Ruelle Foundry
| Company type | State-owned (historically) |
|---|---|
| Industry | Defense, metallurgy, artillery manufacturing |
| Founded | 1753 |
| Headquarters | Ruelle-sur-Touvre , France |
Area served | France (historically), French Armed Forces |
| Products | Cannons, guided missiles, artillery ammunition |
Number of employees | 400 (1870) |
| Parent | Naval Group (current) |
The Ruelle Foundry, also known as the fonderie de Ruelle, was established in 1753 as a cannon manufacturing facility. It has historically been instrumental in equipping the French Armed Forces with artillery. As the use of cannons waned, the foundry shifted its focus to the production of guided missiles and currently operates under the umbrella of Naval Group.
The Touvre
The location for the foundry at Ruelle-sur-Touvre was chosen because of the Touvre River, an 11.7 km tributary of the Charente, which converges near Angoulême. This river provided vital hydropower and served as a transportation route for weaponry.
Originating from four springs called the Sources de la Touvre, the Touvre emerges from Karst aquifers close to La Rochefoucauld. The adjacent rivers Tardoire and Bandiat vanish into the Karst system before resurfacing to form the Touvre.
Although brief in length, the Touvre maintains a substantial water flow, surpassing the Charente’s discharge during summer months. This ensures a dependable hydropower range between 127 and 415 hp seasonally—enough to operate all machinery for 400 workers in 1870. The aquifers feeding it prevent freezing, guaranteeing uninterrupted energy throughout the year.
At L'Houmeau, where it joins the Charente, the river becomes navigable. Prior to railway development, this inland port was crucial for shipping heavy naval artillery, as overland transport of cast iron guns was prohibitively expensive.
Charcoal and iron
The foundry at Ruelle benefited from proximity to mineral deposits, with most iron ore coming from Périgord. The extensive surrounding forests provided charcoal, a key resource for its metallurgical operations.
Up to the 1840s
Before becoming a foundry, the site functioned as a paper mill until the mid-18th century. In 1723, Claude-André de la Tache took ownership, and by 1750, Marc René, marquis de Montalembert along with his brother had purchased it, agreeing to pay an annual perpetual rent of 365 livres. The marquis transformed it into a facility focused on casting large cannons. By 1752, he obtained rights to harvest 4,800 arpents of forest over nine years to supply charcoal.
In 1755, the French government confiscated the foundry. After a legal battle lasting sixteen years, ownership was restored to the marquis in 1772; however, he was required to lease it back to the state at 20,000 livres per year plus compensation for expropriation. In 1774, the Marquis d'Artois (later King Charles X) purchased lordship over Ruelle’s foundries for 300,000 livres; machinery was appraised at 60,000 livres.
By 1776, ownership passed from the count of Artois to the French monarch who compensated him with three Champagne forests—a profitable transaction. Thereafter, management was conducted by appointed directors or leased entrepreneurs while continuing payments on the original perpetual rent until 1790.
Throughout the Revolution and subsequent conflicts, Ruelle’s foundry grew considerably under skilled direction. It underwent extensive refurbishment including installation of two reverberatory furnaces, expanded casting halls, and advanced boring machinery. The casting technique evolved from direct blast furnace casting (première fusion) to reverbatory furnace casting (deuxième fusion).
In 1840, operations from Rochefort’s bronze gun foundry and boring workshops were transferred to Ruelle. A chemical laboratory was founded in 1846. Ongoing modernization efforts continued until 1866, positioning Ruelle alongside leading heavy industry producers internationally during that period.
Contemporary Artillery
The development of contemporary artillery took shape during the mid to late 19th century, fueled by breakthroughs in metallurgy and chemical science. These advancements facilitated the creation of breech-loading rifled cannons capable of achieving significantly greater muzzle velocity compared to conventional smoothbore muzzleloaders. Early French models were predominantly constructed from cast iron.
Rifled Guns Made of Cast Iron
In the early 1850s, Ruelle produced 112 30-pounders in 1852, followed by 85 in 1853, and by mid-1854, the output included 121 30-pounders, 12 50-pounders, along with 213 iron carriages designed for coastal artillery. A substantial portion of these were manufactured to support the Crimean War (1853–1856).
The majority were smoothbore muzzleloaders, except for the novel 50-pounder trialed in 1845—a heavy smoothbore cannon firing a 50-pound shot. Previous versions discharged lighter projectiles equivalent in size to a 60 or 80-pound ball.
