The following is from The Phinney Site (http://www.history.navy.mil/branches/org12-7l.htm)
On the night of 15 August, American General Solomon Lovell appeared aboard Providence and informed the naval officers that Saltonstall needed assistance to tow the Warren upriver. News that the flagship had not yet been destroyed invigorated the men, and numerous boats were promptly manned and sent down to Oak Point. Despite such good tidings, the privateer crews began scuttling their vessels during the early morning hours of August 16. The first vessel to be destroyed was the transport Pigeon, followed shortly thereafter by Hector and Black Prince. Monmouth exploded as flames from Black Prince reached its deck guns and powder stores. A few hours later, a messenger arrived from Oak Point with news that the Warren had been set ablaze on Saltonstall’s orders and was already consumed. The same fate befell the privateers downriver. With no other option left to them, the officers and crew of the remaining ships abandoned their craft and set them on fire. Since most were “half a pistol shot” or less apart, the flames rapidly spread from one vessel to another. By late afternoon 16 August, the river near Bangor was filled with the smoldering hulks of ships that had either exploded or burned to the waterline and slipped beneath the water. Only forty-eight hours after Collier’s British squadron arrived at the mouth of Penobscot Bay, most of the American fleet lay in ruins along the course of the river.