Júpiter - class minelayer Júpiter - Class minelayers was a group of four vessels of the Spanish Republican Navy built during the Spanish Republic . Three of them came into service during the Civil War after joining the rebel side . Operational history . Civil War . The minelayers were commissioned by the Government of the Republic to SECN shipyards at Ferrol in 1935 , a year before the start of the Spanish Civil War . The first three ships of the class were seized by the insurgents and served in the rebel fleet . Their first deployment was the blockade of Bilbao . Due to the lack of destroyers in the Franco ’ s fleet , and the potential of their armament , the main mission of these vessels was not minelaying , but to face Government units in open combat , despite their slow speed . " Júpiter " . Along with " Vulcano " , the " Jupiter " was one of the main players in the blockade of international shipping in the ports of Biscay , where she took part in the capture of several merchantmen , especially the British " Candleston Castle " , " Dover Abbey " and " Yorkbrook " , the French " Cens " and a number of Basque Auxiliary Navy trawlers during the second half of 1937 . She also laid four minefields off Santander and Gijon , from April to July 1937 . The rebel battleship " España " was lost on 30 April after hitting by accident one of her mines at Santander . There were only four casualties among " España " ` s crew . On 17 July , while on patrol off Gijon , the " Júpiter " caught two British cargo ships while they were attempting to run the blockade . One of them , the " Sarastone " , managed to reach the harbor despite being firing on . The other steamer , " Candleston Castle " , stopped after the minelayer fired two shots across her bows . She was handed over by the " Júpiter " to the auxiliary cruiser " Ciudad de Palma " , which escorted the captured merchantman to Ferrol . A fruitless sortie was launched from the French port of Saint Jean de Luz by the Royal Navy ' s battleship HMS " Royal Oak " and the destroyer HMS " Basilisk " . She engaged the Basque Auxiliary Navy destroyer " Císcar " on 10 August off Gijon . During this exchange of fire , the " Júpiter " guns accidentally straddled the British destroyer HMS " Foxhound " . Occasionally , she also provided support fire for the rebel troops inland . On 24 August 1937 , after the fall of the port of Santoña , the " Júpiter " along with other naval units was called from Bilbao to watch the British steamer " Seven Seas Spray " , taken in custody by Nationalist troops while attempting to evacuate Basque troops as part of the ill - fated Santoña Agreement between the Italian Corpo Truppe Volontarie and the Basque Nationalist Party . On 5 October , while she was escorting the seized freighters " Dover Abbey " and " Yorkbrook " to Ribadeo , the former vessel sent a distress message to HMS " Resolution " , giving the position and course of the convoy and claiming that her capture had taken place outside territorial waters . Actually , they have been caught by armed trawlers off shore , well inside Spanish maritime boundaries . The " Júpiter " successfully outran the British battleship and the convoy reached destination without incident . At least five minor vessels carrying refugees and soldiers of the Republican army where seized by the minelayer after the fall of the last government ' s strongholds on northern Spain by the end of October . On Christmas Day 1937 she shelled the port of Burriana , near Castellon , in the Mediterranean coast , where the British freighter " Bramhill " was at anchor . The merchant was hit by several rounds and had to withdraw to Marseille to undergo repairs . Towards the end of the war , along with the auxiliary cruiser " Mar Negro " , she supported the landing an Infantry division on Mahón , Minorca , after the Republican surrender of this island , on 9 February 1939 . She was one of the units involved in the blockade of Alicante , where thousands of refugees gathered in order to flee Spain when Franco ' s victory was in sight . Her sister " Marte " , commissioned a few months before , took part in one of the last international maritime incidents of the war on 19 March 1939 , when she prevented the British steamer " Stanbrook " from entering Alicante . The ship , chartered by the Republican government , went back to Oran , Algeria . The " Stanbrook " eventually reached the Spanish port on 27 March , after the Nationalist side displayed some indulgency toward the evacuation of refugees in return for the British recognition of Franco ' s legitimacy . Two days later , the " Stanbrook " left Alicante bound for