Confident that the British fleet, thus augmented, would attempt every thing for the relief of Lord Cornwallis, De Grasse expected to be attacked by a force not much inferior to his own.

Thinking his station within the Chesapeake unfavourable for a naval combat, he designed to change it, and communicated to General Washington his intention to leave a few frigates to block up the mouths of James and York Rivers, and to put to sea with his fleet in quest of the British.

If they should not have left the harbour of New York, he purposed to block them up in that place; supposing that his operations in that quarter would be of more service to the common cause, than his remaining in the bay, an idle spectator of the siege of York.
The Commander-in-chief was much alarmed at this communication.

Should the admiral put to sea, the winds and many accidents might prevent his return to the Chesapeake.

During his absence, a temporary naval superiority might be acquired by the British in those waters, and the army of Lord Cornwallis might be placed in perfect security.