When Can You Switch Off AIS?

AIS is the Automatic Identification System that is compulsory on most vessels. Despite its compulsory status, there are a few very select occasions when a master is permitted to deactivate a ship’s AIS.

A master may switch off a ship’s AIS if they believe that its operation could compromise the safety or security of the vessel. Examples include transiting high-risk piracy areas where the location of the vessel needs to be kept confidential.

Although there are a few legitimate reasons for switching the AIS off, there are plenty of illegal reasons that a ship’s crew might deactivate it as well.

Legitimate reasons to switch off AIS

There are only a couple of legitimate reasons to turn off your AIS. Your AIS is there to improve your safety and the safety of other vessels in your vicinity. When you deactivate your AIS, you need to be aware that you are reducing overall safety.

When you switch off your AIS, it means you cannot be seen as easily. It is harder for other people to track your position. The only legitimate reasons for switching it off revolve around the fact that it will be safer if your location remains unknown.

Switching off AIS for security concerns

The most common reason to switch off your AIS is for security concerns. For example, if you are transiting through a region that is known for pirate attacks.

With AIS switched on, anyone can see your current location, course and speed. It is very easy for someone to plan to intercept a ship by extrapolating their likely location in a few hours. In an area where pirates are known to operate, you don’t want to give them that advantage.

Instead, if the first indication of a ship is visual, there is a far smaller window for pirates to plan and get on board.

The International Maritime Organisation (IMO) gives the master of every ship the authority to switch off their AIS in this sort of situation:

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.

IMO Resolution A.1106(29)

As with most safety and security concerns, the master of a ship has the authority to act to preserve the safety of life and property.

An interesting variation to this is in the Gulf of Aden. Ordinarily, the master would choose to deactivate AIS to make the ship harder to track. In the Gulf of Aden, however, the large presence of military vessels means that ships are often advised to keep their AIS running, and just minimise the data to some vital statistics.

The naval forces in the Gulf of Aden prefer to be able to monitor vessels so that they can assist when required.

Irrespective of naval advice, the master does always maintain the overriding responsibility for the vessel so can turn off the AIS if it is determined necessary for safety and security.

Switching off AIS for law enforcement purposes

AIS can usually be deactivated by law enforcement vessels if it is for law enforcement. This can include both civilian and military vessels.

If we take the example of the Gulf of Aden again, the military ships operating will want their location to remain unknown. They are much more effective as a deterrent if you don’t know where they are. If their AIS was running, it would be too easy for pirate vessels to disguise as fishing boats when they know a law enforcement vessel is close by.

There have even been reports of the attempted hijacking of military vessels that have been mistaken for cargo ships. Looking at the skiffs involved, it is unlikely that those on board would have used AIS, but you can still see the advantages for military ships switching it off.

Aside from piracy, other law enforcement also benefits from running without AIS. Situations like smuggling and fishery protection are classic examples.

In both cases, the effectiveness of the operation is increased when the location of the enforcing vessel remains unknown. Not only is the chance of catching criminal activity increased, but the added element of surprise acts as a better deterrent.

Illegal reasons to switch off AIS

We’ve covered legitimate reasons for switching off your AIS, but there are a whole host of illegal reasons that cause people to switch off their AIS as well. AIS is just a piece of electronic equipment carried on board. Anyone can secretly turn it off, or just avoid fitting it in the first place.

I am not advocating switching off your AIS, but it is important to know that there are a lot of situations where people do turn it off. It is particularly important as more people seem to be incorrectly using it for collision avoidance without realising how easy it is for boats and ships to go undetected.

Switching off AIS for fishing activity

Forbes has recently published (New Oceana Report Suggests Shady Fishing Practices By Large Fleet Near Galápagos) where they discuss illegal fishing activity around the Galapagos Islands.

It discusses the practise of fishing vessels “going dark” by switching off their AIS for an extended period. It looks particularly suspicious when a vessel near a controlled area disappears. Usually, they disappear for a time and then reappear again later on. The vessel in question could have easily covered the distance between the two locations in a far shorter time, suggesting they spent time conducting an illegal activity en route.

When the AIS of fishing vessels disappears, it always raises suspicions. AIS is there to improve the safety of vessels by increasing their visibility and reducing the chance of collisions. A fishing vessel disappearing is an action that reduces safety, so you are only left with two scenarios. Either the AIS has malfunctioned, or the vessel does not want to be monitored. In both situations, it will draw the attention of coastal authorities.

The prospect of illegal fishing grabs the attention of fishery patrol vessels as they want to stop that activity. The transmission disappearing also draws attention though as concerns are then raised for the safety of those on board. 

Switching off AIS for smuggling

It is more unusual for vessels to turn off their AIS for smuggling, but it does happen. Usually, it is smuggling vessels operating on a particular route that will turn off their AIS. Others, where they are smuggling small quantities within legitimate cargos, will always keep their AIS running as they want to arouse less suspicion.

