S.C. Code Ann. § 50-23-11
(A) Dealer demonstration numbers are limited to watercraft that are:
(B) The demonstration numbers must not be permanently attached to the vessel but must be on board at all times. Marine dealers who sell watercraft are allowed nine demonstration numbers. Marine dealers who only service watercraft or outboard motors are allowed one demonstration number.
If a dealer allows the operation of a watercraft with demonstration numbers, the dealer shall execute a form identifying the date and time, the specific watercraft, the dealer's permit number, the demonstration number, the purpose for which the watercraft is being operated and if for a prospective sale, the form must include the name of the prospective buyer, the date, the specific watercraft, the dealer's permit number, and the demonstration number. The form and the dealer demonstration number must be on board during operation but need not be attached. Operations with dealer demonstration numbers are limited to seventy-two consecutive hours. This form is not required of owners, employees, or corporate officers who carry dealer identification and who are authorized to use demonstration numbers as provided herein.