Everything you need to know about the Strait of Hormuz

About 20% of the world’s oil supply travels through the Strait of Hormuz. The Iran War threatens to cut it off. The history of the Strait of Hormuz, who controls it and how it became so critical to the global oil supply.

Rudi Matthee, professor of Middle Eastern History at the University of Delaware. Author of four-prize-winning scholarly books on Iranian history.

Sal Mercogliano, maritime historian at Campbell University. Adjunct professor at the U.S. Merchant Marine Academy. He hosts the show “What's Going on With Shipping?” a YouTube channel that looks at maritime industry policy, current events and history.

Mark Allen, professor of Earth Sciences at Durham University.

The version of our broadcast available at the top of this page and via podcast apps is a condensed version of the full show. You can listen to the full, unedited broadcast here:

 Part I

MEGHNA CHAKRABARTI: I'm Meghna Chakrabarti with you today from WABE in Atlanta, Georgia. When we asked you to let us know what you want to learn about the U.S. and Israel's war with Iran, many of you wanted to know a lot more about what has always been a critical but is now the most important waterway in the world, the Strait of Hormuz.

Among your questions, Nancy Sue in Sedalia, Colorado asks if the U.S. is taking over the Strait. And is that part of the Trump administration's motivation for the war? Joshua Morgan in Michigan wants to know if Iran has really mined the Strait. Pete Peterson in Charleston, South Carolina asks if there are alternatives for getting oil out of the Gulf region.

Celia from Santa Fe, New Mexico wants to know more about the negotiations between Iran and other nations such as India or China to get oil through the Strait. Those are just some of the questions you had about this highly consequential narrow band of water. So let's begin at the beginning, which happens to be some 35 million years ago. Because geology is what laid the foundation for the political crisis we have today, and that comes with the collision of the Arabian and Eurasian tectonic plates.

MARK ALLEN: There was an ocean that's now vanished called Tethys, which disappeared as one side of it dived down under the southern side of what at the time was the Eurasian plate, and eventually it brought the northern end of what we call the Arabian plate into contact with that Southern Eurasian margin.

CHAKRABARTI: Mark Allen is a professor of Earth Sciences at Durham University in England.

That tectonic collision happened in what is today Eastern Turkey, Northern Iraq, and Western and southern Iran.

ALLEN: It's like imagining a slow-motion car crash that those two plates, Arabia and Eurasia have kept moving towards each other at a rate of around 20 millimeters a year. So a bit less than an inch a year for the last 30 odd millions of years.

And that means an enormous amount of crumpling has taken place in both continents and it's thrown up the mountains that now occupy much of the territory of Iran.

CHAKRABARTI: That would be the Zagros Mountains, which stretch for 990 miles through Iran, Iraq, and Turkey. Now, critically, these two colliding tectonic plates were constituted of what's known as source rocks.

Now these are organic rich sedimentary rocks like shale or limestone. That I said are rich in hydrocarbons. And when subjected to enormous temperature and pressure, such as you'd observed during a tectonic plate collision, those hydrocarbons turn into, you guessed it, natural gas and oil. The Arabian and Eurasian plates also contained Reservoir Rocks.

Now, this is important because Reservoir Rocks can hold oil and gas like a sponge.

ALLEN: The collision itself has created many places where these rocks are folded and these arches or domes become what's called the trap in the system. And if you cover the trap with the right kind of rock like salt, which doesn't allow fluids to pass through it, you've really completed the perfect set.

You've got everything that you need to have major accumulations of hydrocarbons of oil and gas. It was a particular set of events and conditions, all of which happened in the right order, in the right volume that have left these world class deposits of oil and gas.

CHAKRABARTI: So the collision of these two tectonic plates created the Zagros Mountains, which led to a rich deposit of oil and gas in the region.

Trapping right there what has become the most significant fossil fuel fields in the world. It also happened to create the Persian Gulf.

ALLEN: The mountain building taking place in Iran as we crumple the plates together, shorten and thicken them is loading down the Arabian plate further south, and into that space comes the seawater.

If you imagine you've got two blocks of wood or a beam of wood and a brick, you stick the brick on the end of the beam flexes, it'll go down. And that point where it's flexed down is going to be a topographic low on the surface of the earth. And in that trough, in that depression, you could flow water and it would sit there.

