It's the Law

Sound-Producing Devices


All vessels are required to carry an efficient sound-producing device, such as a whistle or horn, that is audible for at least one-half mile. Larger vessels also may be required to carry a bell or gong per federal Navigation Rule # 33, which can be found at http://www.navcen.uscg.gov/?pageName=NavRulesWithAnnexes.

Sound Signals

Some common sound signals that you should be familiar with as a recreational boater are as follows.

Changing Direction

  • One short blast tells other boaters, "I intend to pass you on my port (left) side."
  • Two short blasts tell other boaters, "I intend to pass you on my starboard (right) side."
  • Three short blasts tell other boaters, "I am operating astern propulsion." For some vessels, this tells other boaters, "I am backing up."

Restricted Visibility

  • One prolonged blast at intervals of not more than two minutes is the signal used by power-driven vessels when underway.
  • One prolonged blast plus two short blasts at intervals of not more than two minutes is the signal used by sailing vessels.

Warning

  • One prolonged blast is a warning signal (for example, used when coming around a blind bend or exiting a slip).
  • Five (or more) short, rapid blasts signal danger or signal that you do not understand or that you disagree with the other boater's intentions.