The Automatic Identification System (AIS) is a critical navigational tool that enhances maritime safety by enabling real-time tracking of vessel positions and movements. In the United States, the U.S. Coast Guard (USCG) has established detailed regulations governing the installation, operation, and maintenance of AIS on commercial and large vessels. These requirements are outlined in Title 33 of the Code of Federal Regulations (CFR), particularly in § 164.46 and related sections. This article provides a technical overview of these regulations, focusing on installation procedures, compliance mandates, and operational best practices for AIS as defined by the USCG.
AIS Overview and Regulatory Context
Automatic Identification Systems (AIS) are digital communication systems that transmit vessel data such as position, speed, and course using VHF radio frequencies. The USCG mandates AIS installation for specific vessel types and sizes to ensure consistent and accurate vessel tracking, particularly in high-traffic and international waters.
The core regulation governing AIS in the U.S. is found in 33 CFR § 164.46, which outlines carriage requirements, installation standards, and operational procedures. These regulations are aligned with international standards set by the International Maritime Organization (IMO) and the Safety of Life at Sea (SOLAS) Convention. Vessels subject to these rules must ensure that their AIS systems are installed and maintained according to the technical specifications and guidance provided in official documentation.
Vessel Requirements for AIS Carriage
According to the USCG, AIS installation is mandatory for the following vessel types:
- Self-propelled vessels of 65 feet or more in length, engaged in commercial service.
- Towing vessels of 26 feet or more in length and more than 600 horsepower, engaged in commercial service.
- Vessels of 300 gross tonnage or more on an international voyage.
- Vessels of 150 gross tonnage or more carrying more than 12 passengers on an international voyage.
These requirements are based on the vessel's size, commercial use, and international voyage status. The goal is to ensure that all vessels operating in U.S. waters or engaging in international travel are equipped with a reliable means of identifying and tracking each other.
Vessels not previously subject to AIS carriage must comply by March 1st, 2016, as outlined in § 164.53. Any deviation from these requirements must be formally requested and approved by the Coast Guard under § 164.55, which allows for exceptions in certain cases for a period of up to five years.
Installation and Technical Standards
Installation of an AIS system must adhere to specific technical and operational standards to ensure system reliability and compliance with USCG regulations. The following key requirements apply:
1. Proper Installation and Certification
AIS must be properly installed and operational according to the technical guidelines established by the following entities:
- International Maritime Organization (IMO):
- Resolution A.917(22)
- Safety of Navigation Circulars (SN/Circ.) 227, 244, 245, and SN.1/Circ.289
- National Marine Electronics Association (NMEA) Installation Standard 0400-3.10, which is accepted as an alternative to SN/Circ.227 and 245.
These standards ensure that the AIS is integrated correctly with the vessel’s navigation and communication systems. Proper installation includes interfacing with devices such as the gyrocompass, rate of turn indicator, electronic charting system (ECS), and radar, where applicable.
2. Access and Control from the Primary Conning Position
The AIS must be readily accessible from the primary conning position of the vessel. This ensures that the master or designated operator can monitor and control the system during navigation. The system must also be permanently affixed, and if a portable system is used, it must not interfere with the operation of other onboard equipment.
3. AIS Pilot Plug
For vessels subject to pilotage, the AIS Pilot Plug must be available and accessible from the primary conning position. It must be permanently affixed and within 3 feet of a 120-volt 50/60 Hz AC power receptacle (NEMA 5-15). This ensures that the pilot can quickly and safely connect to the vessel's navigation systems without the need for extension cords or additional wiring.
4. Power and Reinitialization
The AIS must be connected to a reliable power source, and the password for reinitialization must be accessible to the designated operator. The system should be capable of reinitialization in the event of a failure or power outage. This includes the ability to restart the system and retransmit the vessel’s current data without delay.
5. MMSI Number and Data Accuracy
An accurately assigned Maritime Mobile Service Identity (MMSI) number must be broadcast by the AIS. This 9-digit number is essential for identifying the vessel and must be programmed correctly. Additionally, all data fields must be regularly updated and maintained to ensure the transmission of accurate and current vessel information.