Among the French Navy’s initial rifled artillery pieces were the 16 cm modèle 1855 and modèle 1858-1860 guns. Most of the modèle 1858-1860 series were conversions from existing smoothbore muzzleloaders, with only one out of seven designed as breechloaders. These rifled weapons launched ogive-shaped shells nearly twice as heavy as spherical ones, necessitating steel hoops shrunk onto the barrels for structural reinforcement.
The M 1864-1866 series introduced innovative breech-loading mechanisms featuring enhanced hooping methods, screw breech designs, and effective obturation. The projectiles fired by these guns weighed three times more than earlier spherical ammunition.
By the mid-1860s, Ruelle was manufacturing M 1864-1866 models including smaller calibers and the Canon de 24 C modèle 1864, while awaiting authorization for the Canon de 27 C modèle 1864. Period engravings illustrate various production phases such as barrel forging, trunnion ring fitting, breech block assembly, and obturator installation for the 24 cm gun.
The modèle 1870 series followed with built-up construction incorporating a short steel inner tube encased within a cast iron core. An American observer remarked that although Ruelle’s casting techniques were advanced for the time, cast iron was nearing obsolescence as an artillery material.
Steel Gun Assembly and Finalization
The aftermath of the 1870-1871 Franco-Prussian War triggered significant transformations within France’s armament sector, previously dominated by state-controlled manufacturers: Ruelle and Nevers serving naval requirements; Bourges, Puteaux, and Tarbes catering to army needs. As cast iron declined in favor of cast steel production, this arrangement became less viable.
Manufacturing large all-steel artillery necessitated massive forging operations. To stimulate private sector involvement, French authorities invested in forging technology such as large-scale steam hammers. A new specialization emerged: only Compagnie des forges et aciéries de la marine et d'Homécourt at Saint-Chamond and Schneider et Cie at Le Creusot were responsible for casting barrels exceeding 16 cm caliber. Government plants like Ruelle focused on machining and assembly while relying on private foundries for casting tasks.
Following Nevers’ closure in 1880 and transfer of its resources to Ruelle, the latter became France’s sole facility assembling and finishing large steel naval guns. This shift required constructing a modernized plant over five years outfitted with heavy-duty equipment from Varall, Elwell & Middleton and a 100-ton hydraulic crane supplied by Fives-Lille, which also provided a specialized 120-ton railway transporter.
By the late 1880s, production of steel modèle 1881 guns (23–24 cm) involved several suppliers: steel main bodies originated from Creusot, Saint-Chamond, or occasionally Firth; steel rings were sourced from Saint-Chamond, Saint Etienne, and Creusot; breech components came from Saint-Chamond, Saint-Etienne, and Saint Ouen; inner tubes were primarily produced at Saint-Chamond, Firth, and possibly Ruelle.
Ammunition
The navy depended on private manufacturers for heavy artillery ammunition. Around 1885, Ruelle began manufacturing cast-iron shells to address issues with privately produced projectiles that frequently became lodged in barrels under high-pressure firing. From that point onward, the navy restricted private contracts to producing cast-iron practice grenades only.
Cartridges
By approximately 1890, Ruelle initiated brass cartridge production for quick-firing guns, allocating 1.2 million Francs toward equipment investment. The cost of cartridge manufacturing was high, approaching 4 Francs per kilogram. Although brass was initially procured externally, by 1898 Ruelle had established its own brass production capabilities.
Interwar period
A 1922 assessment highlighted Ruelle’s ability to manufacture steel guns weighing up to 10 tons, iron guns up to 40 tons, and bronze guns up to 20 tons. During the Interwar period, the foundry at Ruelle was no longer able to produce steel components for artillery exceeding 100 mm caliber. Consequently, it partnered with private companies such as Usines de la Loire, Le Creusot, Usine Saint-Jacques at Montluçon, and Société J. F. Cail & Cie in Denain.
Ruelle specialized in the machining, assembly, and finishing of large-caliber cannons. Machining operations included internal boring and precision finishing of barrel interiors, while autofrettage—applying hydraulic pressure—was used to strengthen barrel walls. Ammunition manufacturing continued to represent a substantial portion of Ruelle’s production activities.
