The Continental Army repossessed Philadelphia after the British evacuated, and General Washington sent General Duportail to Congress on June 30, 1778, with a letter recommending securing the Delaware River against enemy assaults.13 He also gave the general and principal engineer ample instructions, but seven weeks later, Congress still had not read the instructions. General Duportail was soon called away, and Colonel Jean Baptiste Joseph, Comte de Laumoy, was left in charge of the works. Congress paid very little attention to the matter. President Laurens wrote to the governor of South Carolina on August 11,
Immediately after we had repossessed this city, General Washington, in the spirit of a wise and watchful Commander-in-Chief, sent General Duportail with a letter to Congress recommending the immediate securing the river against Assaults from the Enemy, and for that purpose gave the General, who is principal engineer, ample instructions. We have been here upwards of 7 weeks & I have repeatedly urged Congress to hear the instructions read, yet to this moment no step is taken.14
The French fleet of ten ships of the line and three frigates under Admiral Comte Jean Baptiste Charles Henri Hector d’Estaing (1729–1794) was badly damaged in a hurricane on August 11, 1778, while they were attempting to engage the British fleet off the coast of Rhode Island. The British fleet went to New York to refit, while the French fleet departed Newport on August 21 for Boston for repairs. Duportail thought the British might attempt to block the port of Boston with a fleet and to embark troops at New York to go to Rhode Island, where they would debark and march directly toward Boston. He recommended ordering General John Sullivan to take all the necessary measures to hinder their debarkation; to reconnoiter positions to be occupied on the route to Boston; to have cut up, or hold himself ready to cut up, all parallel and detour roads leading there; and to fortify any place that could be favorable to fighting the British Army. He also recommended sending three thousand to five thousand men toward the Connecticut River to be ready to cross to reinforce General Sullivan. He also suggested that he (Duportail) go immediately “to General Sullivan’s army to assist in choosing and fortifying a good position on the route to Boston. When that should be done—That I should go myself to Boston to see what may be done for the defence of the town itself.”15
Soon afterward, General Duportail was sent to oversee the works on the Hudson with the following orders:
Head Quarters, White Plains,
27 Augst. 1778
Sir,
You will proceed as speedily as possible to the Highlands and examine the several fortifications carrying on there for the defence of the North River. When you have done this, you will make me a full report of their state and progress, with your opinion of any alterations or additions which may appear to you necessary in improvement of the present plan. In doing this you will of course, consider the labor and expense which have been already incurred, the advanced season of the year & the resources of the country for carrying any plan which may be formed into execution.
It is my wish you should also take measures without delay for executing the instructions given you the [thirtieth] of June last relative to a plan for the defense of the River Delaware and the City of Philadelphia.—In performing which you will also view the Subject in a maritime point of light; in order as far as natural circumstances will permit, to provide a secure Port capable of excluding the enemy’s vessels and receiving or protecting our own or those of our allies.—To this end you will make such arrangements as the good of the service and the state of your department will best warrant.16
General Washington wrote to Colonel William Malcom on September 7, advising him that he was ordering Duportail to visit the posts in the Highlands to examine the state of the fortifications there. Duportail arrived two days later and examined all the works, then went to Windsor with Colonel Malcom on the eleventh to view the chevaux-de-frise.
Chevaux-de-frise were used to block passageways and to serve as obstructions of troop movement on the battlefield. Photo courtesy of the author.
DUPORTAIL’S SURVEY OF THE WEST POINT DEFENSES
Duportail submitted the following report dated August 13, 1778 (it should be September 13, as his orders to undertake a survey of West Point defenses were issued on August 27, and he arrived on September 9):
The Works which are in hand at West Point and some inconsiderable ones, which it is necessary to add to them, will, with the help of the chain, perfectly fulfill the object which is proposed,—that of hindering the enemy’s remounting the North River.
Fort Putnam, which is as it were, the key of all the others may be rendered almost impregnable. There is indeed a height, which commands it, but besides that this height may be taken possession of with a redoubt, it would be very difficult for an enemy, even when master of it to bring heavy cannon there. Besides it would be too far to make a breach. This fort has nothing to fear but a bombardment or escalade with respect to a bombardment, the mean(s) to make it ineffectual is to have bomb-proofs sufficient for three fourths of the Garrison, magazines, hospital, etc.—I am told Col. Koshucsko proposes, at this time to begin one; but which will not suit more than 70 or 80 men. This is far from sufficient. There must be another, the place and size of which, I have pointed out to the Captain who conducts the works.—It will contain about two hundred men—with respect to the escalade, to prevent its success, the side of the fort which looks towards the river and is the most accessible, as well as that which looks towards Fort Arnold, must