Oran , crowded with at least 2 , 000 people , one of the last ships to either enter or flee Republican Spain . Her Welsh skipper , Captain Archibald Dickson , later killed during the sinking of his ship in World War II , is today remembered as a hero in Alicante . After the Spanish Civil War , in December 1940 , the " Júpiter " carried out an undercover reconnaissance mission around Gibraltar with Admiral Canaris , General Lang and a Spanish officer aboard . The goal was to gather intelligence about the British fortifications and boom defenses as a first step toward the proposed Operation Felix . " Vulcano " . The " Vulcano " temporarily blocked the entrance to Gijon of the British merchants " Stanray " and " Stangrove " . At the end of the war in the north she joined a naval squadron which drove back the steamers " Hillfern " , " Bramhill " , " Stanhill " and " Stanleigh " off Cape Peñas , seizing a number of small Republican vessels crowded with refugees in the process . During this period she shelled , without success , the British " Thorpebay " when this steamer entered the port of the Musel . Between the last months of 1937 and 1939 " Vulcano " was active in the Mediterranean , where she was part of the rebel fleet which bombarded Castellon , Burriana and Vinaroz on Christmas Day 1937 . She played a key role , along with her sisters ships , in ferrying troops after Franco ' s army reach the coast between Valencia and Barcelona on April 1938 . On 17 October 1938 , she seized the Soviet cargo ship " Katayama " , of 3 , 200 tons . She also played a secondary role in the capture of the Greek merchant " Victoria " by the auxiliary cruiser " Mar Cantábrico " and the British " Stangrove " by the gunboat " Dato " , in the final months of the civil war . All these freighters joined the Spanish merchant fleet at the end of the conflict . Perhaps the most famous action of " Vulcano " is the chase and capture of the Republican Churruca class destroyer " Jose Luis Diez " off Gibraltar , in the course of a battle fought as close as 50 meters between the ships involved . The " Diez " eventually became stranded in Catalan Bay , in territory of Gibraltar , the last day of 1938 . The destroyer was turned over to Franco ' s government after its recognition by Britain as the legitimate authority in Spain . She was the leading unit of an aborted landing at Cartagena on 7 March 1939 , after the withdrawal of the Republican fleet from its bases and its internment at Bizerte . The operation was mounted on the belief that anti - communist Republicans had taken over the port once the Government navy fled . However , loyalist forces retook control of the coastal batteries around the harbour . All the ships received the order of aborting the operation , but two transports , the Castillo de Olite and " Castillo Peñafiel " , deprived of radio , continued toward Cartagena undeterred . They were the former Soviet steamers " Postishev " and " Smidovich " , of 3 , 545 and 2 , 485 tn respectively , which had been seized by the Nationalists at high seas . The " Castillo de Olite " was sunk by a 381 mm battery close to the docks , with a loss of life of almost 1 , 500 . Meanwhile , the " Castillo Peñafiel " had a narrow escape , harassed by Republican aircraft . In a letter to General Franco , Admiral Francisco Moreno put the blame on " Vulcano " ´s commander for his failure to prevent the departure of the freighters , as ordered by Moreno himself . The " Vulcano " apparently gave green light to the transports after receiving contradicting orders from the high command to proceed . Along with the cruiser " Canarias " , " Vulcano " landed two infantry battalions at Alicante on 31 March , the day before the official end of hostilities . Refurbishment . Of the four vessels , only " Júpiter " and " Vulcano " took part in a modernization program after the agreements between Spain and the United States in the 1950s , and were reclassified as frigates . The modernization was held in Cartagena from 1958 to 1961 . The antisubmarine and antiaircraft weapons were updated by adding a squid multiple mortar and Bofors 40 mm gun s . The units were also fitted with radar . Both ships joined the frigate squadron along with those units of the first " Pizarro " class . " Júpiter " was written off the Navy list on 23 November 1974 , and " Vulcano " was used as a store ship from 12 March 1977 until her final decommissioning on 30 April 1978 , this being the last warship to be removed from service of those who participated in the Civil War . " Marte " and " Neptuno " remained unchanged until their decommissioning in 1971 and 1972 respectively .