During the year between his return from Paris and his present appointment, he had laid before the Admiralty two papers, containing an admirable summary of the leading strategic conditions of the whole scene of war in the western hemisphere, with suggestions for action amounting to a plan of campaign. One feature of this was based upon the weather differences, which rendered cruising dangerous in the West Indies when most favorable to the northward, and unsure in North America when most certain among the islands. He proposed to utilize this alternation of seasons, by shifting a mobile reinforcement suddenly and secretly from one end to the other of the long front of operations. This is a common enough expedient in military art, but had rarely received the convincing formulation which he gave it; while that such a conception was a novelty to the average naval mind of the day, may be inferred from the startled wrath of the admiral in North America at Rodney’s unexpected intrusion upon his bailiwick.
Sandwich, however, had entertained the project, and in October, 1779, just as Rodney’s appointment issued, a vessel sailed from England with letters to Admiral Arbuthnot in New York, directing him to send several ships-of-the-line to the West Indies for the winter campaign. The vessel lost a mast, kept off to Nassau in the Bahamas, and after arrival there her captain, while spending some months in repairs, did not think to send on the despatches. Arbuthnot, therefore, received them only on March 16, 1780; too late, doubtless, to collect and equip a force in time to reach Rodney before the affair of April 17th.
At the end of July, 1780, the conditions in the West Indies were that the allied French and Spanish fleets had gone to leeward from Martinique; to Havana, and to Cap Francois, in Hayti. At the latter port was assembling a large trade convoy—three hundred ships, according to Rodney’s information. He reasoned that this must go to Europe, but would not require the full strength of the French fleet; therefore, transferring his own insight to the enemy’s mind, he convinced himself that a part of their vessels would seek Narragansett Bay, to reinforce the seven ships-of-the-line that had reached there on July 12th, under De Ternay, of whose arrival Rodney now knew. Great possibilities might be open to such a combination, skilfully handled against the inferior numbers of Arbuthnot. “As it plainly appeared to me that His Majesty’s territory, fleet, and army, in America were in imminent danger of being overpowered by the superior force of the public enemy, I deemed it a duty incumbent upon me to forego any emoluments that might have accrued by the enterprise intended by General Vaughan and myself during the hurricane months, and without a moment’s hesitation flew with all despatch possible to prevent the enemy’s making any impression upon the continent before my arrival there.” The protestation of disinterestedness here is somewhat intrusive, and being wholly unnecessary excites rather criticism than confidence.