The operation was successful. The Spaniards, finding their line of communication threatened, advanced in force from their position by the sea, and their forts opened a heavy fire on the little work thrown up. Other similar attempts would have been made to harass the Spaniards and divert them from their main work, had not Sir Francis Vere been severely wounded in the head on the 4th of August by a shot from the Spanish batteries, which continued to keep up a tremendous fire upon the town. So serious was the wound that the surgeons were of opinion that the only chance of saving his life was to send him away from the din and turmoil of the siege; and on the 10th he was taken to Middelburg, where he remained for a month, returning to Ostend long before his wound was properly healed.

On the 1st of August a batch of recruits had arrived from England, and on the 8th 1200 more were landed. The fire of the besiegers was now so heavy that the soldiers were forced to dig underground quarters to shelter themselves. Sir Horace Vere led out several sorties; but the besiegers, no longer distracted by the feints contrived by Sir Francis, succeeded in erecting a battery on the margin of the Old Haven, and opened fire on the Sand-hill Fort.