Information from the Code of Federal Regulations Title 33 Part 83
Navigation Rules require sound signals to be made under certain circumstances. Meeting, crossing, and overtaking situations, described in the Navigation Rules beginning with Rule 32, are examples of circumstances in which sound signals are required. Recreational vessels are also required to use sound signals during periods of reduced visibility and while at anchor.
The sound producing devices required for vessels is as follows:
|12+ meters (39.4+ ft)||x|
|20+ meters (65.6+ ft)||x||x|
|100+ meters (328.1+ ft)||x||x||x|