The all-important question was where to direct it.

There were two principal courses, involving two views of naval strategy.

The one was to act against the allied fleet, whose defeat, if sufficiently severe, might involve the fall of William's throne in England; the other was to make the fleet subsidiary to the Irish campaign.

The French king decided upon the former, which was undoubtedly the proper course; but there was no reason for neglecting, as he did, the important duty of cutting off the communications between the two islands.

As early as March he had sent a large fleet with six thousand troops and supplies of war, which were landed without any trouble in the southern ports of Ireland; but after performing that service, the ships employed returned to Brest, and there remained inactive during May and June while the grand fleet under the Comte de Tourville was assembling.
During those two months the English were gathering an army on their west coast, and on the 21st of June, William embarked his forces at Chester on board two hundred and eighty-eight transports, escorted by only six men-of-war.