A British fleet under Admiral Sir George Rodney defeated a Spanish squadron under Don Juan de Lángara.

In a running battle that lasted from mid-afternoon until after midnight, the British captured four Spanish ships, including Lángara's flagship Real Fénix (often just called "Fenix").

One of Spain's principal goals upon its entry into the American War of Independence in 1779 was the recovery of Gibraltar, which had been lost to Great Britain in 1704.

[6] The Spanish planned to retake Gibraltar by blockading and starving out its garrison, which included troops from Britain and the Electorate of Hanover.

[9] A supply convoy was organized, and in late December 1779 a large fleet sailed from England under the command of Admiral Sir George Rodney.

Although Rodney's ultimate orders were to command the West Indies fleet, he had secret instructions to first resupply Gibraltar and Minorca.

The entire convoy was captured, with the lone ship of the line, Guipuzcoana, striking her colours after a perfunctory exchange of fire.

On 16 January the fleets of Lángara and Rodney spotted each other around 1:00 pm south of Cape St. Vincent, the southwestern point of Portugal and the Iberian Peninsula.

Lángara started to establish a line of battle, but when he realised the size of Rodney's fleet, he gave orders to make all sail for Cadiz.

[14] Because of their copper-sheathed hulls (which reduced marine growths and drag), the ships of the Royal Navy were faster and soon gained on the Spanish.

Although Captain Young is credited in some accounts with pushing Rodney to do so, Gilbert Blane, the fleet physician, reported it as a decision of the council.

Around 11:00 pm San Eugenio surrendered after having all of her masts shot away by HMS Cumberland, but the difficult seas made it impossible to board a prize crew until morning.

[5] With the arrival of daylight, it was clear that the British fleet and their prize ships were dangerously close to a lee shore with an onshore breeze.

[4] The supply convoy sailed into Gibraltar on 19 January, driving the smaller blockading fleet to retreat to the safety of Algeciras.

The wounded Spanish prisoners, who included Lángara, were offloaded there, and the British garrison was heartened by the arrival of the supplies and the presence of Prince William Henry.

[23] After also resupplying Minorca, Rodney sailed for the West Indies in February, detaching part of the fleet for service in the Channel.

He distinguished himself for the remainder of the war, notably winning the 1782 Battle of the Saintes in which he captured French Admiral François Joseph Paul de Grasse.

)[31] Rodney's observations on the benefits of copper sheathing in the victory were influential in British Admiralty decisions to deploy the technology more widely.

[34] Beatson also fails to list a number of frigates, including Apollo, which played a key role in the capture of Monarca.