The British did not attempt to take the fort again . Within days of the battle , Charlestonians learned of the signing of the Declaration of Independence in Philadelphia . The British troops were reembarked on their transports , and on July 21 the British fleet withdrew northward to help the main British army in its campaign against New York City . To add insult to injury , one of the British transports grounded off Long Island and was captured by Patriot forces .