CHAKRABARTI: This trough is known as a fallen basin, and it collects water, in this case, water from the Arabian Sea, and that water gets from the Arabian Sea to that fallen basin today known as the Persian Gulf through a narrow passage known as the Strait of Hormuz. Now the Strait is roughly 104 miles long. More crucially, it is only 21 miles wide at its narrowest point. Iran is to the north, Oman to the south.

ALLEN: There are various reasons why mountain belts are often curved, convexed out towards their fallen that you can see them around the world, whether it's the European Alps or the Himalayas. The Zagros Mountains on the south side of Iran are no exception.

There's this beautiful crescent shape, let's just say, convex out towards the direction that the mountains are moving.

CHAKRABARTI: Now, if you've ever looked at a map of the Strait of Hormuz, you'll know what he's talking about. The southern part of the Strait kind of juts up in a sharp land finger and then the top of it at that narrow 21-mile point curves around that finger of land.

Now, while the geological story of the region is about 30 to 35 million years old, Professor Allen says the original form of the Strait of Hormuz is actually more or less what it is today because the Strait itself is not that old.

ALLEN: The Hormuz Strait's geologically a very recent feature, only a few thousand years old, very recent to a geologist.

CHAKRABARTI: That's Mark Allen. He's a professor of Earth Sciences at Durham University in England. Now, of course, a few thousand years is very recent to a geologist. Not necessarily to historians. Rudi Matthee is a professor of Middle Eastern History at the University of Delaware, and he's also the author of four prize-winning scholarly books on Iranian history, which focus on early modern Iran, between 1500 to 1800.

Professor Matthee, welcome to On Point.

RUDI MATTHEE: Thank you very much.

Happy to be here.

CHAKRABARTI: So even though oil wasn't discovered in the region until about 1908, what period of time should we be looking at to see the first sort of importance to human civilization of the Strait?

MATTHEE: That goes back to antiquity, but our information about the early period, the first millennium before the common era is very spotty and very fragmentary. And the significance of Hormuz, which is already there commercially to the extent that we know about it, really comes in much later at the end of the first millennium after the common era. So it'll be about the year 900,000 around that time, because we have written sources from that moment onwards.

That's when we got a bit of a more of a profile and especially its commercial significance becomes very important and very prominent.

CHAKRABARTI: Forgive the interruption there, I was just about to ask you and what was being traded through the Strait at that time.

MATTHEE: Mostly through time, pearls and spices.

And at some point horses from the tip of the Persian Gulf, Basra, so to speak, things of that nature. Long before oil, of course, of oil changes the entire equation, but that's 20th century.

CHAKRABARTI: Right. So in the middle of the previous millennium as you said, so around 1500 or so. Who was actually, or who were the groups, if there's more than one that were in control of the Strait.

MATTHEE: A shifting conglomeration of land powers are mostly in control. Power holders mostly on the Iranian side to which Hormuz, which is of course an island originally, was tributary. But that's a shift in a shifting consolation of powers. There's no one power holder, and it's certainly not the central Iranian power really until about 1500.

CHAKRABARTI: Okay. I'd like to actually spend a minute or two going through that shifting constellation as you said, because I understand that in the early 16th century, the Portuguese had quite a bit of influence there.

Is that correct?

MATTHEE: That's right. They landed in 1507. They retreated for a little bit, then they came back definitively in 1515.

They established a tollhouse and really made a presence for the next century plus by commandeering ships and issuing ... commercial passes that allowed them to control and to survey and to supervise shipping movements throughout the Persian Gulf.

CHAKRABARTI: That's interesting.

So we can effectively say that they were issuing, as you said, these permits or commandeering ships. Did they have total control then over the Gulf?

MATTHEE: There was, of course, never common total control because we didn't have modern surveillance methods. But they did have a very prominent and paramount presence.

And you can call this proto colonialism in a way. They were very much disliked and ultimately thrown out. But that's about a hundred years later. I mean thrown out of the Strait of Hormuz, or which is the centerpiece, really the nodal point of commerce, which had been thriving for a couple of centuries already by that time.

CHAKRABARTI: Okay. Who threw them out?

MATTHEE: We have the formation of a relatively centralized Iranian state and empire. The Safavids, they are called. They come to power in 1501. They're originated as a mystical sect. They adopt Shia Islam ... which gives them their very peculiar and particularistic identity.

