Iran and the Houthis have been tapping into the Automated Tracking System (AIS) to locate and attack ships in the Red Sea and, since Saturday, December 23rd, ships in the Indian Ocean. Where AIS lacks information on military ships, Iranian radars do the job of finding them. The entire operation is sophisticated and is managed in real time, requiring significant assets to identify targets. There is no doubt that Iran and the Houthis are working together.
AIS is a system onboard ships that reports the ships name, location, position, course and speed. The AIS system is linked to the ship’s gyro compass, rate of turn indicator, and GPS. The resulting information is received by other ships, sent to coastal relay stations and can also be transmitted to AIS-enabled satellites. Around 99% of commercial ships worldwide use the AIS system. The system is mandated by the International Convention for the Safety of Life at Sea or SOLAS.
A few months after the Fitzgerald accident, the US Navy decided to use AIS in high traffic areas.
Some commercial ships turn off their AIS in areas where there is either a threat of attack or hijacking. However, doing so in high traffic areas like the Red Sea invites the chance of a serious accident and compromises insurance policies for ships and cargo.
There are a number of online, public AIS trackers that cover civilian and military ships. One of them, Cruising Earth features a separate section to track military ships from many nations, including the United States. Checking on the US ships that have been identified as involved in Red Sea operations, the USS Carney, USS Mason and, most recently, the USS Laboon (all Arleigh Burke class AEGIS-equipped destroyers) reveals that none of them have their AIS system operating.
The USS Mason was last reported on AIS on November 30th in the Gulf of Aden. There are no reports since that date and the vessel is listed as “out of range.” The USS Carney last reported AIS location was on December 12th, 2022 on the east coast of the United States. The USS Laboon, which just shot down two Houthi missiles, was last reported in the Sea of Azov on June 18, 2021. What this means is neither the Iranians nor the Houthis can use AIS to track US warships.
However, that limitation does not apply to other methods of finding US warships and certainly does not protect commercial ships using AIS which can be actively tracked, by name, by the Iranians and Houthis. By reading ship registration records, Iranian intelligence can figure out which ships have all or partial Israeli or other foreign ownership, and tag them so when they enter an area within reach of drones or missiles, they can be attacked. The Iranians may also have access to non-public records, although exactly what they are and how they are accessed is not yet known.
Those attacks now include the Indian ocean and the attack on December 23rd by a Iranian drone against the Chem Pluto, a “Liberia-flagged, Japanese-owned, and Netherlands-operated” chemical tanker was hit “by a one-way attack drone fired from Iran” some 200 nautical miles (370km) off the coast of India, according to the US Defense Department. A British maritime security firm, AMBREY, however says the Chem Pluto has some Israeli affiliation. It is not clear as to the source of Ambrey’s information. The public record on the ship shows it is owned by S S Offshore Pvt Ltd, a small firm in Mumbai, India. A check on Maritime Tracker shows that the ship (as of this writing) is off the west coast of India and is not under command, meaning it is under tow.
The above suggests that culling intelligence on ship ownership requires considerable effort. The Iranians have put a significant effort into picking out the targets, going well beyond easily obtained information.
Exactly how the Iranians and Houthis knew about Chem Pluto’s possible Israeli ownership is not clear, but Chem Pluto was certainly broadcasting its location using AIS (as the current tracker shows). The ship was hit by a drone, reportedly a KAS-04 made by Iran’s Kimia Part Sivan Company (KIPAS). This drone is both a surveillance drone and a loitering munition. It has long range, but is slow flying, using a single pusher propeller.
US Central Command believes that the Houthis are assisted by Iran in locating US warships in the Red Sea. The Iranians have positioned a spy ship (masquerading as a civilian ship), the MV Saviz. According to US government sources, the MV Saviz is equipped with intelligence domes and antennas. The ship carries 3 speedboats which provide untraceable communications with Yemen.
MV Saviz has been on station for a number of years and Israel has tried to destroy it.
At one time Yemen had high-end coastal radars (made by Italy’s Finmeccanica, now Leonardo), but these were apparently destroyed by US Tomahawk missiles in 2016 after the Houthis overtook the Red Sea coastal area.
The liquidation of these radars means that it would be impossible for the Houthis to locate US warships without additional help. That means the MV Saviz is very important because it has high end radars and can intercept communications from US warships.
Clearly the Houthi-Iran effort is not something ginned up on the spur of the moment. It seems the attack on both commercial ships and US warships is part of a highly planned and well coordinated effort, the collection of information not always readily available (such as ship’s ownership) and the ability to coordinate AIS tracking with radar-derived and communication’s intelligence.
Sooner or later the US and its partners will need to deal with the threat to commercial and military ships, in the Red Sea and Indian Ocean. Furthermore, Iran has announced it may extend the threat to the Strait of Gibraltar and the Mediterranean Sea.