It's the Law: Delaware Boating Regulations

9.2.4 Whistles and Bells.

9.2.4.1 A vessel of 12 meters (39.4 ft.) or more in length shall be equipped with a whistle and a bell. The whistle and bell shall comply with the specifications in Annex III to the Inland Navigation Rules (33 CFR Part 86). The bell may be replaced by other equipment having the same respective sound characteristics, provided that manual sounding of the prescribed signals shall always be possible.

9.2.4.2 A vessel of less than 12 meters (39.4 ft.) in length shall be equipped with a whistle or horn, or some other sounding device capable of making an efficient sound signal.

Common Sound Signals

Changing Direction

• One short blast tells other boaters:
  • If inland: “I intend to turn to my right.”
  • If international: “I am turning to my right.”
• Two short blasts tells other boaters:
  • If inland: “I intend to turn to my left.”
  • If international: “I am turning to my left.”
• Three short blasts 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 powerboats when underway.
• One prolonged plus two short blasts at intervals of not more than two minutes is the signal used by sailboats under sail alone.

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 are to signal danger or that you do not understand the other boater’s intentions