Operational Requirements and Compliance
Once installed, the AIS must be maintained in effective operating condition at all times. This includes the following key operational requirements:
1. Continuous Operation
For vessels subject to the carriage requirements, the AIS must be continuously operational while the vessel is:
- Underway
- At anchor
- Moored (at least 15 minutes before getting underway)
However, the system may be temporarily turned off in cases where its operation would compromise the safety or security of the vessel, or if a security incident is imminent. In such cases, the vessel must return to continuous operation as soon as the risk has passed.
2. Silent Periods and Logging
Any silent period (when the AIS is not operational) must be recorded in the ship’s official log and reported to the nearest Captain of the Port (COTP) or Vessel Traffic Center (VTC). The log must include the time and reason for the interruption to ensure transparency and accountability.
3. Watchkeeping
The Master or person in charge of the vessel is responsible for maintaining a periodic watch for AIS information. This includes monitoring received data from other vessels to avoid collisions and ensure safe navigation. The designated operator must be trained in the use and interpretation of AIS data.
4. Use in VTS and VMRS Areas
Vessels subject to AIS carriage must comply with Vessel Traffic Service (VTS) or Vessel Movement Reporting System (VMRS) requirements in designated areas. These systems rely on continuous AIS data to monitor vessel traffic and ensure safe passage through busy or restricted waterways.
For vessels not subject to AIS carriage, the Coast Guard Captain of the Port (COTP) may still require voluntary installation of AIS in certain hazardous or high-risk conditions, such as poor visibility, adverse weather, or heavy traffic. This is done to enhance situational awareness and mitigate potential risks.
Prohibited Uses and Restrictions
The USCG has set clear restrictions on the use of AIS to prevent interference with maritime communication and navigation systems:
1. Prohibited Broadcasts
- AIS Class A or B devices may not be used from aircraft, non-self-propelled vessels, or land-based locations, unless the device is part of a licensed maritime support station.
- Multiple AIS devices may not transmit simultaneously on a single vessel, as this can cause signal interference and compromise the integrity of the system.
2. Speed and Area Restrictions
Vessels not subject to AIS carriage may be restricted from operating in VTS or VMRS areas if the COTP determines that their presence poses a safety risk. These restrictions are based on factors such as:
- Weather conditions
- Visibility
- Port congestion
- Sea conditions
- Vessel condition or design
In such cases, the COTP may require the vessel to install AIS voluntarily to improve situational awareness and reduce the risk of collision or accident.
Best Practices and Compliance Tools
To ensure compliance with AIS regulations, vessel operators should follow these best practices:
1. Use of the U.S. AIS Encoding Guide
The USCG has developed the U.S. AIS Encoding Guide to help vessel operators ensure consistent and accurate data input into the AIS system. This guide is available on the official AIS Frequently Asked Questions (FAQ #2) webpage at www.navcen.uscg.gov/ais-frequently-asked-question#2. While not mandatory, the guide is a valuable resource for ensuring that data fields such as position, speed, and course are correctly formatted and transmitted.
2. Integration with External Navigation Systems
AIS should be integrated with external navigation systems such as gyrocompasses, radar, and electronic charting systems (ECS) to ensure that the vessel can accurately interpret and respond to incoming data. This is especially important for vessels operating in complex or high-traffic environments.
3. Regular Maintenance and Updates
All AIS systems must be regularly maintained and updated to ensure continued reliability. This includes:
- Periodic testing of system functionality
- Software updates to maintain compatibility with regulatory changes
- Calibration of external sensors such as gyro and GPS
Operators should also ensure that system passwords and reinitialization procedures are known and accessible to authorized personnel.
Conclusion
The installation and operation of AIS on U.S. commercial and large vessels are governed by a comprehensive set of regulations designed to enhance maritime safety and situational awareness. These requirements include mandatory installation for specific vessel types, adherence to technical standards, and continuous operation while underway. Vessels must also maintain accurate data fields, ensure system accessibility, and comply with watchkeeping and logging requirements.
Compliance with these regulations is essential not only for legal adherence but also for the safety of the vessel, its crew, and surrounding maritime traffic. Vessel operators are encouraged to familiarize themselves with the technical specifications and guidance provided by the USCG and to maintain their AIS systems according to the highest standards of reliability and accuracy.