S.C. Code Ann. § 50-21-85
No person shall operate any vessel displaying, reflecting or flashing a blue light unless a duly commissioned law enforcement officer is on board.
The operator of any vessel being approached by a vessel flashing a blue light shall stop or maneuver in such a way as to permit boarding, so far as possible without endangering his own vessel, and not begin normal movement again until directed by the law enforcement officer or until the vessel flashing a blue light has cleared the immediate area.
The operator of any vessel approaching any area where a vessel flashing a blue light is located or patrolling shall slow his vessel to a no wake speed and shall maintain such speed until clear of the area.
Any person violating the provisions of this section is guilty of a misdemeanor and upon conviction shall be punished as provided in Section 50-21-150.