On 3 June 1779, in an attempt to achieve a strategic advantage by misleading the British, the French fleet at Brest left port hastily and sailed southward, deliberately under-provisioned in order to avoid Royal Navy scrutiny and a subsequent blockade.

Because the French fleet had deliberately departed from Brest before they were fully supplied, numerous problems quickly arose as the wait for the Spanish forces dragged out to several weeks.

[5] It was not until 22 July that the Spanish fleet finally arrived, commanded by Don Luis de Córdova, who was to be subordinate to d'Orvilliers in the joint enterprise.

The goal of the combined fleet was to put the Royal Navy out of action so that the allied army could be safely transported across the English Channel, (La Manche), and set up a base on either the Isle of Wight or the nearby British coast.

At the time there were fewer than 40 Royal Navy ships of the line available in the English Channel area, under the command of the ailing 64-year-old Sir Charles Hardy, who had been desk-bound for 20 years.

Having missed opportunities to seize two important British convoys of merchant ships from the West Indies, which reached Plymouth on 31 July, the Armada finally passed Ushant on 11 August and entered the Channel.

On 16 August the French and Spanish ships, which were sailing slowly eastwards up the Channel, received orders from France to turn around, as it had been decided by the government that the best place for the troops to land would be near Falmouth in Cornwall.

It prevented them from bringing their full force to bear on Gibraltar, which had strengthened its defences after weak early attacks and was able to successfully hold out until the end of the war.

Keeping so many ships at sea and so many troops waiting at embarkation ports for months on end was hugely expensive, and many sailors died of disease.

The French and Spanish fleets continued joint operations afterward, primarily against isolated British garrisons in order to protect troop landings, rather than as a direct challenge to the Royal Navy.