer-type’ small-tube boilers even for their armoured cruisers, largely at the prompting of Bertin, who considered that the adoption of small-tube boilers would result in improved power-to-weight ratios and greater flexibility of operation. The early small-tube boilers developed by Engineer Guyot at the Navy’s Indret propulsion establishment were bulky and proved difficult to maintain, but Bertin’s enthusiasm for this new technology was undiminished, and he was confident that the problems experienced with the early models could be resolved with the right level of determination and investment.⁸

Jules Ferry was one of three French armoured cruisers – four if the reconstructed Dupuy-de-Lôme is included – equipped with Guyot–du Temple small-tube boilers. The boilers gave serious problems during trials, and the ship’s entry into service was delayed by approximately two years before these issues were resolved. (Private collection)

The British were so convinced of the significance of these developments that Bertin was persuaded to work up his lecture notes into an English-language book with the title Marine Boilers, edited by Leslie S Robinson with a Preface by the RN’s Director of Naval Construction, Sir William White.⁹ The following extracts from White’s Preface to the 1898 edition demonstrate the high regard in which Bertin’s ideas were held:

M Bertin is the responsible designer of the latest and swiftest cruisers now building in France….

In the use of [tubulous] boilers for marine purposes the French engineers have shown remarkable courage and enterprise… [author’s italics].

English [sic] naval architects and marine engineers are happy to acknowledge the lead which their French colleagues have taken in this matter, and the benefit which they have obtained from French experiment and experience with tubulous boilers.¹⁰

However, although the French were in the forefront of boiler development they were slow to see the potential of marine turbines, and it would be the latter, allied to the all-big-gun concept, which would ultimately be responsible for the demise of the armoured cruiser as a type.

CONCLUSION

Although the armoured cruiser was obsolescent by 1914, having been overtaken in hitting power and speed by the all-big-gun, turbine-powered dread-nought ‘battle cruiser’, the French had invested a huge amount of money and effort into their own force of armoured cruisers, twenty-three of which remained in service at the outbreak of war. The seven powerful units that had entered service from 1905, the latest of which had been in service for little more than three years, constituted a key tactical element in the Armée Navale in the Mediterranean, while the cruisers of the Gloire and Gueydon classes were the workhorses of the French squadrons in the Channel and the Atlantic.

¹Translation into English of the ‘punch line’ of a contemporary joke satirising the French mentality. The French ‘Cartesian’ approach to scientific and engineering problems is often contrasted unfavourably with the British ‘pragmatic’, experience-based approach.

²Quoted in Ropp, The Development of a Modern Navy: French Naval Policy 1871–1904 , p 290.

³See Jordan and Caresse, French Battleships of World War One , Chapter 1.

⁴For a full account of development, see Jordan and Caresse, French Battleships of World War One , Introduction.

⁵The larger cruisers had two slow-firing 9.2in guns for support.

⁶Notably Jules Michelet in 1912, when she was serving with the Gunnery School (see Chapter 8).

⁷The ‘station cruisers’ of the Dupleix class, which had a sheathed hull, had a slightly different scheme (see Chapter 4).

⁸Bertin was eventually to be proved right, although it was the 1920s before the Guyot–du Temple boiler became the standard model in French cruisers.

⁹DNC and Assistant Controller of the Navy 1885–1901.

¹⁰ Marine Boilers , based on the work of L E Bertin, translated and edited by Leslie S Robertson (New York: Van Nostrand, 1906), pp ix–xi.

CHAPTER 1

FIRST STEPS: DUPUY-DE-LÔME AND THE AMIRAL CHARNER CLASS

IN THE SUMMER OF 1886 the French Ministry of Marine,¹ headed by Admiral Théophile Aube, had become concerned about the possible effect of shells containing the newly-developed high-explosive mélinite (picric acid) bursting charges on the current generation of ‘protected’ cruisers favoured by the Jeune Ecole for commerce raiding. The Conseil des Travaux² was asked for its views on the best means of protection against the new shell, and the unanimous view was that the only effective solution was side armour of the latest homogeneous steel over the entire length of the ship, extending from the upper deck to below the waterline. The Minister ordered that tests be carried out to assess the effect of the new projectiles on the old ironclad corvette Belliqueuse, and these took place early in 1887. The extent of the destruction wrought on the interior of the old ship by 14cm and 16cm cast iron shells with relatively modest melinite bursting charges was enough to convince both the Minister and the Conseil that there was an urgent need for larger, more powerful cruisers with armoured sides.

