S.C. Code Ann. § 54-3-840

The Authority may levy and collect from all vessels entering into and using the port of Charleston such fees and harbor or port charges, not inconsistent with the law, as, in its discretion, may be necessary to pay the harbor master and port wardens for the services required of them and to defray the necessary expenses attendant upon the execution of the duties devolved upon it under this article in relation to the regulations for the safety and convenience of vessels entering said port and waters, or any of them.