Examples of Sound Signals Used for Encountering Situations
Navigation rules include the use of sound signals to communicate with other boaters.
Note that the following illustrations are not drawn to scale. The boats are shown closer to each other than they should be when actually encountering another vessel on the water.

TOOT (one short blast) tells other boaters "I intend to pass you on my port (left) side."

TOOT TOOT (two short blasts) tells other boaters "I intend to pass you on my starboard (right) side."
The other vessel will sound the same signal if in agreement with the proposed maneuver.