Dupuy-de-Lôme on trials in early 1895. Acclaimed by some, derided by others, Dupuy-de-Lôme was the first modern armoured cruiser designed and built for the French Marine Nationale and spawned a host of imitations abroad. (DR)

Dupuy-de-Lôme: Profile

Note: Adapted from plans dated Brest August 1893.

© John Jordan 2017

Accordingly, at its session of 20 July 1887, the Conseil set about defining suitable characteristics for both 1st class and 2nd class armoured cruisers. Its recommendations for a 1st class cruiser evolved into the Dupuy-de-Lôme; the 2nd class cruiser proposal would become the Amiral Charner (see below). The new cruiser programme would provide a political counter-balance to the resumption of work on the battleship Brennus (also agreed at the 20 July session), thereby appeasing the adherents of the Jeune Ecole, who continued to wield considerable influence both within and outside the Marine Nationale.

DUPUY-DE-LÔME

Selected naval architects were invited to submit design studies. The first to respond was Louis de Bussy, a well-respected architect who had been responsible for the design of France’s first steel-framed battleship Redoutable (launched 1876). De Bussy had been appointed Directeur des Contructions Navales in 1880 and Inspecteur Général des Contructions Navales in 1885, and was an ex officio member of the Conseil des Travaux. His preliminary design study for the new 1st class cruiser was considered by the Conseil on 18 October; general characteristics were as follows:

–Displacement: 6000 tonnes.

–Dimensions: length pp 114m; beam 15.7m; draught 7.87m max.

–Armament: 2 x 19cm guns in wing barbette mountings; 6 x 16cm guns, also in barbette mountings, grouped in a triangular arrangement fore and aft; the two centreline guns to have a command of 7.5m, the wing-mounted guns 5.5m.

–Protection: 100mm belt extending from beneath the waterline to the upper deck; a 20mm vaulted protective deck joining the main belt at its lower edge, with an 8mm splinter deck over the machinery.

–Propulsion: triple-expansion engines on three shafts rated at 14,000CV for a maximum speed of 20 knots.

The characteristics of the ship were agreed, and Brest Naval Dockyard was instructed to lay down the ship, which was authorised as part of the 1887 Programme.

NOMENCLATURE

Arguably the most distinguished naval architect of his age, Stanislas-Charles-Henri-Laurent Dupuy de Lôme (1816–65) was primarily responsible for the powerful fleet of steam-powered ironclads built for the Marine Nationale during the 1850s and 1860s, of which the most famous was the first sea-going ironclad Gloire (launched 1859); he also designed the first operational submarine, Gymnote. In 1860 he was nominated Councillor of State and represented the French Admiralty in Parliament. The following year he was appointed Inspecteur Général du Matériel de la Marine. At the beginning of the Franco-Prussian War, Dupuy de Lôme was appointed to the Committee for Defence. From 1869 to 1875 he was a député in the French parliament, and in 1877 was elected a Life Senator.

Notes:

1Armée pour essais (manned for trials)

2Armement définitif

The characteristic silhouette of Dupuy-de-Lôme, with her pronounced ‘plough’ bow incorporating a ram of forged steel. The photo was taken on 1 August 1905, shortly after her return from Kiel. Note the hinged funnel caps, which on the first funnel are in the lowered position. (Musée de la Marine)

HULL AND SUPERSTRUCTURES

The hull-form adopted by de Bussy was the one currently in vogue, with the distinctive tumblehome sides (which favoured side-mounted guns on sponsons) and a pronounced ‘plough bow’ incorporating a ram of forged steel.

The hull was built of 50kg steel on the transverse principle, with a frame separation of 1.2m throughout. There was a double bottom from the bow to frame 76, but this was completely flat, and was not extended upwards at the sides as in the later armoured cruisers designed by Bertin; it constituted the hold and was used as the floor for the main magazines and shell rooms and for the machinery. Twelve watertight transverse bulkheads divided the hull below water into thirteen watertight compartments; they extended from the ship’s bottom to the main deck.

