The Spanish coup of July 1936 dealt a severe blow to the structure of the Spanish Republican Armed Forces, which ended up fragmented on the basis of joining the rebels or remaining loyal to the established government.
The failure of the coup, especially in the main cities, Madrid, Barcelona, Bilbao and Valencia, along with the collapse of authority and the lack of agreement in the first brief negotiations, were only some of the factors that made the conflict drift towards open war.
José Giral's government tried to put together a Volunteer Army based on the units that had remained loyal, but the urgency of the moment played in favor of the formation of popular militias that were armed by parties and trade unions.

The main naval bases of the Spanish Republican Navy were Ferrol (Northern Coast), Cádiz (Southern Coast) and Cartagena (Eastern Coast).
The takeover of the Navy by coup leaders failed mainly because the messages calling for a rebellion against the Spanish Republic were not sent in code, as would have been the norm, from Ciudad Lineal to the senior officers commanding the ships.
A young Navy radiotelegrapher, Benjamín Balboa, later took credit for the news leak.

As a result, most crews in naval ships were alerted and took over the command, overwhelming their officers.
Thus, most of the ships of the Spanish Navy remained loyal to the republic, but many of the experienced top officers had been imprisoned and some were killed during the mutinies, a fact that hampered the efficiency of the loyalist navy.

The rebellion, however, was successful in wide areas of Northern and Southern Spain and the important bases of Ferrol and Cádiz would fall into rebel hands.
Warships that were in the dockyard, including heavy cruiser Canarias that was under construction at Ferrol, were seized and hastily put into use.
Cádiz was taken for the rebels with the help of the first troops from the Army of Africa.

Despite the fact that the greater part of the Spanish coast was on the republican side and despite the great number of naval units belonging to the Spanish Republican Navy, there was a lack of effective action in the first, decisive weeks of the war.
Some of the most experienced commanders, such as Francisco Bastarreche, Pedro Nieto Antúnez, Francisco Núñez Rodríguez, Gabriel Pita da Veiga y Sanz, Francisco Regalado Rodríguez, Manuel Vierna Belando and the brothers Francisco and Salvador Moreno Fernández, had defected to the rebels.
In addition the crew committees (Comités de Buque) that had taken over the command of the ships were not able to deal with the high coordination that was required at the time.

Later in 1936, Republican Defence Minister Indalecio Prieto terminated the Comités de Buque as part of his sweeping reorganization of the Republican Armed Forces.

The Third Reich and Italian Fascist military provided decisive support for General Franco's fraction of the army, so that the Spanish Republican Navy was unable to keep the blockade of the Strait of Gibraltar.
Thus, on 5 August 1936, the so-called Convoy de la victoria was able to bring at least 2,500 men of the Army of Africa from Spanish Morocco to Peninsular Spain breaking the republican blockade.
From August 6 rebel transport ships crossed the Strait of Gibraltar, with the cover of Italian bombers and republican Churruca-class destroyer Alcalá Galiano was attacked and hit by Fascist aircraft while steaming back to Málaga.
Pro-Franco sources claim that she suffered 18 seamen killed and 28 wounded.

In August 7, the Jaime I and the cruiser Libertad shelled Algeciras and severely damaged rebel gunboat Eduardo Dato and armed trawler Uad Kert (ex-Castle-class naval trawler HMT Rother; ex-HMT Anthony Aslete) .
Shortly thereafter a Nazi German Junkers Ju 52 struck the Republican battleship Jaime I and Italian bombers began to harass the Republican fleet so that it could not longer prevent the passage of transport ships.
Furthermore, two German cruisers, Deutschland and Admiral Scheer patrolled the Strait on so-called non-intervention missions.

In addition, the United Kingdom
The Spanish coup of July 1936 dealt a severe blow to the structure of the Spanish Republican Armed Forces, which ended up fragmented on the basis of joining the rebels or remaining loyal to the established government. The failure of the coup, especially in the main cities, Madrid, Barcelona, Bilbao and Valencia, along with the collapse of authority and the lack of agreement in the first brief negotiations, were only some of the factors that made the conflict drift towards open war. José Giral's government tried to put together a Volunteer Army based on the units that had remained loyal, but the urgency of the moment played in favor of the formation of popular militias that were armed by parties and trade unions.
The main naval bases of the Spanish Republican Navy were Ferrol (Northern Coast), Cádiz (Southern Coast) and Cartagena (Eastern Coast). The takeover of the Navy by coup leaders failed mainly because the messages calling for a rebellion against the Spanish Republic were not sent in code, as would have been the norm, from Ciudad Lineal to the senior officers commanding the ships. A young Navy radiotelegrapher, Benjamín Balboa, later took credit for the news leak.
As a result, most crews in naval ships were alerted and took over the command, overwhelming their officers. Thus, most of the ships of the Spanish Navy remained loyal to the republic, but many of the experienced top officers had been imprisoned and some were killed during the mutinies, a fact that hampered the efficiency of the loyalist navy.
The rebellion, however, was successful in wide areas of Northern and Southern Spain and the important bases of Ferrol and Cádiz would fall into rebel hands. Warships that were in the dockyard, including heavy cruiser Canarias that was under construction at Ferrol, were seized and hastily put into use. Cádiz was taken for the rebels with the help of the first troops from the Army of Africa.
Despite the fact that the greater part of the Spanish coast was on the republican side and despite the great number of naval units belonging to the Spanish Republican Navy, there was a lack of effective action in the first, decisive weeks of the war. Some of the most experienced commanders, such as Francisco Bastarreche, Pedro Nieto Antúnez, Francisco Núñez Rodríguez, Gabriel Pita da Veiga y Sanz, Francisco Regalado Rodríguez, Manuel Vierna Belando and the brothers Francisco and Salvador Moreno Fernández, had defected to the rebels. In addition the crew committees (Comités de Buque) that had taken over the command of the ships were not able to deal with the high coordination that was required at the time.
Later in 1936, Republican Defence Minister Indalecio Prieto terminated the Comités de Buque as part of his sweeping reorganization of the Republican Armed Forces.
The Third Reich and Italian Fascist military provided decisive support for General Franco's fraction of the army, so that the Spanish Republican Navy was unable to keep the blockade of the Strait of Gibraltar. Thus, on 5 August 1936, the so-called Convoy de la victoria was able to bring at least 2,500 men of the Army of Africa from Spanish Morocco to Peninsular Spain breaking the republican blockade. From August 6 rebel transport ships crossed the Strait of Gibraltar, with the cover of Italian bombers and republican Churruca-class destroyer Alcalá Galiano was attacked and hit by Fascist aircraft while steaming back to Málaga. Pro-Franco sources claim that she suffered 18 seamen killed and 28 wounded.
In August 7, the Jaime I and the cruiser Libertad shelled Algeciras and severely damaged rebel gunboat Eduardo Dato and armed trawler Uad Kert (ex-Castle-class naval trawler HMT Rother; ex-HMT Anthony Aslete) . Shortly thereafter a Nazi German Junkers Ju 52 struck the Republican battleship Jaime I and Italian bombers began to harass the Republican fleet so that it could not longer prevent the passage of transport ships. Furthermore, two German cruisers, Deutschland and Admiral Scheer patrolled the Strait on so-called non-intervention missions.
In addition, the United Kingdom 
Spanish Republican Navy