The Evolution of the Tanker War in the Persian Gulf

Oil Tanker
Credit: Dimitris Vetsikas / Pixabay

On July 30, 2021, the tanker Mercer Street was attacked by a suicide drone off the coast of Oman. Mercer Street is a Liberian-flagged, Japanese-owned vessel operated by London-based, Israeli-owned Zodiac Maritime. The attack resulted in two fatalities, a British citizen, and a Romanian citizen. The same day the tanker’s crew also reported an earlier failed drone attack, in which the attacking drone fell into the water. Unsurprisingly, the US, UK, and Israel blamed Iran for the attack, while Iran rejected the accusations as baseless, and dismissed such claims as an Israeli conspiracy.

The attack on the Mercer Street is the latest in a spate of attacks and alleged covert operations against merchant shipping and warships in the Persian Gulf. Earlier on June 02, 2021 the oil tanker Kharg, Iran’s largest warship, caught fire and sunk under mysterious circumstances in the Sea of Oman. Iran did not issue an official statement attributing the loss of Kharg to any other country but looked at the incident from multiple angles, such as technical problems or internal sabotage but did not rule of the possibility of an attack. Yet another earlier attack happened on June 14, 2019, when the oil tankers Front Altair and Kokuka Courageous were damaged by naval mines off the Strait of Hormuz.

Although attacks on oil tankers in the Persian Gulf have been a staple regional concern since the 1980-1988 Iran-Iraq War, the recent attacks differ from attacks on tankers during that conflict, and have significant military, political, and regional implications.

Historical Differences Between the First and Second Tanker Wars

The term Tanker War is commonly applied to the spate of mutual attacks by Iran and Iraq on each other’s merchant shipping and eventually international shipping in the Persian Gulf during the Iran-Iraq War. For the sake of discussion, the Iran-Iraq Tanker War will be referred as the First Tanker War, and the contemporary trend of attacks on oil tankers in the Persian Gulf as Second Tanker War.

During the First Tanker War, Iraq’s war aims were to cripple Iran’s ability to export oil and bring in the US and other world powers to intervene on its behalf. Tanker War can be divided into two phases. The first phase began in May 1981, when Iraq began to use combat aircraft armed with anti-ship missiles to attack all ships going in and out of Iranian ports in Persian Gulf. The second phase began in 1984, when Iraq intensified its attacks, and Iran retaliated using unconventional tactics such as swarms of fast attack boats and naval mines to offset its lack of anti-ship missiles. The First Tanker War came to an end with Operation Praying Mantis. On April 18, 1988, the US Navy largely destroyed the Iranian Navy’s combat capability by sinking a total of six ships, including major surface combatants such as a frigate and a gunboat. These losses composed almost half of the Iranian Navy’s operational fleet at that time and ensured that the Iranian Navy would not mount any significant sorties until the end of the Iran-Iraq War.

The Second Tanker War differs from Tanker War 1.0 in many aspects. First, Tanker War 1.0 was between Iran and Iraq, with the later intervention of the US. The Second Tanker War on the other hand can be framed as part of a larger proxy conflict between Israel and Iran. Iraq was destroyed as a regional power during the 2003 US invasion, and is almost under complete Iranian domination, making it a possible Iranian staging ground for the Second Tanker War.

Second, there are also significant differences between the strategic goals of the First and Second Tanker War. In the First Tanker War, Iraq aimed to cripple Iranian oil exports and bring the US and other external powers to intervene on its behalf. But in the Second Tanker War, Israel may be attempting to destroy Iran’s ability to supply its regional proxies in Yemen, Syria, Gaza, and Lebanon. In turn, Iran may be seeking to retaliate against Israeli covert operations aimed at crippling its nuclear program and expand its strategic and operational options by opening a naval front in its proxy conflict with Israel.

Third, the First Tanker War was a conventional state-to-state conflict, with Iran and Iraq being officially at war with each other, using clearly identifiable combatants during hostilities. In contrast, the Second Tanker War features extensive plausible deniability measures by Iran and Israel, as both countries are not officially at war, but are openly hostile to each other. As such, hostilities between the two are characterized by covert operations using unmarked drones, special forces, intelligence agencies, and proxy militias to carry out attacks.

Military, Political, and Regional Implications

Military technology has advanced considerably since the events of Tanker War 1.0. The Internet, Artificial Intelligence, and unmanned systems have fundamentally changed the nature of warfare. The attack on the Mercer Street is notable since it is the first known use of a suicide drone against a ship, becoming an unfortunate proof of concept that suicide drones can be used against naval targets. This has significant implications as it has shown that suicide drones can act as a “poor man’s cruise missile” in naval warfare. Their low cost, relative ease of manufacture, and potential destructiveness make them a feasible anti-ship missile substitute for irregular forces or navies with limited budgets. When combined with autonomous attack capabilities that allows them to fly, patrol, identify, and engage targets independently, these suicide drones can turn into potent tactical standoff and area denial naval weapons.

In political terms, the attack on Mercer Street may be a part of Iran’s efforts to pressure the US and its allies to resume JCPOA negotiations. The more the US and its partners impose economic sanctions on Iran and keep a hard line in negotiations to cripple its conventional military capabilities, the more Iran is forced to rely on asymmetric warfare strategies, such as the use of proxy militias, missile build-up, and pursue its nuclear program to defend its security interests. In a way, these asymmetric means of power projection can cause more regional instability in the Middle East, compared to allowing Iran to have sufficient conventional forces for self-defense. Also, the attack shows that the new Iranian President Ibrahim Raisi can be unpredictable in terms of his foreign policy. However, it is too early currently to tell the trajectory of President Raisi’s foreign policy. He may continue his predecessor President Hassan Rouhani’s diplomatic approach towards the West, or he can be a hardliner in the same way as President Mahmoud Ahmadinejad was.

From a regional security aspect, the drone attack on the Mercer Street can possibly show that Iran has successfully extended its power projection efforts to the Red Sea and Horn of Africa. It is not clear from where the drone attack on the Mercer Street was launched. The only plausible launch locations for such an attack would be in Iran’s hidden naval bases along its side of the Strait of Hormuz, and from its Ansar Allah allies in Yemen. If the drone was launched from Yemen, it shows that Iran has successfully enabled its proxy to perform extended sea denial along the Suez Canal, Red Sea, and Horn of Africa, in addition to creating a credible threat next to its regional rival, Saudi Arabia.

While attacks on oil tankers in the Persian Gulf have been a long-running regional security concern, the attack on the Israeli-owned Mercer Street has significant military, political, and regional implications. One crucial variable that may influence how this trend evolves is the US military refocus from the Middle East to the Indo-Pacific. With a smaller US military presence in the Middle East, states such as Saudi Arabia and Israel are faced with two options.  First, they can decide to support negotiations aimed at reducing sanctions against Iran in exchange for curbing the latter’s support for its proxies, controlling its missile build-up, and scaling down its nuclear program. Second, Israel and perhaps Saudi Arabia may pursue aggressive courses of action independently of the US to make up for the reduced US military footprint in the region, and combat Iran’s growing influence in the Middle East.

Gabriel Honrada is a PhD student studying International Relations at the Peoples’ Friendship University of Russia. He focuses on security and military affairs.

Daniyal Ranjbar is a PhD candidate of the Peoples’ Friendship University of Russia in the specialty of International Relations, focusing on sanctions policy.