The main deck was also the armoured deck (pont cuirassé). There were platform decks (plateformes) between the main deck and the hold for the steering gear and fresh water tanks (aft), the dynamos (forward) and coal bunkers (amidships, above the boiler rooms). Above the main deck were the ‘battery’ deck (pont de la batterie), on which the four above-water torpedo tubes were mounted, the upper deck (pont des gaillards), on which all but one of the main guns were mounted, and the shelter deck (spardeck), which not only carried the boats but was extended forward as a narrow forecastle into which the forward 16cm turret was set.

The ship was conned from a two-deck structure forward, with the compass platform and chart house on the upper level and a small, compact conning tower beneath which was linked to the Poste Central beneath the armoured deck by a cylindrical communications tube. There were two heavy ‘military’ masts that carried the platforms for the 47mm and 37mm antitorpedo boat (ATB) guns and the main searchlight projectors. Each of the masts, which were seated on the main deck, comprised a cylindrical core 0.5m in diameter housing the ammunition hoists for the ATB guns, and an outer cylinder 1.72m in diameter with the spiral ladders that gave access to the platforms for the gun crews. The ATB gun platforms were 15m above the waterline, the tops 19.8m.

The anchor-handling arrangements adopted for Dupuy-de-Lôme were unusual. Because of the tumblehome sides and the proximity of the forward 16cm turret to the bow, the main anchors were stowed flat on the deck between the turret and the bridge, and were hoisted and lowered by hinged gantry-type cranes mounted on the sides of the narrow forecastle. The capstan and the cable lockers were between the bridge and the first funnel. This clumsy arrangement would be much criticised by successive commanding officers in their evaluations of the ship.

ARMAMENT

Main guns

Shortly after construction began there were proposals to revise the layout and protection of the main armament, and the Farcot Company submitted designs for fully-enclosed turrets in place of the original barbette mountings. In the design approved by the Conseil des Travaux on 6 April 1889, the gun turntable rested on a pivot shaft that extended down to the protective deck. The gun mountings and control levers were inside the gunhouse, and the ammunition hoists were within the shaft and turned with the gunhouse; the training mechanism, which was based on hydraulic rams, was at the base of the pivot shaft (see 16cm Turret drawing).

Dupuy-de-Lôme: 16cm Pivot-type Turret

© John Jordan 2017

After further deliberation, Brest produced a revised design in which the 19cm and 16cm guns were all in single enclosed turrets, and the pivots of the 16cm turrets penetrated the armoured deck. The forward 16cm turret remained in its raised position – the gunhouse was countersunk into the raised forecastle. However, the three after 16cm turrets were now all at the same level – presumably to compensate for the additional topweight incurred by the adoption of turrets. This arrangement was approved by the Conseil on 15 October 1888. Unusually, the armoured barbette screens of the original design were retained; the broadly cylindrical gunhouses, which turned within them, were armoured only above the level of the barbettes (see Protection). The pivots housing the ammunition hoists, which were behind the armoured belt covering the upper part of the hull, were completely unprotected.

One curious anomaly of the new pivot-type turrets was that whereas the ammunition hoists for the 16cm guns rose directly from the shell rooms and powder magazines located in the hold (forward group) and on the platform deck (after group), the midship 19cm guns were separated longitudinally from their magazines, which were located two sections farther aft at hold level, abeam the forward engine room. The hoists for these magazines exited onto the pont des gaillards, at the same level as the turrets, and the projectiles and powder charges were then transported horizontally to the guns, presumably using overhead rails. This was a particularly unsatisfactory arrangement; it would not be repeated on later ships, in which the ammunition handing rooms were always directly beneath their respective guns

Both the 19cm and the 16cm guns belonged to the Modèle 1887 series, which was designed to exploit the new slow-burning powder known as poudre B, sometimes referred to as poudre Boulanger marine (named after the Minister of War of the day, General Georges-Ernest Boulanger). All the guns in this series except the large-calibre 34cm gun (42-cal) were 45 calibres long. Both the 19cm and the 16cm guns comprised a thick ‘A’ tube, reinforced over slightly more than half its length by a jacket and five hoops; a trunnion hoop was screwed on to the jacket. These and later French medium-calibre guns had an interrupted-screw breech with four threaded and four plain sectors.

