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If Another Boat Signals Their Intention to Pass You From Astern What Should You Do

Written by Anthony Roberts / Fact checked by Jonathan Larson

if another boat signals their intention to pass you from astern what should you do

There are many rules in waterway transportation that are similar to regulations for road traffic. One of these rules is applied to boats when they want to surpass each other on a waterway.

This leads us to the question: “If another boat signals their intention to pass you from astern what should you do?” Knowing the answer to this will help you practice commuting safely, especially when passing other crafts during high boating season.

If you are looking for proper instructions on what to do in this particular situation, you are in the right place. In this post, we will provide knowledge about navigating while other vessels are attempting to surpass.

Also, other suggestions and tips will be included throughout the text, so make sure you stay until the end!

What Are Sound Signals and Their Meanings


Sound signals and light signals are the two most simple and important types of signal when boaters want to communicate with each other. In particular, sound signals should only be used when boats are able to observe one another and they plan to meet or pass within half a mile from each other.

These indicators should never be utilized in foggy weather or other low-visibility situations in which the crafts are not observable. In these cases, only mist signals should be used.

“Blasts” refers to sound signals. For warnings and guidance indications, two separate blasts are employed:

  • Short blast: often lasts for 1 second
  • Prolonged blast: often lasts for 4 to 6 seconds

Furthermore, there are a variety of blast combinations for varied water flows that require both short and lengthy blasts. While power-driven boats intend to meet and cross, each craft underway must employ the following signals when moving as allowed or requested by the Inland regulations:

  • 1 prolonged blast: This signal means that you are exiting a dock or your slip.
  • 1 short blast: This signal indicates: “I plan to surpass you on my boat’s port side.”
  • 2 short blasts: This implies: “I aim to pass you on MY vessel’s starboard side.”
  • 3 short blasts: If you’re drifting away from a port, this signifies you’re using astern propulsion.
  • 1 prolonged blast and 3 short blasts: Three quick blasts signify you’re backing up, while a prolonged blast shows you’re getting started. When you’re leaving a dock backwards, this is the sound you’ll hear.
  • 5 short blasts: This signal is a danger warning. You send the DANGER signal when you believe their projected movement is risky to your craft or theirs.

Necessary Sound Signals for Each Type of Boat While Passing


Sounds, similar to lights, play an important part in determining what vessels are doing. Another stage in becoming a “qualified mariner” is to comprehend sounds that you hear. Almost every vessel is obliged to install some sort of sound generator. You have a lot of freedom in terms of what kind of sound gadget you select, but the louder it is, the better effect it will provide!

  • For boats that are shorter than 39.4 ft in length

These boats require a gadget that can provide high-quality sound. A bell, air raid siren, whistle or air horn is usually used. They’re the right tools, even if the idea of making music with pans and pots is appealing.

  • For boats that are longer than 39.4 ft but below 65.5 ft

These ships require a whistle as well as a bell. Sounds from the whistle need to be heard for about a half-mile. Boaters should purchase a bell that features a minimum 7.87-inches diameter.

Different Maneuvering Signals When Crossing

Aside from their sizes or responses from other boats, maneuvering signals are also varied depending on the case which boaters are encountering. Here are some examples and descriptions about how sound signals are used in different boating situations. You should remember these instructions to apply them in each suitable scenario!

1. Passing ahead

A quick blast should indicate the purpose of one of the boats when they are close to approaching each other. The opposite vessel must respond quickly. Both of the craft will have to steer to their starboard side to move through the dock on either side.

2. Overtaking a side

When two boats are traveling in the same direction, the vessel that plans to cross astern upon the other’s starboard side needs to give a brief blast. If there’s a safe path, the other watercraft should also reply like the previous one.

Two brief blasts are the correct signals if the objective is to overtake on the dock side. If there’s no danger, the other vessel should react similarly. Remember to respond by five short blasts if it is dangerous to practice the action.

3. Crossing on starboard side

When you encounter the other vessel on your starboard side, you must not cross in front of it. Instead, you are suggested to act as a give-way boat and clear a path for the other boat while maintaining your path and speed.

When it appears that the latter vessel is not responding, the stand-by boat shouldn’t spend too much time navigating around.

For more details, please check out this video at the link: Rule 35: Sound Signals In Restricted Visibility | Sound Signals In Depth


Understanding what to do if another boat signals their intention to pass you from astern what should you do is actually very important as it might help you deal with surprising situations. Also, you must be aware of the indications given by the vessels you encounter and be accountable for your responses. Hence, collisions and bad incidents will be avoided.

We hope that the above information is useful during your hunting experience. Did you enjoy the article? Do you want to add anything else? Please let us know and leave a comment below.

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