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United States Coast Guard
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AIS Requirements

Title 33, Code of Federal Regulations

§ 164.01 Applicability

(a) This part (except as specifically limited by this section) applies to each self-propelled vessel of 1600 or more gross tons (except as provided in paragraphs (c) and (d) of this section, or for foreign vessels described in §164.02) when it is operating in the navigable waters of the United States except the St. Lawrence Seaway.

(b) * * *

(c) Provisions of §§ 164.11(a)(2) and (c), 164.30, 164.33, and 164.46 do not apply to warships or other vessels owned, leased, or operated by the United States Government and used only in government non-commercial service when these vessels are equipped with electronic navigation systems that have met the applicable agency regulations regarding navigation safety.

(d) Provisions of § 164.46 apply to some self-propelled vessels of less than 1600 gross tonnage.

§ 164.02 Applicability exception for foreign vessels.

(a) Except for § 164.46(c), none of the requirements of this part apply to foreign vessels that:

     (1) Are not destined for, or departing from, a port or place subject to the jurisdiction of the United States; and

     (2) Are in:
         (i) Innocent passage through the territorial sea of the United States; or
         (ii) Transit through navigable waters of the United States which form a part of an international strait.

§ 164.46 Automatic Identification System

(a) Definitions.  As used in this section-–
Automatic Identification Systems or AIS means a maritime navigation safety communications system standardized by the International Telecommunication Union (ITU), adopted by the International Maritime Organization (IMO), that--

     (1) 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;

     (2) Receives automatically such information from similarly fitted ships, monitors and tracks ships; and

     (3) Exchanges data with shore-based facilities.

Gross tonnage means tonnage as defined under the International Convention on Tonnage Measurement of Ships, 1969.

International voyage means a voyage from a country to which the present International Convention for the Safety of Life at Sea applies to a port outside such country, or conversely.

Properly installed, operational means an Automatic Identification System (AIS) that is installed and operated using the guidelines set forth by the International Maritime Organization (IMO) Resolution A.917(22) and Safety of Navigation Circulars (SN/Circ.) 227, 244, 245, and SN.1/Circ.289; or National Marine Electronics Association (NMEA) Installation Standard 0400-3.10 in lieu of SN/Circ.227 and 245 (incorporated by reference, see § 164.03).

 (b) AIS carriage -

      (1) AIS Class A device. The following vessels must have on board a properly installed, operational USCG Type-approved* AIS Class A device:

          (i) A self-propelled vessel of 65 feet or more in length**, engaged in commercial service.
          (ii) A towing vessel of 26 feet or more in length** and more than 600 horsepower, engaged in commercial service.
          (iii) A self-propelled vessel that is certificated to carry more than 150 passengers.
          (iv) A self-propelled vessel engaged in dredging operations in or near a commercial channel or shipping fairway in a manner likely to restrict or affect navigation of other vessels.
          (v) A self-propelled vessel engaged in the movement of –

               (A) Certain dangerous cargo as defined in subpart C of part 160 of this chapter, or

               (B) Flammable or combustible liquid cargo in bulk that is listed in 46 CFR 30.25–1, Table 30.25–1.

      (2) AIS Class B device. AIS Class B device in lieu of an AIS Class A device is permissible on the following vessels if they are not subject to pilotage by other than the vessel Master or crew:

          (i) fishing industry vessels;
          (ii) Vessels identified in paragraph (b)(1)(i) of this section that is certificated to carry less than 150 passengers and that–

               (A) Do not operate in a Vessel Traffic Service (VTS) or Vessel Movement Reporting System (VMRS) area defined in Table 161.12(c) of § 161.12 of this chapter, and

               (B) Do not operate at speeds in excess of 14 knots; and

          (iii) Vessels identified in paragraph (b)(1)(iv) of this section engaged in dredging operations.

