With only 400 men at their command, and without sufficient artillery the American attempt to capture the battery failed. The firepower of the British defense proved to be too much and the Americans were forced to pull back.The British sent for reinforcements, and given their control of the area, those reinforcements arrived on August 12. On that fateful day, British Commodore Sir George Collier entered the bay and forced the Americans to turn and flee further into the bay. As a result, the Americans were trapped between the British fleet and fort.
Knowing the situation to be hopeless, the Americans burned their ships and fled inland. The British sustained comparatively few casualties: 25 dead, 35 wounded, 26 taken prisoner. The Americans, on the other hand, lost 474 plus all of their vessels. Commodore Saltonstall was court-martialed and removed from command while the British remained in possession of the area until the end of the war.