S.C. Code Ann. § 50-21-87: Operation of vessel prohibited within fifty feet of vessel displaying diver down flag; diving prohibited within fifty feet of vessel whose occupant is fishing.

(A) A person may not operate a vessel within fifty feet of another vessel when a diver is displaying a diver down flag (red with a diagonal white stripe) to mark the location of the diver. When the flag is being displayed in a water body too narrow to allow passage of another vessel other than within fifty feet, a vessel operator may proceed only past the displayed flag at a no-wake speed and allowing as much clearance between his vessel and the displayed flag as is safe and practical.

(B) A person may not engage in diving activities within fifty feet of a vessel whose occupant is fishing.

(C) A person does not violate this section if he fishes or displays a dive flag in an area before another person subsequently engages in diving activities or operates a vessel within fifty feet of a displayed dive flag.