US lawFederal (United States)RegulationsTitle 46 CFR — ShippingChapter I — COAST GUARD, DEPARTMENT OF HOMELAND SECURITYPart 131 — OPERATIONSSubpart I — Miscellaneous131.96546 C.F.R. § 131.965Sounding of whistle.Last amended: 2016Year: 2026Length: 18 wordsOfficial source Cite as 46 C.F.R. § 131.965 (2026)No vessel may sound its whistle within any harbor limits of the United States unless it needs to.Previous46 C.F.R. § 131.960Next46 C.F.R. § 131.970