LEGAL REQUIREMENT

By virtue of Regulation 19 of Chapter V of the International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended, all ships of 300 gross tonnage or more and engaged on international voyages must be fitted with Class A AIS equipment. In law, all yachts are ships – and it is irrelevant whether registered as a private or commercial vessel. Class B devices may be carried on yachts which are not subject to the SOLAS requirements. Certain national laws take this further. For example, US Federal law requires commercial vessels of just 65 feet and over to be fitted with a Class A AIS device.

HOW IT WORKS

The system is contained within a small box, containing one very high frequency (VHF) radio transmitter, various VHF receivers and a central processing unit. To this is attached antennae, and interfaces for heading, speed devices and other shipborne sensors, plus interfaces to radar, Automatic Radar Plotting Aids (ARPA), Electronic Chart System/Electronic Chart Display and Information System (ECS/ECDIS) and Integrated Navigation Systems (INS). There’s also a display and keyboard to input and retrieve data.

The AIS can be connected either to an additional dedicated AIS display unit, possibly one with a large graphic display, or as an input to existing navigational system devices such as a radar display, ECS, ECDIS, or INS.

INFORMATION SHARED

The AIS information is transmitted continuously by a ship, and includes the following three types:

• Static information, which is entered into the AIS on installation and need only be changed if the ship changes its name, Maritime Mobile Service Identity (MMSI), location of the electronic position fixing system (EPFS) antenna, or undergoes a major conversion from one ship type to another;

• Dynamic information, which, apart from navigational status information, is automatically updated from the ship sensors connected to AIS; and

• Voyage-related information, some of which such as destination and estimated time of arrival (ETA) will need to be entered manually at the start of the voyage and kept up to date as necessary.

INCOMPLETE PICTURE

AIS doesn’t always give the complete picture, and – as with any navigational aid – should only be used by itself – especially for collision-avoidance. It doesn’t take the place of radar target-tracking. The officer of the watch (OOW) should always be aware that other ships, in particular smaller leisure craft, fishing boats and warships might not be fitted with AIS. The OOW should always be aware that AIS fitted on other ships as a mandatory carriage requirement might, under certain circumstances, be switched off on the master's professional judgement.

SWITCHING OFF

Details of yachts whose AIS is switched on maybe accessed by anyone, anywhere, simply by looking at MarineTraffic, VesselFinder or any of the other myriad of similar websites. Not all owners will be happy about this.

According to the International Maritime Organisation’s Resolution A.1106(29) of 14 December 2015, entitled Revised Guidelines for The Onboard Operational Use of Shipborne Automatic Identification Systems (AIS):

AIS should always be in operation when ships are underway or at anchor. If the master believes that the continual operation of AIS might compromise the safety or security of his/her ship or where security incidents are imminent, the AIS may be switched off. Unless it would further compromise the safety or security, if the ship is operating in a mandatory ship reporting system, the master should report this action and the reason for doing so to the competent authority. Actions of this nature should always be recorded in the ship's logbook together with the reason for doing so. The master should however restart the AIS as soon as the source of danger has disappeared. If the AIS is shut down, static data and voyage-related information remains stored. Restart is done by switching on the power to the AIS unit. Ship's own data will be transmitted after a two-minute initialization period. In ports AIS operation should be in accordance with port requirements.

CONSEQUENCES

Port state authorities will expect AIS to be operational, and may impose penalties for this not being the case – especially where there is a collision which AIS may have helped to avoid. Keep in mind, too, that non-compliance with more stringent local regulations will be punished.

Even in international waters, where a yacht goes dark other than allowed by Resolution A.1106(29), while this may not be noticed by the flag state authority, if there’s a collision then insurance underwriters could claim that, without this important navigational aid working, the vessel was, in law, unseaworthy, and they are entitled to refuse payment.

But going dark may not be intentional. Interference, weak radio signals and patchy satellite reception can all compromise AIS data exchange. Distinguishing intentional from unintentional signal drop-outs is difficult but not impossible. The frequency and regularity of drop-outs prior to a full blackout may be indicative.

And the reason may not be malevolent. It is known, for example, that in certain parts of the world fishing vessels switch off AIS in order not to reveal productive catch areas to competitors.

CONCLUSION

Whether we, as owners, like it or not, AIS is governed by international convention – and it’s here to stay. If there are legitimate concerns then going dark may be permissible, but it’s as well to discuss this with the captain and insurance underwriter well in advance of a transit through waters in which it may be prudent or desirable.