Ask A Maritime Attorney: What are Coast Guard regulations for commercial vessels over 40 feet long when backing up?


What are the Coast Guard regulations regarding commercial vessels over 40 feet long when they are backing up? The U,S, Coast Guard code I found says there should be horn blasts when reversing. It seems to me that the commercial vessels docked in my harbor are not abiding by any signaling codes. This presents a hazard to other mariners. The public needs to be advised of the danger presented and the lack of code enforcement.


Our reader is complaining that commercial boats are not using the sound signals set forth in the “Rules of the Road.” I will first note that commercial mariners are invariably very familiar with the Rules, and they usually follow those Rules to the letter. But let’s take a look.

Our reader is looking for guidance under the International and Inland Navigation Rules, also known as the “Rules of the Road.” The Navigation Rules were formalized in 1972 in the Convention on the International Regulations for Preventing Collisions at Sea (commonly called COLREGS, but I’ll refer to them simply as the “Rules”). The Rules include guidelines for the operation of a vessel when other vessels are in sight, and for the use of sound signals, lights and day shapes.

We should first note that, contrary to our reader’s assumption, this has nothing to do with the length of the boat or whether it is a pleasure boat or a commercial boat. The rules make no distinction at all between recreational and commercial boats. Rule 1(a) provides simply that “These Rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.” In other words, they apply to everyone. A system that provides different sets of rules for boats operating on the same waterway would be pretty chaotic.

Likewise, the Rules make no distinction for the length of a vessel in the operation of the vessel or the use of sound signals. There are, however, differences in how a vessel must be equipped based on the size of the vessel. For example, Rule 33(b) provides that a “vessel of less than 12 meters in length shall not be obliged to carry [permanently installed sound signaling appliances] but if she does not, she shall be provided with some other means of making an efficient sound signal” (such as a portable air horn).  This exception for the length of the vessel applies to how it is equipped – not to the actual making of the sound signals.

Regarding the actual sound signals, our reader is concerned about the signal required when a vessel is backing up. His question is referring to Rule 34(a)(i) of the Inland Rules, which provides that when “power-driven vessels are in sight of one another . . . when maneuvering as authorized or required by these Rules: (i) shall indicate that maneuver by the following signals on her whistle: one short blast to mean ‘I intend to leave you on my port side,’ two short blasts to mean ‘I intend to leave you on my starboard side,’ and three short blasts to mean ‘I am operating astern propulsion.’ So, he was looking for, but did not hear, three short blasts.

The Navigation Rules comprise an international regulatory strategy that has been codified in the U.S. Code of Federal Regulation. Compliance is not optional, and an operator may be fined for failing to comply with the Rules. However, failure to comply is not, by itself, a crime.  Instead, compliance is guided through civil and administrative action in the event of a collision or other incident.

Our reader is upset at the lack of enforcement in his harbor, but I would first ask whether he complies with all sound signals on his boat. Does he sound three short blasts every time he backs out of his slip? And as noted above there are other signals. For example, does he sound one short blast when he intends to pass an approaching boat on his port side? Maybe. But uniform and unwavering enforcement of the Rules for sound signals is just not practical.  Instead, boaters are generally left to the use of their own discretion.  They are expected to be familiar with all the Rules, including the Rules for sound signals, so that they are prepared to use them properly when a situation arises. Failure to do so may lead to a finding of fault in the event of a lawsuit after a collision, or for a commercial operator, it may lead to the Coast Guard taking action against their license after a collision.

The most important take-away here is to know the Rules and to be prepared to apply them correctly as situations arise with other boats on the water. We should point out that every boat that is 12 meters or more in length is required to carry a copy of the Rules aboard at all times. Pick up a copy and read through them. The Rules are available in a book that is sold at most marine hardware stores, or online at

David Weil is licensed to practice law in the state of California and as such, some of the information provided in this column may not be applicable in a jurisdiction outside of California. Please note also that no two legal situations are alike, and it is impossible to provide accurate legal advice without knowing all the facts of a particular situation. Therefore, the information provided in this column should not be regarded as individual legal advice, and readers should not act upon this information without seeking the opinion of an attorney in their home state.

 David Weil is the managing attorney at Weil & Associates ( in Seal Beach. He is certified as a Specialist in Admiralty and Maritime Law by the State Bar of California Board of Legal Specialization and a “Proctor in Admiralty” Member of the Maritime Law Association of the United States, an adjunct professor of Admiralty Law, and former legal counsel to the California Yacht Brokers Association. If you have a maritime law question for Weil, he can be contacted at 562-799-5508, through his website at,  or via email at


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