A fine view of Dupuy-de-Lôme docked at Brest, showing the layout of the decks and the novel disposition of the main guns, all of which were in enclosed turrets. The three forward turrets for 16cm guns are nearest the camera, with the starboard-side wing turret for one of the two 19cm guns amidships. The foremost turret is countersunk into the forecastle so that only the upper part of armoured barbette protrudes. (DR)

The 19cm gun fired a 75kg cast iron (CI) shell with a 5kg black powder bursting charge; there was also a 90kg steel shell with a 4.3kg burster of mélinite, and this would soon be complemented by an armourpiercing shell (obus de rupture) with thicker walls and a smaller 1.6kg burster of mélinite. The 18.8kg propellant charge comprised two bags of BM9 powder. Muzzle velocity was 800m/sec with the CI shell, 770m/sec with the steel shell, and the theoretical firing cycle approximately one round per minute.

The 16cm gun fired a 45kg CI shell with a 2.1kg black powder burster; there was also a 53kg steel shell with a 3.1kg burster of mélinite, and later an armour piercing shell with a 1.0kg mélinite burster. The 13.1kg propellant charge comprised a single cartridge with BM9 powder. Muzzle velocity was as for the 19cm gun. Although the 16cm Mle 1887 used cartridge ammunition it was not a QF gun; the CI projectile had a weight comparable to that of the British 6in QF Mk I, but the steel shells were too heavy for one man to handle comfortably and the three-motion breech was slow to operate. In practice the rate of fire was probably little better than two rounds per minute. For Dupuy-de-Lôme’s immediate successors the lighter 14cm Mle 1891 gun would be preferred.

Light QF guns

For rapid fire against enemy surface ships Dupuy-de-Lôme was fitted with four of the newly-developed 65mm 50-calibre QF guns. Designed by Schneider, these hand-worked guns were on lightweight pivot mountings. Two were in tubs amidships immediately above the turrets for the 19cm guns, and two at the after end of the shelter deck, superfiring above the after wing 16cm mountings. The 65mm Mle 1891 gun was also fitted in the early battleships of the 1890 Programme (‘Flotte d’ėchantillons’) – in the two later units of the series, Masséna and Bouvet, it was replaced by the heavier 100mm QF gun.

The 65mm Mle 1891 fired a 4kg cast iron projectile with a 0.2kg black powder burster or a 4.2kg steel projectile with a 0.1kg burster of mélinite. The 0.87kg BM3 propellant was in a single cartridge case. A sliding wedge breech ensured a fast firing cycle, up to 10 rounds per minute. The Mle 1891 gun was a handy, effective weapon against the upperworks of cruisers and as a counter to enemy torpedo boats, but its projectiles were incapable of penetrating even thin armour plating.

ATB guns

The weapon of choice against enemy torpedo craft was the 47mm/40 Mle 1885, which was designed by Hotchkiss and had been sold to (or manufactured under licence by) most of the major European navies.³ When Dupuy-de-Lôme was first completed she was fitted with eight of these guns, which were mounted on the lower platforms of the two military masts. The 47mm guns were complemented by a similar number of 37mm revolver cannon, the primary role of which was to mow down the crews of attacking torpedo craft; two were mounted on each of the military masts, with a further four atop the forward superstructure. Both the 47mm and the 37mm guns had a particularly low angle of depression (in excess of -20°) to enable them to engage at close range. The composition of the ATB armament would later be modified.

Searchlight projectors

Given the comparatively short ranges of contemporary torpedoes, it was anticipated that attacks by small torpedo-carrying craft would take place under cover of darkness, either at sea or in an anchorage. Targets for the ATB guns were to be illuminated by searchlights powered by electricity. Six projectors with 60cm mirrors were fitted in Dupuy-de-Lôme: one on the upper platform of each of the two military masts (ligne haute), which could also be used for navigation in conditions of poor visibility, and four on the pont des gaillards (ligne basse). Of the latter two were at the extreme ends of the ship, and two were in the waist amidships on projecting platforms. The exposure of these lower searchlights to the elements tested the early electrics to their limits, and later ships had their searchlights arranged to give a higher level of protection when not in use.

Torpedoes

On 19 June 1890 it was decided to replace the planned fixed above-water torpedo tubes, which were slung on beams from the upper deck, by tubes on pivot mountings that could accommodate the new 45cm Mle 1892 torpedo. The tubes could be trained fore and aft of the beam using a semicircular rail set in the deck. Four were located behind watertight doors amidships on the battery deck (pont de la batterie).

The Mle 1892 torpedo was a Whitehead model initially purchased from that company’s works at Fiume and subsequently manufactured under licence at