Unforeseen delays, many of them related to Drake's own fear of becoming embayed in the Bay of Biscay, led Drake to bypass Santander, where most of this refitting was under way.
He alleged unfavourable winds and turned to attack Corunna (Coruña) in Galicia.
It is not fully clear why, but he may have been motivated by a false contemporary legend that a tower in Corunna held a fabulous treasure of gold coins, or he may have just been looking for supplies.

Corunna was almost defenceless at the time of the attack.
To face the English Armada's 150 ships plus boats, and the soldiers in them, Corunna had one galleon (San Juan, with 50 cannons), two  galleys (Diana and Princesa, with 20 cannons each), and two other smaller ships (nao San Bartolomé with 20 cannons, and the unarmed urca Sansón and galeoncete (small galleon) San Bernardo).
 A combination of militia, hidalgos and the few available soldiers totalled 1,500 soldiers, most of them with little military training, except for seven companies of old tercios who happened to be resting in the city after their return from war.
It also had the medieval city walls, built in the 13th century.

Norreys took the lower town, inflicted 500 casualties, and plundered the wine cellars there, while Drake destroyed thirteen merchant ships in the harbour.
For the next two weeks the wind blew westerly, and while waiting for a change the English occupied themselves in a siege of Corunna's fortified upper town.
They launched three major assaults against the walls of the upper town, and tried to breach them with mines, but the vigorous defence by the regular Spanish troops, militia, and women of the city including Maria Pita and Inés de Ben forced the English back with severe losses.(2018: pp.77–97)
The Princesa and the Diana managed to avoid capture and slip past the English fleet repeatedly to resupply the defenders.
After 14 days of siege and attempted assaults, on the 18th, the English heard news about Spanish reinforcements on their way to Corunna, and at length, with a favourable wind returning and painfully low morale, the English abandoned the siege and retreated to their ships, having lost four captains, three large ships, various boats and more than 1,500 men in the fighting alone, along with 3,000 other personnel in 24 of the transports.
This included many of the Dutch who found reasons to return to England or put into La Rochelle.(2018: pp.77–97)
The next step in Elizabeth's plan was to stir a Portuguese uprising against King Philip.
The Portuguese aristocracy had recognised him as King of Portugal in 1580, adding the Kingdom of Portugal to the Hispanic Monarchy.
The pretender to the throne that England supported, the Prior of Crato, was not an ideal candidate.
He did not have enough support even to establish a government in exile, nor much charisma to back his already dubious claim.
Elizabeth had agreed to help him in hopes of diminishing the power of the Spanish Empire in Europe, and in exchange for a permanent military base in the strategic Azores Islands from which to attack merchant ships and ultimately obtain control of the commercial routes to the New World.
Unforeseen delays, many of them related to Drake's own fear of becoming embayed in the Bay of Biscay, led Drake to bypass Santander, where most of this refitting was under way. He alleged unfavourable winds and turned to attack Corunna (Coruña) in Galicia. It is not fully clear why, but he may have been motivated by a false contemporary legend that a tower in Corunna held a fabulous treasure of gold coins, or he may have just been looking for supplies.
Corunna was almost defenceless at the time of the attack. To face the English Armada's 150 ships plus boats, and the soldiers in them, Corunna had one galleon (San Juan, with 50 cannons), two  galleys (Diana and Princesa, with 20 cannons each), and two other smaller ships (nao San Bartolomé with 20 cannons, and the unarmed urca Sansón and galeoncete (small galleon) San Bernardo).  A combination of militia, hidalgos and the few available soldiers totalled 1,500 soldiers, most of them with little military training, except for seven companies of old tercios who happened to be resting in the city after their return from war. It also had the medieval city walls, built in the 13th century.
Norreys took the lower town, inflicted 500 casualties, and plundered the wine cellars there, while Drake destroyed thirteen merchant ships in the harbour. For the next two weeks the wind blew westerly, and while waiting for a change the English occupied themselves in a siege of Corunna's fortified upper town. They launched three major assaults against the walls of the upper town, and tried to breach them with mines, but the vigorous defence by the regular Spanish troops, militia, and women of the city including Maria Pita and Inés de Ben forced the English back with severe losses.(2018: pp.77–97)
The Princesa and the Diana managed to avoid capture and slip past the English fleet repeatedly to resupply the defenders. After 14 days of siege and attempted assaults, on the 18th, the English heard news about Spanish reinforcements on their way to Corunna, and at length, with a favourable wind returning and painfully low morale, the English abandoned the siege and retreated to their ships, having lost four captains, three large ships, various boats and more than 1,500 men in the fighting alone, along with 3,000 other personnel in 24 of the transports. This included many of the Dutch who found reasons to return to England or put into La Rochelle.(2018: pp.77–97)
The next step in Elizabeth's plan was to stir a Portuguese uprising against King Philip. The Portuguese aristocracy had recognised him as King of Portugal in 1580, adding the Kingdom of Portugal to the Hispanic Monarchy. The pretender to the throne that England supported, the Prior of Crato, was not an ideal candidate. He did not have enough support even to establish a government in exile, nor much charisma to back his already dubious claim. Elizabeth had agreed to help him in hopes of diminishing the power of the Spanish Empire in Europe, and in exchange for a permanent military base in the strategic Azores Islands from which to attack merchant ships and ultimately obtain control of the commercial routes to the New World.
English Armada