They're not originally located in the south. Like most Iranian regimes, they have their antecedents in the roots in the north. They're not Central Asia, which also means they're somewhat ... averse to the sea. That's a very important theme to remember historically. ... The kind of the main ruler of that dynasty in the early 17th century expands and extends his rule and his power to the Persian Gulf.

He has a whole sort of comprehensive plan of recasting his empire, rearranging the trade line. The infrastructure and so forth towards the Persian Gulf. And with the help of the English East England Company, he manages to throw out to house to Portuguese from Hormuz in 1622.

CHAKRABARTI: Okay. This is so fascinating to me because not only do we have, as you talked about, the Safavid Dynasty, but with the earlier presence of the Portuguese and now the English getting involved, obviously European colonialism and European intra fighting between monarchies then also plays out in the Gulf region.

Well before oil was discovered in the early 1900s.

Part II

CHAKRABARTI: Professor Matthee, really appreciate the sort of brief history you gave us of from the period of 1,000 BCE to 500 or 1700 BCE, because to me it lays bare a truth that the Strait has never not been contested essentially. So what we're experiencing now is not a new phenomenon in human history, and that helps me understand better what happened in 1908, because when I often think of the discovery of oil in the Middle East, my mind first goes to Saudi Arabia, but if I understand correctly, it was in May of 1908, that oil was discovered in the southwest foothills of the Zagros Mountain, so it was in Iran. Is that correct?

MATTHEE: Yes, it is correct. It's not discovered in 1908. It's discovered already in the late 19th century. Okay? And there are, it's known that oil is existent, the need for oil and the importance in indeed essential quality of oil for modern warfare. The British changing their fleet to oil driven, for example, all accelerates the interest in oil.

So in, I think in 1901 or 1902, a concession is given to a British entrepreneur for a long-term exploration, the prospecting exploration of oil. And in 1908, we have the ... first oil gushing out of the earth, so to speak. So that's the moment when oil really becomes productive and comes online in the Iranian age.

CHAKRABARTI: I see.

MATTHEE: And it changes the entire equation. In terms of the importance of the Gulf.

CHAKRABARTI: Because it becomes the primary source of the most important energy source in the world. World War I follows soon thereafter. But you've written that at the time, obviously you've mentioned the British a couple of times, and the Russians were the biggest players in Iran, the biggest foreign players in Iran, that the U.S. was not in the picture at all.

What is the significance of the British-Russian involvement?

MATTHEE: The British-Russian involvement was one of pressure and presence in the country. Short of it making a colony.  Iran was never a colony. It was some kind of a semi protector, 1907. The British and the Russians extend their influenced by concluding an agreement whereby they divide the country into spheres of influence.

The Russians get the north, the British get the southeast, which is very interesting, because it's not where oil is found. Because for them, the ultimate import at that time, just before oil is still the strategic security of India. So the Persian Gulf is really the access route from India towards the Levant, towards the Middle East because that's not the part where oil is found, is southwest of Iran. So it comes online, just around that time. So that is a very ironic development of course, that the British sort of arrogate themselves to themselves, this arid land ... in the southeast bordering on what's today Pakistan because for them, yeah, Iran is a buffer against the Russians.

There is a neutral zone in between and that's exactly what oil is found. And then of course we gather whole tussle about access to oil, who profits for business. And it's ultimately the British, because they set up the oil industry, sort of company towns begin to because they have the monopoly for quite a while. So they really bring oil into production.

CHAKRABARTI: Okay. Just want to let listeners know that in the very near future, we're going to do a show that goes into the deep history of the middle of the 20th century regarding Iran and specifically the United States.

Because obviously this is a time at which Iran finally takes control of its own oil. Can you just quickly tell us how that happened and how the British and the Russians were pushed to the side regarding oil in the region?

MATTHEE: Yes, the Russians, of course, they have their own claims on Northern Oil.

There's also oil found in the north, in the part that they get assigned to them. But then, of course fairly quickly thereafter, it's a Russian revolution, which leads to a great deal of turmoil and the Russians temporarily retreat from Iran in terms of their interests.

And that gives free play through the British for a while. They make an agreement with Iran, impose all kinds of concessions on them in 1919. It's an agreement that's never ratified by the Iranian parliament, so it remains a bit of a moot point. And then we have a new ruler in 1921.

