Welcome back to the MBN Iran Briefing.
Two months into the war, the Strait of Hormuz remains closed, peace talks have stalled, and the U.S. naval blockade of Iranian ports is entering its third week with no end in sight. This week we look at what is actually happening at sea and why the naval dimension of this war is more complicated than it appears.
Find out more below.
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And don’t forget to check out the latest Iran Briefing podcast. In this edition: U.S. President Trump extended the ceasefire, without any new deadlines. The sons and daughters of Iran’s ruling elites find their high life in the West imperiled. Iran goes on a meme offensive, waging information war in the region and beyond. Roya Hakakian, Matt Kaminski, and yours truly explore what’s going on. Watch here or listen here.
Quote of the Week
“In an asymmetric war, similar to the Vietnamese during the Vietnam War, Iranians have advantages beyond what the Americans could comprehend. They understand that the U.S. could drop thousands of tons of bombs, but it does not possess the patience to withstand a prolonged war. Like the Vietnamese revolutionaries, the Iranians appear ready to fight a protracted war with much sacrifice of national resources. Iran, in other words, understands the Achilles’ heel of the U.S.”
— Hai Nguyen, co-founder and director of the Global Vietnam Wars Studies Initiative at the Harvard Kennedy School
TOP OF THE NEWS
War at Sea
The war on Iran has been fought on many fronts: in the air over Tehran, in the corridors of diplomacy in Islamabad, in the power struggles inside the Iranian regime. But the sea may be where the outcome is actually decided.
Iran closed the Strait of Hormuz within hours of the first American strikes on Feb. 28, and the struggle to control it has become the defining feature of the war. What followed was not the swift assertion of maritime dominance the opening campaign promised.
MBN Iran Briefing Podcast
Expert conversations unpacking the latest developments in Iran and how they are reshaping security, energy markets, and geopolitics across the Middle East.
On Paper, Not a Contest
On paper, the contest at sea is not a real contest. The U.S. has three carrier groups in the region, dozens of warships, and submarines capable of striking anywhere in the ocean. And yet the Strait of Hormuz remains effectively closed. Commercial shipping has not returned. The International Energy Agency has described the conflict as triggering the most severe oil supply shock in history, with Brent crude trading above $107 a barrel.
Thousands of seafarers are trapped in the Gulf. Both sides are now seizing each other’s ships, firing on third-country vessels, and mining and demining the same waterway simultaneously.
An F/A-18E Super Hornet launches from the flight deck of the USS Abraham Lincoln. Photo: Reuters
The U.S. Deploys
Only four or five of the U.S. Navy’s eleven carriers are currently available for combat operations globally, and three of those are now committed to this conflict. The USS Abraham Lincoln was pulled from a Pacific deployment and redirected west, arriving in the Indian Ocean a month before the war began. The USS Gerald R. Ford followed in February, arriving from the Caribbean, where it had been supporting U.S. military operations against Venezuela. The third carrier, the USS George H.W. Bush, left Virginia in late March and sailed around the southern tip of Africa to avoid the Red Sea. This detour was itself an admission that even the world’s most powerful navy was routing its ships around the Houthis, a proxy force it hadn’t neutralized.
The first two carriers came to destroy Iran’s military capacity, and the naval campaign was central to that from the opening hours. The first Tomahawk strikes targeted Iranian naval forces across the southern flank before any other action was taken. The priority was eliminating Iran’s ability to threaten Gulf shipping before Tehran could exercise those options.
The destruction was significant. U.S. forces put more than 120 Iranian vessels out of action, including Iran’s drone-carrying converted container ship, commissioned only a year before the war. By mid-March, an entire class of Iran’s most advanced missile corvettes had been confirmed destroyed. One of the war’s most striking naval moments came when an American submarine sank an Iranian frigate off the coast of Sri Lanka: the first time since World War Two that a U.S. submarine had destroyed another vessel using a torpedo. There was no safe harbor for Iranian warships anywhere in the wider ocean. In the words of CENTCOM commander Admiral Brad Cooper, the U.S. sank “the Iranian Navy – the entire Navy.” Iran’s foreign minister warned that the U.S. would “bitterly regret the precedent it has set.”
