Q&A on Iran Tankers, Sanctions and Dark Ships


This week saw a major storm over the Persian Gulf. Literally. Heavy rains caused flooding in Saudi Arabia, Iraq and Iran.

It seems those dark clouds could also serve as a metaphor. The unusual weather for the region coincided with Washington restoring sanctions against Tehran that were lifted under the 2015 Iran nuclear deal.

The sanctions cover Iran’s energy, banking, shipping, and shipbuilding industries.

The US granted waivers to eight countries (China, India, Italy, Greece, Japan, South Korea, Taiwan, and Turkey) allowing them to keep buying Iranian oil for the next six months.

But the risk of violating sanctions by purchasing Iranian oil or facilitating illicit activity still applies to everyone else. That is a major compliance challenge.

In addition, Iranian tankers will likely have to self-insure because of sanctions and might not be able to cover the losses in the event of an accident.

“This exposes the entire maritime shipping network to immense liability,” Brian Hook, US Special Representative for Iran, told reporters Wednesday.

Following the movement of Iranian tankers around the globe became an area of intrigue for the oil market this fall and should continue until sanctions are lifted again.

I spoke with two colleagues of mine about this topic. Doug Wood is our chief scientist based in Washington, DC. John Wegrzyn is a software engineer in Ann Arbor, Michigan.

Doug and John have been monitoring activity in the Persian Gulf using data gathered from ship transponders, optical imagery and synthetic aperture radar (SAR). We began by discussing an Iranian tanker named the Navarz.

Geoffrey Craig: The Navarz was seen close to Kharg Island in September, Iran’s main export terminal, but then turned off its transponder or automated identification system (AIS). Do we know where it’s been since?

Doug Wood: It’s moved around some, but mostly been anchored near Kharg Island.

John Wegrzyn: People want to turn this into a Hollywood movie involving the nefarious shuttling of oil. But it’s much more mundane. You have tankers going from point A to point B or just sitting there.

And that’s the case with the Navarz. We have sequential images showing [the Navarz] sitting there. (See figure below) 


Source: Copernicus Sentinel data 2018, processed by European Space Agency

Image Credit: Liam Cullen/Ursa


GC: Is this optical imagery or SAR?

JW: It’s a mixture of the two. As more SAR systems come online, this type of analysis will shift to being mostly SAR.

GC: That’s an important point because the weather doesn’t always cooperate. Like this week, it’s been very cloudy in the Persian Gulf so relying solely on optical won’t work. And there have been other “dark ships” you’ve captured using the same methods, right?

JW: There was a VLCC called the Dune we saw September 12 at Kharg Island. (See figure below)



Source: Copernicus Sentinel data 2018, processed by European Space Agency

Image Credit: Liam Cullen/Ursa


GC: Yeah, the Dune looks like it’s parked at the jetty on the western side of the island. The Dune reportedly left Kharg the same day on its way to Dalian, China. There is bonded storage there. We’ve noticed other Iranian tankers doing the same thing, and that’s pushed inventories at Dalian higher.

GC: Why would a ship turn off its AIS signal?

JW: One reason is they’ve dropped an anchor or tied to a buoy. Another reason to turn off the AIS is if they aren’t worried about a collision, like in a shipping lane.

GC: I would think the opposite is true. A shipping lane sounds like the type of place you’d want to have AIS turned on.

JW: A shipping lane is like a highway. You stay in your lane and there are speed limits. A port is different. That’s like a parking lot where everyone is going in different directions and craziness ensues.

It’s also not like they’re traveling blind either because they have other instruments to help them, like navigational radar, to avoid collision. And sometimes the captain doesn’t want to bother with the AIS chirping away so he shuts it off.

There isn’t an international standard for AIS usage or strict global enforcement. So the usage of AIS is a really a patchwork of regional laws and up to the discretion of the captain.

DW: One reason to turn the AIS on is to talk to someone and they need to find the other boat’s call sign. Then they turn it back off.

JW: If a ship isn’t transmitting AIS and not running navigational radar then that’s a red flag.

DW: Ships have radar to avoid other ships. If they decide to go truly dark, then they would need to turn off all radar and trust that they can visually avoid other ships. That’s risky stuff. It’s provocative.

JW: It doesn’t matter why there isn’t AIS information on any given ship. Anybody basing their economic decisions only on AIS is asking for trouble because without diversifying their information stream they are vulnerable to outages or someone disrupting this information stream.

GC: That’s where SAR comes in. It’s all-weather, day and night.

JW: Right. Whether counting ships or tracking flows or making statements about ship-to-ship transfers, SAR is another data source to help fill the void.

Understanding the pattern of life in the Persian Gulf is also important. You need to know whether all ships from China, for example, usually go to dock or do some do a ship-to-ship transfer, and if so how is that recorded? If it’s not recorded in an import log then you have something interesting.

GC: Are there any limitations to using SAR? Can you identify what you’re looking at? It seems like it would be difficult to identify the specific tanker.

JW: It’s like taking a picture and recognizing a face. You can do a similar thing with ships. Everything has a fingerprint. When we get 3-D models and enhance SAR processing, this will help us confidently match an image of a ship with its name. That’s a capability being developed.

GC: Exciting stuff. Doug and John, thanks for your time.