In addition to these works, several armed galleys and floating batteries were stationed in the river, all forming strong barriers against the fleet of the enemy. This circumstance troubled the British general, for he foresaw the consequences of having his supplies by water cut off, and the danger to which his army would be exposed in Philadelphia if unsupported by the fleet. Immediately after the battle at Brandywine, Earl Howe sailed down the Chesapeake, and entered the lower Delaware with several light vessels, among which was the Roebuck, commanded by Captain Hammond. That officer represented to General Howe, that if a sufficient force could be sent to reduce the fortifications at Billingsport, he would take upon himself the task of opening a passage for vessels through the _chevaux de frise, or stackadoes_, at that point. Howe readily consented to attempt the important measure. Two regiments, under Colonel Stirling, were dispatched from Chester, in Pennsylvania, for that purpose. They crossed the river a little below Billingsport, marched in the rear of the unfinished works, and made a furious assault upon the garrison. The Americans were dismayed at this unexpected attack, and believing themselves incompetent to make a successful defense, they spiked their cannons, set fire to the barracks, and fled. The English remained long enough to demolish the works on the river front; when Hammond, by the great exertions of his men, made a passage-way seventy feet wide in the _chevaux de frise_, and, with six vessels, sailed through, and anchored near Hog Island. Stirling returned to Chester, and, with another detachment, proceeded to camp, as an escort of provisions, bearing to General Howe intelligence of his success. [Illustration: 6302] Howe now determined to make a general sweep of all the American works on the Delaware, and, preparatory thereto, he called in his outposts and concentrated his whole army near to and within Philadelphia. Two Rhode Island regiments, belonging to General Varnum's *** brigade, under Colonel Christopher Greene, garrisoned the fort at Red Bank, and *So called in honor of Edward Byllinge, the purchaser of Lord Berkley's moiety of the province of New Jersey. Slight remains of this redoubt, it is said, yet remain. ** This cut, copied from an old print, shows the form of the chevaux de frisé. A is a profile view, and B a plan. The spikes were made of heavy timbers, about thirty feet in length. Partially filled with heavy stone, they presented a formidable obstacle to vessels. It is said that these obstructions were mainly planned by Dr. Franklin, and constructed under the immediate supervision of M. Du Plessis Manduit, a French engineer.