There should have been enough for three months. [fact]
Every available cask and butt had been filled at Corunna; there should have been enough for three months. But again casks leaked, and some when opened held no more than a few inches of green slime. It was now seen how deadly was the blow that Drake had struck at Cape St Vincent. With a long hard voyage ahead squadron after squadron reported only enough water to last, with the severest rationing, for a month or less.
Garrett Mattingly, The Defeat of the Spanish A…, loc. 821