The campaign also revealed the limits of American endurance. When fire broke out aboard the Gerald R. Ford while it was operating in the Red Sea, the U.S. Navy’s initial statement said the ship remained fully operational – a claim later contradicted when it was confirmed the carrier could not fly sorties for two days after the fire was extinguished. The blaze displaced roughly 600 sailors and took 30 hours to bring under control. By that point the carrier had been at sea for more than 300 days, longer than any carrier since the Cold War. A fire in a laundry room grounding America’s most capable carrier mid-campaign was a reminder of what sustained high-tempo operations can undergo, even the most powerful platforms.
A U.S. Navy sailor on a destroyer during Operation Epic Fury. Photo: Reuters.
The U.S. Commitment
When the Apr. 7 ceasefire paused the U.S. and Israeli air campaign, the U.S. Navy’s focus shifted from destruction to economic strangulation.The three carrier groups now operating in the region simultaneously mean that this is the first time since the 2003 invasion of Iraq that the U.S. has maintained that level of naval presence in the Middle East. The total force represents approximately 41 percent of all U.S. Navy ships actively deployed worldwide. An estimated 33 percent of the entire available destroyer fleet is committed to this single theater.
Senior military officials have said publicly that the sustained commitment of forces here is affecting American readiness and deterrence capacity everywhere else in the world. Ships committed to Hormuz are unavailable anywhere else a crisis might demand them – such as the Taiwan Strait, the most likely site of a major conflict. Some analysts have noted that Iran has demonstrated something strategically significant: How a weaker state can limit the operations of the world’s most powerful navy despite losing most of its own naval and air forces in the war’s opening days — a result with potentially important implications for other contingencies, including a war over Taiwan, though experts caution the two theaters differ considerably.
The Houthis have not attacked commercial shipping in the Red Sea since the war began, though they fired ballistic missiles at Israel in late March. The Houthis have held back their most economically disruptive capability while retaining it as leverage. Should the ceasefire collapse, a second chokepoint at the mouth of the Red Sea becomes available almost immediately. Two simultaneous chokepoint closures would represent an energy shock without modern precedent.
A missile is launched during an exercise of the IRGC navy. Photo: Reuters
Unsinkable Navy
An important distinction in this conflict is between Iran’s naval threat and Iran’s navy. They are not the same thing. Most of the vessels the U.S. destroyed belonged to Iran’s regular armed forces. The Islamic Revolutionary Guard Corps maintains its own separate asymmetric naval force, built specifically for combat in the Strait of Hormuz, much of which remains intact. This force has been designed around a specific operational concept: dispersion, speed, and volume rather than large capital ships. Fast-attack craft, suicide boats, and a “mosquito fleet” built for asymmetric combat in the strait’s cluttered littoral environment have as a strategic objective denial, not control.
The degradation of Iran’s conventional fleet has not given the U.S. complete maritime control, because the operational center of gravity has shifted to the strait.
Mines are central. Iran has deployed sensor-equipped mines in the strait, including modern designs optimized for shallow water that are difficult to detect by sonar. No ship has been confirmed to have been struck by a mine, but the strategic impact is disproportionate. The mere presence of mines, combined with persistent drone and fast-boat threats, makes the risk of transiting high enough that commercial operators will not take the chance. Iran has also demonstrated that older technologies, artillery among them, remain effective asymmetric tools alongside newer capabilities like uncrewed speedboats, together constituting a layered harassment campaign that the U.S. has not been able to shut down.
The U.S. approach to the blockade has been characterized by naval analysts as a “distant” rather than traditional “close” blockade, offering less tactical risk against Iran’s fast-attack craft, mines, and coastal cruise missiles, but at the cost of only partial control over a far wider operational area. The U.S. can dominate open water, but the strait is not open water. It is, rather, a narrow, shallow, high-traffic chokepoint that favors the defender.
An electronic warfare aircraft launches from the flight deck of the USS Abraham Lincoln during Operation Epic Fury. Photo: Reuters
The Standoff
What is unfolding in the strait right now is two simultaneous blockades, each side trying to strangle the other, with the world’s oil supply caught between them. On Apr. 19, U.S. forces fired on and seized an Iranian cargo ship after it ignored blockade warnings for six hours. Iran called it piracy. Three days later, the IRGC seized two foreign container ships attempting to exit the Gulf and attacked a third that escaped. Neither vessel had any connection to the U.S. or Israel. CENTCOM said today that the blockade has prevented 38 ships from entering or leaving Iranian ports, with U.S. forces boarding tankers linked to Iran’s shadow fleet deep into the Indian Ocean.
