C-6 was a of the Spanish Navy in commissioned in 1930. She served initially under the Kingdom of Spain, then as a unit of the Spanish Republican Navy under the Second Spanish Republic. She took part in the Spanish Civil War on the side of Republican faction loyal to the government of the Second Spanish Republic. She was scuttled in 1937 during the civil war.

Design

Construction and commissioning In 1915, the Spanish Cortes Generales passed the Miranda Law, a naval construction program which called for a Spanish Navy force that included 28 submarines. Shortages during World War I (1914–1918) and budgetary limitations led to delays in the program, but a new naval law passed on 1922 authorized the construction of the six s. The Sociedad Española de Construcción Naval (SECN) built all six of the submarines at Cartagena, Spain.

C-6 was the sixth and final vessel of the class. SECN laid her keel on 1925 and launched her on 1929. She was commissioned on 1930.

Service history Kingdom of Spain, 1930–1931

Upon commissioning, C-6 was assigned to the submarine squadron at Cartagena. She participated in maneuvers in the Cantabrian Sea off the northern coast of Spain during September and October 1930.

Second Spanish Republic, 1931–1936

On 14 April 1931, the Second Spanish Republic was proclaimed, replacing the Kingdom of Spain. The Spanish Navy came under the republic's control as the Spanish Republican Navy. In January 1932, President of the Republic Niceto Alcalá Zamora came aboard C-6 while presiding over the dedication of a pier at Alicante.

All six C-class submarines took part in fleet maneuvers during May and June 1934. C-6 and her sister ship subsequently conducted a cruise in the Mediterranean Sea, during which they visited Bizerte in Tunisia; Alexandria in Egypt; Haifa in Mandatory Palestine; Rhodes in the Italian Dodecanese; Thessaloniki and Piraeus in Greece, La Maddalena on Sardinia; and Toulon in France. They concluded the cruise with their arrival at Cartagena.

The six C-class submarines departed Cartagena on 29 July 1935 to begin a lengthy training cruise. They called at Melilla on the coast of North Africa from to and at Cádiz from . They then set course for the United Kingdom, reaching Plymouth, England, in mid-August. They subsequently visited Brest in France, Ferrol, and the Canary Islands before proceeding to West Africa, where they called at Dakar in Senegal and Villa Cisneros in Río de Oro. They then returned to the Canary Islands for a stop at Las Palmas on Gran Canaria and called at Larache in Spanish Morocco before concluding the cruise with their arrival at Cartagena in September 1935.

C-6 was one of several submarines that took part in maneuvers in the Canary Islands during the first half of May 1936. She returned to Cartagena upon their completion.

Spanish Civil War On 17 July 1936, the Spanish Civil War began, with Nationalist forces under Francisco Franco opposing Republican forces which remained loyal to the Second Spanish Republic. At the time, C-6 was at Cartagena as a unit of the Cartagena division. Early on , the division received orders from the Republican government to patrol the Mediterranean along the Andalusian coast between Cabo de Gata and the Strait of Gibraltar to intercept ships carrying Nationalist troops and equipment from North Africa to Spain. C-6, C-3, and their sister ships and got underway immediately, rendezvoused at sea with the submarine , and began the patrol. They took up a patrol line along the Andalusian coast, and the other submarines of the Cartagena division joined them over the following days.

It quickly became apparent that most of the division's officers supported the Nationalists while the crews supported the Republicans, so the crews mutinied, established "ship's committees" of sailors with the power to choose their officers and direct the operations of their vessels, and placed most of the officers under arrest. Only two days into the operation, on 20 July, the submarine division entered the harbor at Málaga, where the division's commander, (Frigate Captain) Francisco Guimerá Bosch, and most of the other senior officers in the division were relieved of command and transferred to the prison ship Monte Toro. C-6′s commanding officer, Capitán de corbeta (Corvette Captain) Romero Carnero, was among those removed, and an alférez de navío (ship-of-the-line ensign) took command of the submarine. On 1936, all destroyers and submarines at Málaga deployed around Cádiz to intercept a Nationalist convoy that proved to be a decoy. Then C-6 and her sister ships , and C-3 received instructions to form a patrol arc along the coast of North Africa off the harbor at Ceuta to prevent the entrance of the Nationalist light cruiser , which had left Ferrol bound for the Strait of Gibraltar and was thought to be headed for Ceuta.

