Prior to the June 28, 1776 British attack on Fort Sullivan, American engineer Captain J. Ferdinand DeBraham served as the Chief Engineer for Colonel Moultrie and was tasked with building a useable bridge across the Sullivan’s Island Narrows Creek as an avenue of escape from Sullivan’s Island. It was considered at first to build a “bridge of boats,” but there were not enough boats to cover the distance of almost a mile. DeBraham then planned to build a “floating bridge” using empty hogsheads anchored by a series of hooks and clamps. After the hogsheads were in place, planks were installed across the floating hogsheads.
In order to test the floating bridge, Lt. Colonel Thomas Clark and 200 men marched from Haddrell’s Point to attempt to cross the bridge. The men were less than halfway across before the bridge started to sink. Fortunately, Clark and his men quickly withdrew before a catastrophe occurred. Frustrated, General Lee replaced DeBraham with Lt. Nicholas Massenburg in late June as a result of his failed bridge.
In September 1776, General Christopher Gadsden oversaw the construction of a new permanent bridge which took nine months to complete. The bridge had four arches built in the supports to allow for the free movement of the tides. It was said to be “3,517 feet long and wide enough for a dozen men to walk abreast.” One observer asserted there was “nothing like it on the continent.”
At the Haddrell’s Point side, a small redoubt was built on the causeway leading to the bridge. The number and size of guns is unknown. The causeway redoubt was approximately 150 yards from the mainland. After the fall of Lempriere’s Point Battery on April 28, the only fortifications controlled by Americans east of the Cooper River were the Gadsden Bridge Redoubt and Fort Moultrie. The redoubt was held by twenty men with the 1st South Carolina Regiment commanded by Captain John Williams.
On May 2, British Major Patrick Ferguson led sixty troops on an attack on the Gadsden Bridge Redoubt. Ferguson divided his men with one-half attacking from the right flank and the other attacking down the causeway at the center of the redoubt. The tide was so low that the troops approaching on the right flank were moving across dry land. The other British troops, led by Captain Abraham DePeyster, were approaching in knee-deep water. Williams’s men offered little resistance, but Ferguson’s men were under fire from guns at Fort Moultrie until dark. The capture of this redoubt now cut off all American communications with Fort Moultrie, leaving them isolated.