Vessels that are 65.6 feet or longer are required to carry both a whistle or horn and a bell on federally controlled waters. This is a safety regulation to ensure proper communication and navigation. Other vessel types, such as PWCs and sailboats, do not have this specific requirement. ;
Vessels that are 65.6 feet or more in length are required to carry both a whistle or horn and a bell on federally controlled waters, according to USCG regulations. This requirement ensures safety and effective communication among vessels. Therefore, the correct answer is D: vessels 65.6 feet or more in length.
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