It being now thought impossible to prevent the fleet from passing Fort Moultrie, and taking such stations in Cooper river as would enable them to rake the batteries on shore, and to close that communication between the town and country, the plan of defense was once more changed, and the armed vessels were carried into the mouth of Cooper river, and sunk in a line from the town to Shute's Folly. This was the critical moment for evacuating the town. The loss of the harbor rendered the defense of the place, if not desperate, so improbable, that the hope to maintain it could not have been rationally entertained by a person who was not deceived by the expectation of aids much more considerable than were actually received. When this state of things was communicated to Washington by Lieutenant-Colonel Laurens he said in reply: "The impracticability of defending the bar, I fear, amounts to the loss of the town and garrison. At this distance it is impossible to judge for you. I have the greatest confidence in General Lincoln's prudence, but it really appears to me that the propriety of attempting to defend the town depended on the probability of defending the bar, and that when this ceased, the attempt ought to have been relinquished. In this, however, I suspend a definitive judgment, and wish you to consider what I say as confidential." Unfortunately this letter did not arrive in time to influence the conduct of the besieged. On the 4th of April (1780), Admiral Arbuthnot, taking advantage of a strong southerly wind and a flowing tide, passed Fort Moultrie [2] and anchored just without reach of the guns of Charleston. The fort kept up a heavy fire on the fleet while passing which did some damage to the ships and killed or wounded twenty-seven men. On the 29th of March the royal army reached Ashley river and crossed it ten miles above the town without opposition, the garrison being too weak to dispute the passage. Sir Henry Clinton having brought over his artillery, baggage, and stores marched down Charleston Neck, and on the night of the 1st of April, broke ground at the distance of 800 yards from the American works. The fortifications of Charleston were constructed under the direction of Mr. Laumoy, a French engineer of reputation in the American service, and, although not calculated to resist a regular siege, were by no means contemptible; and Clinton made his approaches in due form. Meanwhile the garrison received a reinforcement of 700 Continentals under General Woodford, and, after this accession of strength, amounted to somewhat more than 2,000 regular troops, besides 1,000 militia of North Carolina, and the citizens of Charleston.