[Code of Federal Regulations] [Title 46, Volume 7] [Revised as of October 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR196.20-1] [Page 404] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 196_OPERATIONS--Table of Contents Subpart 196.20_Whistling Sec. 196.20-1 Unnecessary whistling prohibited. (a) The unnecessary sounding of the vessel's whistle is prohibited within any harbor limits of the United States.