Iran's Shahed-136 drone has been reconfigured by Russia into a more efficient weapon. Image: Iranian Ministry of Defense

An oil tanker owned by an Israeli billionaire was hit by a suicide drone off the coast of Oman on November 15. 

Israeli government experts believe the drone that struck the tanker was an Iranian Shahed-136 and suspicion immediately fell on Tehran as the likely perpetrator. 

Initial reports say no one was injured and, while the drone punched a hole in the ship, no oil leak was reported. This is lucky since the drone has an 80-kilogram (177-pound) warhead that can exact considerable damage.

It is not the first time the Iranians have targeted Israeli-owned oil tankers but it is the first time Tehran has used a drone instead of a missile or limpet mine.

The stock version of the Shahed drone is not known to be capable of hitting moving objects as it has no camera, radar or other onboard sensor. 

How, then, did the drone identify and strike the Israeli tanker? Is there reason to be concerned about the future of safe transit in the Persian Gulf and Red Sea or other sensitive areas including the Black Sea and the Mediterranean?

The Shahed-136 has been sold by Iran to Russia, apparently in the thousands, and is being used primarily against Ukraine’s critical infrastructure.

The drone itself is made up mainly of Western electronics (mostly American) mounted on five custom circuit boards, and has a Mado (originally German) MD-550 four-cylinder gasoline engine claimed to be made in Iran but may be produced in China.  

When the Russians got the Shahed-136 from Iran, they replaced the drone’s accuracy-challenged inertial navigation system with a Russian GLONASS satellite navigation system. Russia renamed the modified Shahed-136 the Geran-2. 

There is reason to believe that the drone that struck the Israeli-owned oil tanker was a modified Shahed-136, suggesting that the improvements made by the Russians have been incorporated into Iranian production.

Iran still has outstanding orders from Russia for more Shahed-136 drones, to be deployed in the war in Ukraine.

The Iranian Shahed-136 loitering drone has been deployed by Russia in Ukraine. Image: Tayeb Mezahdia / Pixabay

The Israeli-owned tanker was hit by a drone fired around 240 kilometers from shore, meaning that, at minimum, the location of the tanker exceeds the range of the original Iranian Shahed-136 drone, which before Russia modified it, was between 170 and 200 kilometers. 

Because the Shahed has no camera or other sensor to locate targets, it must be programmed before launch with target coordinates. 

The Russian modifications made it possible to work over a longer distance using the same engine. Russia says the Geran-2 range is now 1,800 to 2,500 kilometers.

At the same time, the modifications probably also made it possible to program the drone while it’s in flight. That means coordinates could be sent to the Shahed-136 from a nearby aircraft, drone or ground station command post.

Even so, without a way to steer the drone, the Russians say that the Shahed-Geran is only capable of hitting fixed targets since the drone cannot see the target and adjust its flight path. How, then, can it hit a moving oil tanker?

A modern ship, commercial or military, is equipped with an automatic identification system (AIS). AIS broadcasts the ship’s identification, position, course and speed. An AIS transponder transmits updates every few seconds.

The transponder provides real-time vessel position and carries out automatic calculations enabling ships at sea to avoid collisions. AIS is designed to prevent accidents and, in the worst cases, to provide urgent location information for rescue operators. AIS is used around the world today.

If thShahede -Geran is capable of receiving real-time targeting information, as opposed to updated information on fixed targets, its flight path may be adjusted against a moving ship at sea. Since almost anyone can receive AIS information, the missing ingredient is to feed that information from the AIS into the drone. 

If the Russians already extended the drone’s range, then they likely have put in a receiver to update target information sent from either a ground location or another drone. It is this capability that the Iranians, and perhaps also the Russians, are exploiting.

The Shahed-136 costs approximately US$20,000. Modifying it with GLONASS and a receiver for AIS data should add only a few thousand dollars to the cost. Thus a modified Shahed-136 would be a cheap weapon against an oil tanker. New oil tankers cost over $100 million, not counting the oil being hauled.  Even old tankers that are still efficient are pricey.

It would make sense that both the Iranians and Russians are exploiting AIS. The Russians could use the modified Shaheds in the Black Sea against commercial and military ships. 

Given Ukraine’s long-range missile capabilities that allow it to hit Russian warships, a suicide drone in Russian hands has significant advantages and will likely be seen over the Black Sea in the future.

Ukraine has used the High Mobility Artillery Rocket System (HIMARS) to devastating effect on Russian targets. Image: Facebook

Similarly, the Iranians could use modified Shahed drones in the Persian Gulf and Red Sea, perhaps with the help from their militant Hezbollah and Hamas proxies, to threaten Israeli commercial and military naval assets.

Shahed-136 drones are hard to intercept. They have a small radar signature and hardly any heat (infrared) signature. Commercial ships have almost no defenses against drones. Even a military ship would need to have capable air defenses and an ultra-alert crew.

There is reason for concern about Iran’s drones, and Washington and NATO, as well as the Gulf States and Israel, need to pay closer attention and take action to deal with the emerging threat of cheap suicide drones at sea.

Stephen Bryen is a senior fellow at the Center for Security Policy and at the Yorktown Institute. Follow him on Twitter at @stevebryen