Sec. 12.5. Notwithstanding sections 10, 11, and 12 of this chapter, any exemption to the motorboat speed limit that was:
(1) granted by the department in response to a petition from a majority of abutting property owners; and
(2) in effect on August 31, 1985;
remains in effect. However, if a majority of abutting property owners petition the department to rescind or amend the exemption, the department may rescind or amend the exemption.