Rule 35 has the sound signals for vessels in or near restricted visibility, day or night. Learn the signals for your boat and for other vessels so you know what is approaching. There are also special signals for narrow channels, and the rules are slightly different for Inland and International waters.
Learn the sound signals for the waters in which you operate and have ready access to your boat’s horn. Remember, if you hear five short and rapid blasts on a boat’s horn or a ship’s whistle near you – look around! That’s the danger signal. Have a plastic reference card that lists the sound signals near the helm for quick reference. The text of the rules is available at www.navcen.uscg.gov/?pageName=navRulesContent.