In one thing Drake was quite wrong: Medina Sidonia had express orders not to be diverted by any English offensive, but to sail for the Channel and his rendezvous with Parma no matter what Drake did. If Drake had relied on the alarm caused by his appearance in person on the coast of Spain to keep the Spanish fleet at home he might have missed the Armada altogether. … Like Santa Cruz he was prepared to sail to meet the enemy with thirty rounds of ammunition per gun. In the actual encounter the English had spent more than that before they had done the Armada any real damage.

Garrett Mattingly, The Defeat of the Spanish A…, loc. 588