While most of Iran’s conventional naval warships could be destroyed, analysts say that’s far from where Iran’s true naval power lies.
The country’s ability to reliably threaten commercial shipping transiting the Strait of Hormuz actually rests on a multilayered array of low-cost, unconventional combat systems: fleets of drones, mines, and small attack craft that are more difficult to detect than traditional naval assets.
These small vessels, dubbed the “mosquito fleet” by military analysts, are deployed by the Islamic Revolutionary Guards Corps (IRGC), and importantly, the missiles, guns, and other weapons they can deploy pose a major strategic challenge for the U.S. military as it seeks to mitigate threats across vast oceans.
This is essentially a guerilla war on the water, and geography also favors Iran, as there are no alternative routes for ships that need to pass through the difficult waters of the narrow Strait of Hormuz.
“Ultimately, the number of ships required for regional defense of merchant shipping will be significant,” said Sidharth Kaushal, senior seapower researcher at the Royal Defense Institute (RUSI) think tank. “And of course, that can be very resource intensive.”
The use of small boats by the Revolutionary Guards goes back decades, especially after the U.S. military proved capable of crippling Iran’s traditional navy during operations in the Persian Gulf in 1988. Since then, “the regular Iranian navy has always been something like a drill ground force, whereas the Revolutionary Guards navy, built around asymmetric assets that the Iranians thought could actually help in the war effort… has always been a strategically more important asset,” Kaushal said.
These small skeleton crew ships and drone boats are so close to the waterline that they are “very discreet,” so radar systems often detect them until it’s too late, the analyst said. To effectively track these threats, the United States needs to deploy assets such as helicopters and drones.
The Revolutionary Guards Navy also reuses civilian vessels, such as fishing dhows, for clandestine operations such as minelaying, complicating any surveillance efforts, according to a report by the Washington, D.C.-based Hudson Institute.
“This entire structure is designed to impose friction and attrition rather than to seek or win decisive naval engagements,” the Hudson Institute noted.
“The IRGCN (Navy) designs and manufactures vessels to maintain affordability, avoid sanctions, and be easily replaced in times of war,” the report states. This approach allows Iran to put other countries’ ships at risk “at relatively low cost, while endangering the enemy’s high-value assets and the global maritime economy.”
What is Iran’s “mosquito fleet”?
What some military experts call Iran’s “mosquito fleet” is causing chaos in the Strait of Hormuz. CNN’s Nick Robertson explains why this fleet of small boats is so effective.
Some of Iran’s asymmetric threats, such as the mines themselves and so-called “mini submarines,” are easier for the U.S. Navy to combat. These small “midget” submarines tend to operate from Iran’s well-known ports, making them easier targets for the United States if it so chooses, Kaushal said.
Additionally, the United States has unmanned undersea vehicles that can be deployed to scan the ocean floor and identify mines, Brian Clark, a senior researcher at the Hudson Institute, said in an interview with CNN. However, identifying entire transport routes that are safe from landmines is a time-consuming and arduous process.
Meanwhile, Iran’s layered strategy also means the U.S. Navy must be on guard against anti-ship missile launchers hidden in hundreds of miles of rocky mountainous terrain along the country’s southern coast. Analysts say these missile batteries are mobile, making them difficult to remove, and the long Gulf coastline means Iran could strike from far across the strait itself.
“This combination of (capabilities) and complexity creates quite a problem,” said Nick Childs, a senior maritime security fellow at the International Institute for Strategic Studies. He said the problem mosquito swarms pose for the U.S. military and commercial vessels is that “you can never be completely sure that something might not be able to get through.”
“Most of the attacks we’ve seen recently that have actually caused damage to ships have been missiles, and probably ‘suicide’ drones as well, but it’s mines and fast attack craft that are eating away at people’s minds,” Childs said.
According to the latest data from the UK Maritime Trade Operations Center (UKMTO), 26 ships have been attacked by Iran in the Strait of Hormuz and the Persian Gulf since the start of the war.
“Another factor is, on a more strategic level, the Iranians don’t actually need to score many hits; they just need to score enough hits on their shipments to convince insurance companies and ship owners that they don’t want to risk the lives of both crew and cargo,” Kaushal added. “So in some ways, the demands on the U.S. Navy are much higher than the demands on Iran.”
President Donald Trump said Tuesday that the United States will end short-term efforts to “direct” ships through the Strait of Hormuz, but will maintain a blockade of Iranian ports. U.S. Central Command said in a statement Monday that two U.S.-flagged commercial ships passed through the strait as U.S. forces eliminated the Iranian threat, but there was little sign of a meaningful increase in overall shipping traffic through the strait.
Iranian state media characterized the move to halt the operation as a “failure of the United States.”
Meanwhile, Iran this week launched a new regulatory body to control traffic in the strait as part of a plan to impose high tolls for safe passage. On May 1, the U.S. Treasury Department issued an advisory stating that shipping companies could face sanctions if they choose to pay tolls to the Iranian regime.
Iran and the United States engaged in another exchange of fire on Thursday despite a ceasefire. President Trump said U.S. forces had destroyed an Iranian attack force that targeted three U.S. Navy destroyers transiting the strait, and warned that if Iran didn’t sign the deal soon, “we’re going to defeat them harder and more violently.”
CNN’s Henry Zellis, Alejandra Jaramillo and Irene Greif contributed to this report.