Note to paragraph (b): Under 33 U.S.C. 1223(b)(3) and 33 CFR 160.111, a Coast Guard Captain of the Port (COTP) may restrict the operation of a vessel if he or she determines that by reason of weather, visibility, sea conditions, port congestion, other hazardous circumstances, or the condition of such vessel, the restriction is justified in the interest of safety. In certain circumstances, if a COTP is concerned that the operation of a vessel not subject to § 164.46 would be unsafe, the COTP may determine that voluntary installation of AIS by the operator would mitigate that concern.

(c) SOLAS provisions. The following self-propelled vessels must comply with International Convention for Safety of Life at Sea (SOLAS), as amended, Chapter V, regulation (Positioning System), 19.2.4 (AIS Class A), and (Transmitting Heading Device) or (Gyro Compass) as applicable (Incorporated by reference, see § 164.03):

     (1) A vessel of 300 gross tonnage or more, on an international voyage.

     (2) A vessel of 150 gross tonnage or more, when carrying more than 12 passengers on an international voyage.

(d) Operations. The requirements in this paragraph are applicable to any vessel equipped with AIS.

     (1) Use of AIS does not relieve the vessel of the requirements to sound whistle signals or display lights or shapes in accordance with the International Regulations for Preventing Collisions at Sea, 1972 (72 COLREGS), 28 U.S.T. 3459, T.I.A.S. 8587, or Inland Navigation Rules, 33 CFR part 83; nor of the radio requirements of the Vessel Bridge-to-Bridge Radiotelephone Act, 33 U.S.C. 1201-1208, part 26 of this chapter, and 47 CFR part 80.

     (2) AIS must be maintained in effective operating condition, which includes--

         (i) The ability to reinitialize the AIS, which requires access to and knowledge of the AIS power source and password;
         (ii) The ability to access AIS information from the primary conning position of the vessel;
         (iii) The accurate broadcast of a properly assigned Maritime Mobile Service Identity (MMSI) number;
         (iv) The accurate input and upkeep of all AIS data fields and system updates; and
         (v) For those vessels denoted in paragraph (b) of this section, the continual operation of AIS and its associated devices (e.g., positioning system, gyro, converters, displays) at all times while the vessel is underway or at anchor, and, if moored, at least 15 minutes prior to getting underway; except when its operation would compromise the safety or security of the vessel or a security incident is imminent. The AIS should be returned to continuous operation as soon as the compromise has been mitigated or the security incident has passed. The time and reason for the silent period should be recorded in the ship's official log and reported to the nearest Captain of the Port or Vessel Traffic Center (VTC).

    (3) AIS safety-related text messaging must be conducted in English and solely to exchange or communicate pertinent navigation safety information (analogous to a SECURITE broadcast). Although not prohibited, AIS text messaging should not be relied upon as the primary means for broadcasting distress (MAYDAY) or urgent (PAN PAN) communications. (47 CFR 80.1109, Distress, urgency, and safety communications).

    (4) AIS application-specific messaging (ASMs) is permissible, but is limited to applications adopted by the International Maritime Organization (such as IMO SN.1/Circ.289) or those denoted in the International Association of Marine Aids to Navigation and Lighthouse Authorities’ (IALA) ASM Collection for use in the United States or Canada, and to no more than one ASM per minute.

Note to paragraph (d):  The Coast Guard has developed the “U.S. AIS Encoding Guide” to help ensure consistent and accurate data encoding (input) by AIS users.  This Guide is available at our “AIS Frequently Asked Questions” (FAQ #2) World Wide Web page at  Although of great benefit, the interfacing or installation of other external devices or displays (e.g., transmitting heading device, gyro, rate of turn indicator, electronic charting systems, and radar), is not currently required except as denoted in § 164.46(c).  Most application-specific messages require interfacing to an external system that is capable of their portrayal, such as equipment certified to meet Radio Technical Commission for Maritime Services (RTCM) electronic chart system (ECS) standard 10900 series.

