Miss. Code § 27-31-49
The board of supervisors of any county bordering on the Gulf of Mexico with a population in excess of one hundred sixty thousand (160,000) according to the 1990 federal decennial census, or the governing authority of any municipality located in any such county, is hereby authorized and empowered to exempt all itinerant vessels within such a county or municipality from ad valorem taxation. As used in this section, "itinerant vessel" means vessels engaged in interstate commerce which are temporarily docked at a state port organized pursuant to Section 59-5-1, et seq., Mississippi Code of 1972, but shall not include any cruise vessel or vessel upon which legal gaming is conducted pursuant to the Mississippi Gaming Control Act.
Miss. Code § 27-31-49