Iran has also attempted to convert the strait into a revenue stream, charging tolls of over a million dollars per vessel to ships it permitted to transit. It is now pressing Oman to support a formal toll mechanism in order to turn the strait into a longer-term instrument of economic leverage by reshaping the rules of the waterway after the war ends.
By blockading the strait, Washington is attempting to deny Tehran its strongest source of economic leverage, but risks exacerbating rising energy prices and contributing to global financial instability in the process. The U.S. Navy has begun clearing Iranian mines from the strait, a project the Pentagon says could take up to six months.
After the War
Unless Iran’s regime collapses, the Strait of Hormuz may never revert to its pre-war status, because Tehran has now discovered how much leverage it can wield over the global economy and might not willingly surrender it. Gulf states are already accelerating efforts to reduce their Hormuz dependency. The UAE aims to cut its exposure from roughly 50 percent of oil exports to zero over the next two to three years.
The agreement that eventually ends this war may also reveal a divergence that has been apparent throughout the conflict: A settlement that satisfies Washington by addressing maritime threats and nuclear constraints may fall short of what Israel requires if it leaves intact Iran’s missile arsenal and proxy networks. The naval campaign has been conducted largely in the service of U.S. strategic objectives, but it’s not obvious those objectives and Israeli ones converge in the endgame.
Who Is Winning
The United States has the larger and more lethal navy, and has used it to devastating effect against Iran’s conventional forces. Iran has used what remains – including mines, drones, fast boats, and the persistent threat of more – to keep the strait functionally closed for nearly two months.
Iran does not need to control the Strait of Hormuz militarily. It only needs to make the risk of transiting high enough that commercial operators will not take the chance, and it has already done that. If the U.S. does not develop the capability and credibility to counter this threat durably, what is now a short-term disruption risks hardening into a permanent feature of the global energy system.
While Iran’s navy has been broken, its strategy has not. The side with fewer ships is not losing the war at sea.
A U.S. Marines F-35C Lightning II prepares to launch from the flight deck of the USS Abraham Lincoln during Operation Epic Fury. Photo: Reuters
ESSENTIAL READING
Iran’s Strait of Hormuz Gambit and the Limits of U.S. Military Power. CSIS (Daniel Byman) – April 20, 2026. The definitive think tank take on the naval standoff, arguing that the “blockading the blockaders” strategy has created an equilibrium that neither side can easily escape, and that U.S. and Israeli end goals may not be as aligned as they appear.
The Strait of Hormuz Under Pressure: Asymmetric Naval War and Signs of Elite Fragmentation in Iran. Hudson Institute – April 24, 2026. Explains why destroying most of Iran’s conventional navy has made surprisingly little difference: the IRGC’s surviving “mosquito fleet” of drones, mines and fast attack boats is purpose-built for the strait’s geography and resists decisive destruction.
FPRI Experts React: The US Blockade of the Strait of Hormuz. Foreign Policy Research Institute – April 13, 2026. A naval doctrine roundtable distinguishing the U.S. “distant blockade” from a traditional close blockade, assessing its tactical advantages and the risks of Iran countering with swarm attacks.
A Conflict of Attrition: Iran’s Bet on Asymmetric Warfare. Bulletin of the Atomic Scientists – April 7, 2026. Makes the broader strategic case that Iran’s success in denying freedom of navigation to the world’s most powerful navy despite losing most of its own fleet offers uncomfortable lessons for how the U.S. might fare in a Taiwan Strait scenario.
From Maritime Trench Warfare to a ‘Sloppy Peace’: How the Strait of Hormuz Standoff Could Play Out. Fortune / Goldman Sachs Global Institute – April 25, 2026. The most forward-looking of the five articles, arguing that regardless of how the conflict ends, the Strait of Hormuz will never fully reopen on pre-war terms and that Gulf states are already planning to make it strategically irrelevant within three years.
Andres Ilves
Andres Ilves is Iran Editor and Senior Adviser at MBN. His career as a journalist and writer includes two decades at the BBC and Radio Free Europe.
