Whistle Signals

Anyone that knows me knows that I am not in favor of "over regulation." However, I am a strong proponent of the Navigation Rules. But the observance of the Rules can change over time. One thing that has changed noticeably in the past twenty years or so is the practice of using maneuvering and warning signals in inland waters.

Sound signals are prescribed under both Inland and International Nav Rules. Our focus today will be signals under the U.S. Inland Rules. Before discussing the sound signals, it is important to note that under the Inland Rules, a conversation on your marine VHF radio can substitute for maneuvering signals.

The increasing use of the marine VHF radio in the last few decades has reduced the average mariner's reliance on maneuvering signals. Given that some mariners are not within earshot of their radios makes it difficult to negotiate a "close quarters" maneuver with them.

In cases where a mariner's VHF radio is not turned on or is not audible, communication with that mariner is limited to a few options. Note that throwing a rock at him to get his attention would not be an exercise in good seamanship. We are left with the "whistle signals" prescribed in the Nav Rules.

The Rules refer to a "whistle" as a device used to make a sound signal. Your vessel may have an electric device that is labeled "horn." It amounts to the same thing as long as the sound produced equates to the sound produced by a comparable "air" or "steam" operated whistle. The sound of the whistle/horn varies with the size of the vessel.

Just as Morse code uses one or more dots and dashes to represent a letter, the maneuvering Rules use one or more blasts of the whistle to state your intention. Blasts on the whistle can be "short" (1 second) or "prolonged" (4-6 seconds). One or more blasts make up a maneuvering signal.

Let’s put the above information into a practical scenario. If you are in the Intracoastal Waterway and seek to pass a vessel that is ahead of you in the channel, you might hail that vessel on VHF channel 16. After switching to a "working channel," you can discuss the maneuver, provided that the other vessel operator is listening to the radio. If not, your whistle will get their attention.

There are two Inland Rules maneuvering signals that come into play when passing (overtaking) another vessel. Two "short" blasts communicates to the vessel ahead that you intend to pass them on their port side. One "short" blast communicates that you intend to pass on their starboard side. Did you notice that I said you "intend" to pass? That's because the maneuver is not authorized unless the other vessel operator agrees that it is safe to execute.

For the other vessel operator to reply in the affirmative, they return the same whistle signal. To reply in disagreement, they signal with five or more short and rapid blasts on the whistle. Vessels within a 1/2 mile of each other are required to either signal or use VHF radio communication.

While the above signals are still on the books, they are practiced infrequently. If you use them you might just start a trend!

Until next time, I wish you clear skies, fair winds, and calm seas!