He's an extreme nationalist, and he really begins to reestablish Iranian control over the Persian Gulf because it's been very weak until then, the Iranians even leased part of the Persian Gulf Shore to the Sultan of Oman for almost the entire 19th century. So it's really the 20th century.

Iran has become assertive in the Persian Gulf. Then after the war, the Americans come in. They don't play a role really until then. It's in part stepping into the vacuum left by the British, who at some point in the sixties and early seventies, the retreat from the Persian Gulf, the famous retreat from east of Suez.

And into that vacuum stepped the Americans and ultimately the Iranians as well, the Shah, in other words, the one who was toppled in 1979.

CHAKRABARTI: That's actually where, when we talk about Iranian history in the near future, that's where we're going to pick up that story. But for now, Rudi Matthee, professor of Middle Eastern History and at the University of Delaware, and he's also written four prize winning books on Iranian history in the period between 1500 and 1800.

Professor Matthee, thank you so much for joining us today.

MATTHEE: You're welcome.

CHAKRABARTI: So let's get back to the actual Strait of Hormuz now that we know the geological and historical background to how the Strait became so important. Joining us now is Sal Mercogliano. He is a maritime historian at Campbell University, also an adjunct professor at the U.S. Merchant Marine Academy, and he hosts the terrific YouTube channel called “What's Going on With Shipping? Welcome back to On Point.

SAL MERCOGLIANO: Thanks for having me, Meghna.

CHAKRABARTI: All right, so I actually would love to get some shipping nerdery from you to start off with, regarding in peaceful times, what does it take to get through the Strait of Hormuz if you are an oil or natural gas super tanker.

MERCOGLIANO: I'm your person for shipping nerdery.

I've sailed through the Straits of Hormuz a few times it's an interesting passage when you go through. As you mentioned before, it's not the busiest piece of water on the planet. English Channel, the Straits of Taiwan. Those are very busy Straits. But what makes Hormuz really interesting is it is narrow.

You're always within sight of land. It's dusty, you got a lot of wind coming in, sand, it's gritty. It's never a clear day. There are fishing boats ... everywhere and you're sailing past some of the biggest oil tankers and energy vessels in the world. So it's a busy place.

Usually on average, about 135 ships are transiting in and out through the Strait of Hormuz on a given day. And Iran is always present, even when you pass the Strait and you're in the Persian Gulf. Iran is always there to the north of you and you're always cognizant of it. You can get some very interesting communications from the Iranians when you sail through.

Even during a few years ago they would communicate with you, they would harass you on the radio. It's an interesting place to sail into.

CHAKRABARTI: Harass you on the radio, like how?

MERCOGLIANO: They would call you they want to know who you are. If they knew you were an American, they may have a few choice words to say to you on the radio.

It creates a very unique environment.

CHAKRABARTI: Okay. It's about, I say this about roughly 21 miles at the narrowest point, but if I understand correctly, there's what, two actual shipping lanes there and they're each two miles wide. Is that right?

MERCOGLIANO: That's right. There's what's called a vessel traffic separation scheme.

So it's lanes like lanes on a highway. So this is to make sure that ships going inbound state to the right side. Ships heading outbound, stay to their right, to their right side. So this way you have good passage, you don't have a problem with a collision of any kind. There's some good markers as you come in there, what are called RACON buoys. So there's a good passage in there. It's well lit, navigated so that you can come in because traffic is moving all the time. There's not a slow point where there's no traffic going through the Strait of Hormuz. Except for right now.

CHAKRABARTI: Except for now. Yeah. I'm not sure if this is significant or not, but I'm just curious.

You said you could see land as you're doing the entire transit through the Strait. How far are the shipping lanes from the shore?

MERCOGLIANO: So the main shipping lane, wo when you go through the traffic separation scheme you've got Oman probably about eight miles, 10 miles to your south.

But then you have the small Iranian islands ... and some of the other islands you're always passing close to. And because of the mountains rise up so high. You see the mountains in the distance on good visibility days. But you very seldom get very good visibility in the region because of dust and haziness in that region.

CHAKRABARTI: And how long does it take, again, in peace time to get a big ship through there?

MERCOGLIANO: Oh, it's a quick passage. You're talking about maybe going through the narrowest part is maybe about 50 miles. And so you're going, about 10 to 15 knots. So just a couple hours to go through. You pilot it yourself.