(e)  Watchkeeping.  AIS is primarily intended for use by the Master or person in charge of the vessel, or by the person designated by the Master or person in charge to pilot or direct the movement of the vessel, who must maintain a periodic watch for AIS information.

(f)  Portable AIS.  The use of a portable AIS is permissible only to the extent that electromagnetic interference does not affect the proper function of existing navigation and communication equipment on board and such that only one AIS device may be transmitting on board a vessel at any one time.

(g)  AIS Pilot Plug.  The AIS Pilot Plug on any vessel subject to pilotage by other than the vessel Master or crew must be readily available and easily accessible from the primary conning position of the vessel and permanently affixed (not an extension cord) and adjacent (within 3 feet) to a 120-volt 50/60 Hz AC power receptacle (NEMA 5-15).

(h)  Exceptions.  The following vessels may seek up to a 5-year deviation from the AIS requirements of this section by requesting a deviation under § 164.55.             

     (1) Vessels that operate solely within a very confined area (e.g., less than a 1 nautical-mile radius, shipyard, or barge fleeting facility);

     (2) Vessels that conduct only short voyages (less than 1 nautical mile) on a fixed schedule (e.g., a bank-to-bank river ferry service or a tender vessel);

     (3) Vessels that are not likely to encounter other AIS-equipped vessels;

     (4) Vessels whose design or construction makes it impracticable to operate an AIS device (e.g., those that lack electrical power, have an exposed or open cabin, or are submersible); or

     (5) Vessels denoted in paragraph (b)(2) that seek a deviation from requirements in paragraphs (d)(2)(ii) and (e) of this section because their AIS Class B device lacks a display.
         (i)  Prohibition Except for maritime support stations (see 47 CFR 80.5) licensed by the Federal Communications Commission (FCC), broadcasts from AIS Class A or B devices on aircraft, non-self propelled vessels or from land are prohibited.
         (j)  Implementation date.  Those vessels identified in paragraphs (b) and (c) of this section that were not previously subject to AIS carriage must install AIS no later than March 1st, 2016 [eff. 81 FR 20250, 4/7/16]. 

§ 164.53 Deviations from rules and reporting: Non-operating equipment.

(a) If during a voyage any equipment required by this part stops operating properly, the person directing the movement of the vessel may continue to the next port of call, subject to the directions of the District Commander or the Captain of the Port, as provided by part 160 of this chapter.

(b) If the vessel's automatic identification system (AIS), radar, radio navigation receivers, gyrocompass, echo depth sounding device, or primary steering gear stops operating properly, the person directing the movement of the vessel must report or cause to be reported that it is not operating properly to the nearest Captain of the Port, District Commander, or if participating in a Vessel Traffic Service.

[Source: 80 FR 5281; 80 FR 2050]

*   *   *

* USCG type-approved AIS devices are labeled as such on the back of the unit and with the number 165.155/x/y (Class A) or 165.156/x/y (Class B). For a listing of USCG type-approved AIS see the Coast Guard Maritime Information Exchange (CGMIX) EQList. Search: Approval Series Name—Shipborne AIS.

** Length means “overall in length” as defined in 46 USC 2101(28), which means— 
(A) for a foreign vessel or a vessel engaged on a foreign voyage, the greater of— 
    (i) 96 percent of the length on a waterline at 85 percent of the least molded depth measured from the top of the keel (or on a vessel designed with a rake of keel, on a waterline parallel to the designed waterline); or
    (ii) the length from the fore side of the stem to the axis of the rudder stock on that waterline; and  
(B) for any other vessel, the horizontal distance of the hull between the foremost part of the stem and the aftermost part of the stern, excluding fittings and attachments.

Printer-friendly PDF formats of these 2015 requirements, our 2008 proposed requirements, an amalgamation of both, our 2003 requirements, a chart-comparison of all three, and the AIS requirements of Regulation V/19.2.4 of the Safety of Life at Sea Convention and Sec. 102 of the Maritime Transportation Security Act of 2002 (46 U.S.C. 70114).