World War II
A significant portion of Ruelle's documentation was destroyed during the occupation, resulting in lost production records. After the Liberation of France, the French resistance utilized the Ruelle Foundry to repair and adapt captured artillery that had been sabotaged. This effort involved refurbishing ten 75 mm anti-aircraft guns converted for ground use along with various other calibers, creating an effective but improvised artillery arsenal.
New names for the Ruelle foundry
Following World War II, the Ruelle facility underwent multiple organizational transformations: it became ECAN (Etablissement de Constructions d'Armes Navales) in 1970; was renamed DCN Ruelle in 1990; shifted from DGA oversight to SCN status in 2000; and eventually was privatized in 2003.
Post World War II products
After 1945, French industry showed limited enthusiasm for missile and rocket development, leading to government-driven rearmament efforts. The navy began missile projects by modifying German designs, with ECAN at Ruelle spearheading surface-to-air missile development.
In 1949, Ruelle created the subsonic Maruca missile inspired by the German Hs 117 Schmetterling. Although it was not practical for operational deployment, it played a key role in advancing France’s missile technology. This was followed by the medium-range supersonic Masurca missile system installed on Suffren-class frigates and the cruiser Colbert; however, its considerable size confined its use to vessels exceeding 5,000 tons displacement.
By the mid-1970s, French defense strategy shifted focus toward air-launched and submarine-launched anti-ship missiles. Matra collaborated with ECAN on a submarine-launched system derived from Martel and Otomat technologies. Nevertheless, Aérospatiale’s AM-39 Exocet and its submarine-launched variant SM-39 became predominant, signaling the decline of Ruelle as a missile producer.
ECAN contributed significantly to the Exocet SM-39 project by manufacturing a missile launched from a submerged capsule that surfaces before firing; this system entered service in 1985.
Additionally, ECAN produced the Canon de 100 mm modèle 53 naval gun—originally designed by STCAN as a multipurpose weapon against surface ships, aircraft, and land targets—first tested in 1958 and widely adopted internationally. This model was later succeeded by versions 64, 68, and the model 100 TR.
Public access
While Ruelle primarily functioned as a military installation, it occasionally opened its doors to the public. Notable instances include participation in the 1867 Exposition Universelle held in Paris, Ardouin-Dumazet's Voyage en France, and the completion of a heritage survey conducted in 1990.
Manufacturing methods in the late 1860s
During the late 1860s, Ruelle’s manufacturing site processed raw inputs such as charcoal, coke, bituminous coal, casting sand, refractory bricks, limestone, iron ore, and high-carbon iron containing various impurities. The foundry maintained a stockpile of 2,000 tons of charcoal—enough to operate one full blast furnace cycle—primarily produced from oak, hornbeam, European beech, and occasionally chestnut trees aged between 15 and 25 years. The charcoal yield represented approximately 17% of the initial timber weight.
Cast iron was produced on-site using blast furnaces; however, iron was also procured from external sources including Jaumellières, La Chapelle, La Motte near Feuillade, and more recently Algeria. Despite early discussions regarding economic viability, Ruelle operated its own blast furnaces—measuring 8 meters in height and 1.92 meters in diameter—where high-speed air was channeled through tuyeres via wind tunnels to achieve the required temperatures. Each furnace was managed by a team of nine workers. Approximately 40% of iron consumption originated from internal production; another 20% derived from recycled scrap metal, with the remaining 40% acquired externally. The blast furnaces on-site were decommissioned in 1868.
The casting workshop was encircled by brick furnaces reinforced with iron bands and fueled by bituminous coal to remelt blast furnace output and other metals. Reverbatory furnaces enabled metal melting within two hours. Sand molds crafted from wooden patterns were used for casting guns in both iron and bronze. The solidification of castings took between 1.5 and 5 hours but required several additional days before demolding.
Gun boring was carried out in dedicated workshops (ateliers de forerie); two such facilities were operational at that time with a third under construction. Hydraulic power played a vital role: by 1869, Ruelle operated eleven water wheels and eight turbines, including two robust turbines rated at 36 horsepower each that powered the most advanced boring machinery.
By 1869, multiple railway lines serviced the factory complex. Completed large-caliber guns were transported by horse-drawn means over a distance of seven kilometers to Angoulême for subsequent shipment by rail or barge to Rochefort.
Heritage documentation
In the late 1980s, officials conducted an inventory of heritage artifacts at the Ruelle Foundry, which included a comprehensive collection of black-and-white photographs taken in 1989 showcasing several significant buildings.