You don't have to take pilotage. It's not like the Suez Canal or the Panama Canal. So you take your own, your own navigation takes you through there. And then once you get into the Persian Gulf, you follow different patterns depending where you're going. If you're going to Dubai and the UAE, you're very close by.

But if you had to have head up to the LNG facility at Qatar, that's about halfway up the Persian Gulf or the big oil terminal at Ras Tanura in Saudi Arabia. Or if you're heading all the way up to Persian Gulf, up to Basra and Kuwait, that's a bit of a longer passage. The entire Persian Gulf is about 400 nautical miles long.

CHAKRABARTI: Okay. So all of this then helps make sense as to why it's such an important passage. Because we've had questions in the past from people saying why is most of the oil that's coming out or they're coming through ships, why aren't there giant pipelines. But I guess from what you're describing, it's a relatively quick passage, right?

It's not a canal, which is really critical. So you can actually get quite a few ships through there. And then also we're talking shipping size volumes of oil or natural gas. So it seems like that it is the most, it's the fastest and most cost-effective way to get oil and LNG out of the region.

MERCOGLIANO: It is, you want to bring the ships right to where the oil and gas is and that is the easiest way. What we've seen is the development of several pipelines. The UAE has one. Saudi Arabia developed a pipeline, but unfortunately those pipelines delivered just a fraction of the oil that's needed.

About a million barrels per day through the UAE pipeline and at max probably about 5 million barrels per day through the Saudi Arabian pipeline, but that still leaves even at max capacity 14 million barrels of oil that's sitting there from Southern Iraq, Kuwait, Bahrain, Saudi Arabia, Qatar, and the UAE.

CHAKRABARTI: Okay, so I love shipping nerdery. I could spend a lot of time with you on that.

MERCOGLIANO: I do too.

CHAKRABARTI: Just random fact. What random fact that I don't know. So teach me, like for how big is a standard size oil tanker?

MERCOGLIANO: So what come in here are everything from what we would call a Suezmax tanker.

This is a tanker that's big enough to go through the Suez Canal. So we're talking about a ship and carry about 150,000 tons of oil in it, up to what are called very large crude carriers. And these are the behemoths. These are the 2 million barrels of oil. And a barrel is 42 gallons. So you start dealing with vessels well over a thousand feet long up to 200 feet wide, they're monsters. One of the interesting things that had happened back in 1968 when the Suez closed because of the six-day war and it was closed for eight years; we saw the development of these massive super tankers. What we did was build ships that were much larger, longer, wider, and deeper.

You cubed the volume of the vessel and what you get is a vessel that is much more efficient for carrying oil. So you get these behemoth ships.

CHAKRABARTI: Wow. And what's the draft on these ships?

MERCOGLIANO: Oh, the draft on these ships can run up to 50, 60 feet if they're massive enough. They're so big you can't go through the Suez Canal.

There are ships that are so large that they're actually pushing the Strait of Malacca in some ways. And some of these vessels don't even come into ports. They have to go to offshore facilities and dock, or they have to nest with other ships and conduct a ship to ship transfer to get the oil off of it.

CHAKRABARTI: Okay. So you heard professor Matthee earlier, take us through the human history, the relevant human history of the Strait. And that kind of brings us up into the 1950s where the United States starts becoming very involved in the region. I understand that, in fact, we can thank places like the Strait of Hormuz for the formation or centrality of U.S. Central Command.

Do you know that story still? Can you tell us that?

MERCOGLIANO: I do. So U.S. Navy presence has been in that region since World War II, but 1949 we stood up what was called the Middle East Force, which was a small little force that was there to monitor U.S. interests. But go back to 1979 and the Iranian revolution there was concern about what was going to happen in the Persian Gulf for obvious reasons.

There was a serious concern that the Iranians could cut the flow of the Strait of Hormuz. There was also a concern that the Soviet Union at the time could move across the Middle East and threaten the Middle East oil. So back in that period of time, the United States decided to create something called the Rapid Deployment Joint Task Force, which was really an accumulation of military units such as the 82nd Airborne, but also some afloat prepositioning ships that were loaded with equipment and stationed out in Diego Garcia, which has made the news recently out in the middle of the Indian Ocean.

And that unit, the Rapid Deployment Joint Task Force, which is a mouthful, not everyone likes saying that, decided to really coalesce into a permanent American military presence when the U.S. decided to divide the world up into military commands between Europe.

