On 27 July, the Armada anchored off Calais in a tightly packed defensive crescent formation, not far from Dunkirk, where Parma's army, reduced by disease to 16,000, was expected to be waiting, ready to join the fleet in barges sent from ports along the Flemish coast. Communication was more difficult than anticipated, and word came too late that the Parma army had yet to be equipped with sufficient transport or to be assembled in the port, a process that would take at least six days. As Medina Sidonia waited at anchor, Dunkirk was blockaded by a Dutch fleet of 30 flyboats under Lieutenant-Admiral Justinus van Nassau. Parma wanted the Armada to send its light pataches to drive away the Dutch, but Medina Sidonia would not send them because he feared he would need these ships for his own protection. There was no deep-water port where the fleet might shelter, which had been acknowledged as a major difficulty for the expedition, and the Spanish found themselves vulnerable as night drew on.