In 1776, William Moultrie was second-in-command of Charleston, South Carolina's defenses. He was charged with construction of Fort Sullivan, which had been planned out in January 1776. Moultrie did not have stone available to construct the walls, so he used palmetto logs to build two parallel walls sixteen feet apart and filled in the gap with sand. At the time of the British arrival on June 2nd, only the south and east walls were complete. The new Southern Department Commander, Maj. General Charles Lee arrived a couple of days later on June 4th.
General Lee inspected the incomplete fort and felt that it should not be defended, but South Carolina Governor John Rutledge overruled him. Moultrie himself was also confident in the fort's capability. Meanwhile, Maj. General Henry Clinton landed on the adjacent Long Island, planning to ford the two islands and attack Fort Sullivan from that direction, but he was having difficulty crossing over. Moultrie ordered fortifications built there, so that even sending troops across by the few boats he had was now out of the question.
At 11:00 A.M., on June 28, 1776, Commodore Peter Parker began his bombardment of the fort with around 100 guns and the Battle of Fort Sullivan had begun. When three ships attempted to move into the harbor west of the fort, they got stuck on a shoal. Moultrie began a steady reply with his guns. The fort itself withstood the assault thanks to the spongy palmetto logs and the sand, which absorbed the cannon balls. Under his command that day were Lieutenant Thomas Sumter and Major Francis Marion. When General Lee visited the fort during the action, he was pleasantly surprised with how well the fort was withstanding the assault. The action ended at 9:30 P.M. and the beaten British ships slipped away at 11:00 P.M.