The need for experienced officers to command Republican submarines led to Romero Carnero's reinstatement as C-6′s commanding officer on 1936. That day, C-6 and C-3 got underway bound for the Cantabrian Sea along Spain's northern coast. C-3 suffered a mechanical breakdown that forced her to return to Cartagena, but C-6 continued alone and arrived at Gijón on 1936. While at Gijón, Romero received word that Almirante Cervera was anchored off the coast of Asturias and was bombarding Republican forces there. Rather than using this information to attack Almirante Cervera, Romero had C-6 get underway for San Sebastián, where the Nationalist battleship España reportedly was anchored off the coast. After Romero also failed to attack España, claiming that technical difficulties prevented it, C-6′s crew accused him of Nationalist sympathies, mutinied, and once again replaced him with the alférez de navío (ship-of-the-line ensign). The Republican government ordered C-6 to return to the Mediterreanean Sea.

On 1 September 1936, the president of C-6′s ship's committee, a torpedo boat commander, took command of C-6. C-6 departed that day for another deployment to Spain's northern coast, arriving at Gijón on 1936. On 1936, C-6, C-3 and C-4 again set out for the Mediterranean, with C-3 and C-4 reaching Málaga on and C-6 continuing on to Cartagena.

By the beginning of 1937, C-6 was based at Málaga. She was in port there when a Nationalist air raid killed her commanding officer on 1937. On she returned to Cartagena, avoiding an attack on Málaga by Nationalist warships.

The Soviet Union actively supported the Republican faction, and on 1937 a Soviet Navy officer took command of C-6. Under his command, C-6 carried out several training exercises in the following days. He then decided to attack Nationalist ships anchored at Ceuta, but bad weather forced him to cancel these plans. Days later, C-6 got underway to attack Nationalist ships at Palma de Mallorca on Mallorca in the Balearic Islands, but a Nationalist aircraft damaged her in a bombing attack on 1937, forcing her to turn back for Cartagena. She reached Cartagena on and began repairs.

C-6′ repairs were completed on 1937. At the end of April she departed Cartagena to make her third deployment of the war to the Cantabrian Sea along Spain's northern coast. She rendezvoused with C-2 and C-4 at the Port of El Musel at Gijón, then moved on to Santander, where she arrived on , and Bilbao, which she reached on . Aircraft of the German Condor Legion attacked her at Bilbao, extensively damaging her and killing six and wounding three members of her crew. She underwent repairs at Sestao until 1937.

C-6 departed Bilbao in company with C-4 on 1937 and reached Santander on without encountering any Nationalist ships. A new Soviet Navy officer reported aboard to relieve her commander, but both Soviet officers remained aboard when she got underway from Santander on 1937 to attack Almirante Cervera off Cantabria. On the night of 1937 C-6 approached Almirante Cervera on the surface and fired two torpedoes, both of which malfunctioned: The first veered off course and began circling C-6, while the second torpedo went into a steep dive and exploded upon hitting the seabed.

C-6′s new Soviet commanding officer took her out on numerous patrols, during which C-6 sighted Almirante Cervera but could not close for an attack. On the night of 1937 C-6 sighted the Nationalist heavy cruiser and fired two torpedoes at her, both of which missed.

With the fall of Santander to Nationalist forces imminent, C-6, C-2, and C-4 left Santander in August 1937, evacuating Republican military personnel and politicians. C-6 also embarked Soviet staff and treasure worth 15 million pesetas at the time.

After Nationalist warships bombarded the Port of EL Musel at Gijón at the end of August 1937, C-2 and C-4 fled to ports in France. Damage forced C-6 to remain behind. When she finally left port she encountered the Nationalist minelayer Jupiter on 1937 and fired two torpedoes at her. One torpedo was deflected and missed, and the other one sank.

C-6 returned to Gijón. Just before Gijón fell to Nationalist forces, Nationalist warships again bombarded the port, and C-6 sustained damage that prevented her from submerging. To prevent her capture by the Nationalists, her crew took her out of the harbor and scuttled her on 1937 in waters deep. Torpedo Boat No. 3 rescued her crew, and her Soviet officers withdrew from Gijón by air. The Spanish Civil War continued until 1939, when it ended in a Nationalist victory and the establishment of Francoist Spain.

Final disposition

The wreck of C-6 was refloated in November 1947 and taken under tow to the Port of El Musel at Gijón. The tow failed en route, and C-6 sank again.

Notes Citations

Bibliography ABC (newspaper, in Spanish)

La Vanguardia newspaper (in Spanish)