In 1779 he went out to the West Indies, in command of four line-of-battle ships and seven frigates, to join the fleet of Count d’Estaing, off Martinique, and participated in the action of July 6th, between d’Estaing and Admiral Byron. The following year he took part, in the same latitude, in the three battles between the Count de Guichen and Admiral Rodney, after the last of which he returned to France. At the commencement of 1781 he was sent out with an important convoy, to Martinique. He sailed from Brest on March 24th, with twenty-three ships-of-the-line, carrying troops, and having on board a very large sum of money, and a quantity of arms and ammunition, all intended for the succor of the young and struggling Republic of the United States. On the twenty-eighth of April De Grasse arrived off Port Royal, Martinique, where he found eighteen English line-of-battle ships, detached from Admiral Sir George Rodney’s fleet, and under the command of Rear-Admiral Sir Samuel Hood, who was there to oppose the landing of the convoy at Martinique. Hood, recognizing the superior force of De Grasse, contented himself with distant firing, and did not attempt to engage; De Grasse chased him off to the westward of Saint Lucie, and then returned to Martinique Road with his convoy. Soon after he left there, to attack, in concert with the Marquis de Bouillé, the English island of Tobago; and, on June 1st obtained possession of the chief town of that island. De Grasse then sailed for San Domingo, took on board three thousand soldiers; touched at Havana, where he effected a loan; and then came through the Bahama Channel, a route not then used by large ships, to the American coast; which he followed up until he entered the Chesapeake. Here he, with his fleet, and in concert with General Washington, made the well known dispositions which led to the surrender of Cornwallis, at Yorktown. On September 5th, hearing of the approach of the English fleet, De Grasse left his anchorage in Lynnhaven Bay, just inside of Cape Henry, and put to sea. Bougainville commanded the van division of his fleet, in the Auguste, 80; De Grasse himself the centre, in the Ville de Paris, 104; and the Chevalier de Monteil the rear division, in the Languedoc, 80. The English fleet, of twenty line-of-battle ships, was commanded by Admirals Graves, Hood and Drake. A partial engagement followed, which was mostly confined to the van divisions of the two fleets, and which continued about two hours and a half. Four or five days were consumed in manœuvres, De Grasse not being able to bring Graves to a general engagement, and finally the French fleet returned to their anchorage in Lynnhaven Bay; having, on the return, captured two English frigates.