The United States Coast Guard publishes a "Notice to Mariners" document at the beginning of each year that contains general information on a very comprehensive list of subjects of interest to mariners. This year there was information included in the Notice to Mariners 1/18 in a section under the heading "Automatic Identification System" and marked with an asterisk that denotes "significant change." Because the section on AIS contains significant changes, I am reproducing that section below:
- (64) AUTOMATIC IDENTIFICATION SYSTEM.
Automatic Identification System (AIS) is a maritime navigation safety communications system standardized by the International Telecommunication Union (ITU), adopted by the International Maritime Organization (IMO), that: provides vessel information, including the vessel's identity, type, position, course, speed, navigational status and other safety-related information automatically to appropriately equipped shore stations, other ships, and aircraft; receives automatically such information from similarly fitted ships; monitors and tracks ships; and exchanges data with shore-based facilities. In the United States, AIS carriage extends beyond the IMO requirements and to every commercial self-propelled: (1) Vessel of 65 ft or more in length (regardless of service type); (2) Towing vessel of 26 ft or more in length and more than 600 hp; (3) Vessel certificated to carry more than 150 passengers; (4) Vessel engaged in dredging ops likely to affect or restrict commercial navigation; and, (5) Vessel engaged in the movement of certain dangerous cargo, flammable or combustible liquids carried in bulk.
Notice. The Coast Guard continues to see an unacceptable number of AIS vessels reporting improper ‘Navigational Status’ when at anchor or moored; doing so reduces their reporting rate to once every 3 minutes vice every few seconds, which mitigates network congestion and improves everyone's AIS range. Further, many vessels are broadcasting inaccurate AIS information, stemming from improper operation or encoding of their AIS; particularly regarding their Maritime Mobile Service Identifies (MMSI), IMO number, call-sign, name, dimensions, destination and ETA, etc. To assist AIS users in performing this task correctly, the Coast Guard has developed an Encoding Guide which provides details and examples on how to properly encode each AIS data parameter. This Guide is available on the U.S. Coast Guard Navigation Center website at: https://www.navcen.uscg.gov/AIS. Note, this Guide has been revised, such that, it will require certain users, i.e. tugs and push-boats, to correct certain data parameters, i.e. vessel type and dimensions. Improper use of AIS may subject a vessel to civil penalties.
Warning. AIS is another available means to determine risk of collision. However, assumptions should not be made on the basis of AIS information alone, which unfortunately is fraught with inaccurate or out-dated information. Further, as with any source of navigation information it should not be solely relied upon in making navigational and collision-avoidance decisions (also see Navigation Rule 7). While AIS allows for safety related ship-to-ship text messaging to communicate with others, such as passing arrangements, these communications do NOT relieve users from the requirements set forth in the Vessel Bridge-to-Bridge Radiotelephone regulations (33 CFR §26) or relieve a vessel from the sound or display signals requirements of the Navigation Rules.
Report: To report a problem or for further information regarding AIS, including plans to extend U.S. carriage requirements to most commercial ships transiting U.S. navigable waters, visit: https://www.navcen.uscg.gov/?pageName=AIS or email:
(Supersedes NTM 1(64)17) (USCG)
When a federal agency tasked with enforcement of regulations publishes a public notice followed by a public warning, anyone affected by the notice will be wise to take heed. In some follow-on email correspondence with the USCG on this topic, I was informed:
- "...various AIS users...[have] recently received a letter from their respective USCG Officer-in-Charge, Marine Inspection (OCMI) informing them of discrepancies noted in their AIS static data transmission; directing them to correct said discrepancies; and, that not doing so may subject them to civil penalty action."
I suspect that the USCG is probably mostly looking at commercial ships whose carriage of AIS is mandatory, but there isn't anything in the announcement that suggests recreational boaters with AIS transponders will get a free pass. It seems prudent to review the static data in any AIS transponder, Class-A or Class-B, and verify it is correct.
To assist mariners in complying with AIS data mandates, the USCG has, for some time now, made available a VESSEL INFORMATION VERIFICATION SERVICE (VIVS). This service collects AIS data from vessels and then parses or analyzing the data to see if the data conforms with regulations. You can search for a vessel by name, MMSI, callsign, or other parameters. If the vessel appears in the database of collected AIS data received by the USCG, you can view an analysis of the data to see if the USCG noted any discrepancies in the data.
I took VIVS for a test drive a few minutes ago. I picked a commercial ship at random from a display of AIS targets in my local waters, then entered the MMSI of the vessel into the search. I was very surprised that the search produced no results. Upon further testing, I discovered that the field for MMSI is very intolerant of any leading or trailing spaces on the number entered. I had cut-and-pasted a number and inadvertently included a trailing space. That prevented the search from finding any data. Submitting the search with just the nine-digit MMSI and no leading or trailing spaces produced the expected result. Curiously, the vessel I selected at random had an error it its static AIS data: it was broadcasting its draft as 0-meters.