The Possession of the Port and Harbor of Charles Town having been thought an object of much importance to His Majesty's Service, and many different accounts having been received of the state of that Town, and the works carrying on by the Rebels in fortifying the Town, putting Fort Johnson in a posture of defence, and erecting a Fort of considerable strength on Sullivans Island, which commands the entrance of the Harbor; on the 16th May His Majestys Ship Sphinx with a small Schooner called the Pensacola Packet were dispatched from Cape Fear River, with instructions to sound the Bar and to reconnoitre the works on Sullivans Island, and in order to obtain the fullest information Capt [James] Moncrief of the Engineer Corps and one of the Lieutenants belonging to the Commodores Ship were directed to embark on board the Schooner.²