Red lights answered from the shore
The commander of the USS Pawnee passed on what the master of the Mayflower had seen four miles south of North Edisto: lights aboard a vessel inshore, answered from the beach by a number of red lights, and at daylight a steamer standing eastward burning black smoke. The blockade was broken every week by exactly this — a signal, a tide and a fast hull.
Official Records of the Navies, Series I, Vol. 14