The thing with smuggling is that you commonly find two sorts. Either it is a smaller boat carrying an entire cargo of smuggled goods, or it is a larger ship where goods are hidden within the legitimate cargo.

When smaller boats are smuggling, they are usually below the requirements for AIS anyway, so they would usually just avoid fitting it in the first place. If it has never been fitted, it isn’t suspicious when it isn’t running.

On larger vessels, smugglers try to keep up the appearance of conducting legitimate activities anyway. They would keep their AIS running so that the voyage appears completely normal.

Compared to other reasons for switching off AIS, smuggling does happen but it isn’t very common.

Switching off AIS when trading with sanctioned countries

Countries that are subjected to international sanctions can be forbidden from trade. North Korea, for example, is subject to a whole range of sanctions by the majority of the world.

Despite sanctions, companies still want to accept cargos because they are getting a financial reward.

Vessels have been known to switch off their AIS, then proceed to ports in North Korea to load up on cargoes like coal. A few days later, they sail towards their destination and reactivate their AIS when clear in international waters. 

Despite turning off their AIS, authorities still track ships using satellite imagery. There is a fascinating article in The Diplomat about ships turning their AIS on and off while apparently conducting trade with North Korea: Anatomy Of A North Korean Coal Smuggling Operation.

What should you do when you switch off your AIS?

When you switch off your AIS for legitimate reasons, the ship needs to make entries into the logbook as well as reactivate it at the earliest opportunity. If the vessel is within a mandatory VTS reporting area at the time, they should also report the action to those authorities, unless there is a safety or security reason for not doing so.

The International Maritime Organisation does state what needs to be done within Resolution A.1106(29). When discussing switching off AIS, it states that:

“Actions of this nature should always be recorded in the ship’s logbook together with the reason for doing so.”

IMO Resolution A.1106(29)

Although the resolution does not state which logbook to record it in, actions of this nature would normally be in the official logbook. The reasons for switching off the AIS were to do with the safety and security of the vessel, and those sort of things should always be recorded officially.

AIS is a mandatory piece of navigational equipment, so its deactivation does impact the seaworthiness of the vessel. Insurers and surveyors will want proper documentation to prove that it was deactivated legitimately.

Can you switch off AIS when in port?

According to Resolution A.1106(29), your AIS only needs to be active when underway or at anchor.

“AIS should always be in operation when ships are underway or at anchor.”

Resolution A.1106(29)

This means that the international regulations do not require vessels to have their AIS active while in port.

Despite that, port authorities may have different rules in place that do require vessels alongside to keep their AIS running. Vessels in a particular area, like a port, have to comply with both their international obligations, but also the port’s rules and regulations. In this case, if international regulations don’t compel vessels to keep their AIS running, but the port does, the vessel must keep it running.

What are the consequences of switching off your AIS?

If you switch off your AIS and can’t justify it under the exemptions listed in Resolution A.1106(29), your vessel is no longer complying with SOLAS. SOLAS is an international convention, enacted into law by the national laws of member states. This means that should a vessel choose not to comply, they will be breaking the law of their flag state. Not only that but if they are in the territory of another nation, they will also be breaking local laws there.

Aside from the legal consequences, there are financial implications as well. Ships need to comply with international regulations to be deemed seaworthy. When a vessel stops complying with those regulations, she is no longer fit to proceed to sea. If a vessel is not seaworthy, you often find that their insurance becomes invalid.

Finally, you need to think about why AIS is considered compulsory. It improves the safety of ships, not only the ship carrying AIS but all others in the vicinity. The biggest consequence of switching off your AIS is that you are reducing the safety of your vessel and all others close to you.

When can a small boat switch off AIS?

Small boats can usually switch off their AIS whenever they want. The main exemption is if local rules apply, requiring them to have operational AIS.

According to international regulations, AIS is compulsory only on the following vessels:

  • Cargo ships >300 GRT on international voyages;
  • Cargo ships >500 GRT on all voyages;
  • All passenger ships.

Small boats fall outside of the compulsory categories, so they have no legal obligation to carry AIS at all. For this reason, they usually have Class B AIS fitted, which gives them most functions but does not comply fully with SOLAS carriage requirements. These units can be turned on and off whenever the owner wants.

What are the risks of a small boat switching off AIS?

Although small boats do not legally need to keep their AIS running, there are always risks involved in deactivating it.

You probably invested in AIS initially to improve your safety. You will have wanted to draw attention to your boat so that you are easier to see from ships and other vessels.

Deactivating your AIS removes all those safety improvements that initially prompted you to install it. Ships are required to keep a visual lookout anyway, but AIS always improves your chances of being seen. Once you switch it off, you remove those improved chances.

While there is usually no legal or financial consequences to deactivating AIS on a small boat, the risks involved are the same risks that initially prompted to you buy it anyway. You can deactivate it, but only you can decide if you should.