Between the Pacific Command, they decided to turn what was that unit then into central command. And that was the focus of that area. And obviously this has become the forefront of a lot of American military operations, starting with the Persian Gulf operation proceeding. That was the tanker war, the 1980s.

And we really, we've been focused on the Middle East since then, militarily.

CHAKRABARTI: The concern over the potential closure of the Strait has been front and center throughout that period of focus. Okay. You mentioned the tanker war. We've got just about a minute and a half before our next break, Sal, get us started on that. 1984.

What happened?

MERCOGLIANO: Sure. So right after the Iranian revolution, Iraq invades Iran and they get involved in a really nasty kind of land war and that land war deadlocks. And so Iraq decides to start hitting the Iranians in a way that they could. And so they start targeting their oil facilities and due to limited aircraft and their ability, they start striking at targets in the Persian Gulf.

And both Iran and Iraq will take that up. And by 1984, you're seeing tankers hit, and not just Iranian and Iraqi tankers, but other nations' tankers. And the situation escalates to the point where in 1986, Kuwait, who has a large oil presence and a tanker fleet looks for assistance, they initially went to the Soviet Union.

In an effort to not get the Soviet Union, but to entice the Americans. Because they knew the Americans would jump in at that moment, and they did. And so from 1987 to 1988, the United States led an escort operation to escort not just U.S. tankers, but Kuwaiti reflag tankers, all the way from Kuwait out through the Strait of Hormuz into the Gulf of Oman.

Part III

CHAKRABARTI: Sal before we move even closer to the present day.

Just before the break, you had said in the tanker war in 1984 that the U.S. actually sent warships to escort neutral tankers through the Strait of Hormuz. Now that's something that today, some people have called for. The president himself said countries who need the oil from the Strait should send ships to do the escorts.

People have asked, can the U.S. Navy do it? What kind of ships were escorting the tankers back in 1984? And do we in the U.S. Navy have those same types of ships today?

MERCOGLIANO: That's a great question because the U.S. Navy back then was much larger, about twice the size of what it is today, and the threats were a little bit different too.

The threat there was aircraft, it was missiles, it was bombs, and obviously one of the biggest ones was mines. And so the U.S. Navy Dispatch task forces made up of destroyers, smaller patrol vessels known as frigates, which the U.S. Navy has had a hard time building over the last 20 years and including some escort vessels, helicopter carriers, and other amphibious vessels to provide close in patrols, but you were escorting maybe about two to five tankers at a time with maybe about four to five military ships. And some threats the U.S. was well prepared for. One of the threats they were not well prepared for was mines. And one of the very first convoys, one of the tankers, the SS Bridgeton struck a mine.

The ship was able to proceed on because tankers are very large ships able to absorb the damage. The Navy was not prepared for the mine threat, and they wound up actually having to fall in behind the Bridgeton and sail behind the ship because they could not absorb a mine hit as we see later on in the conflict when a ship like the Samuel B. Roberts hits a mine, very nearly sinks.

So that created a whole new problem for the U.S. So the U.S. was able to escort limited number of vessels during that period of 1987 to '88.

CHAKRABARTI: Okay, we'll talk about the Samuel B. Roberts in just a second. But given what the U.S. Navy is like today and the types of ships they have, we also have to think about the method of attack that Iran has been using in the past four weeks.

Are the ships that the Navy could potentially send to escort vessels? It seems like they could be quite vulnerable to, as you said, things like mines, drone strikes, short range missiles. It's a real concern for the Navy.

MERCOGLIANO: It is, the U.S. Navy has probably the best air defense warship in the world, the Arleigh Burke-class destroyer.

We have over 70 of these. The problem is going to be just having enough numbers in the area, and again, the area to patrol isn't just the Strait of Hormuz. What we learned from the tanker wars, you really have to escort all the way from Kuwait down into the Gulf of Oman, almost 600 nautical miles, and that requires a lot of assets to do it.

These destroyers are very high end, about $2 billion a piece and the thread here is different. We are very good at shooting down the flock of birds, which are missiles. In that analogy, the difficulty is the swarm of gnats coming at you much smaller, bigger target, and a lot of them. And that's the big fear with these unmanned aerial and surface vessels that have struck about 20 ships so far in the Persian Gulf.

CHAKRABARTI: Okay, now you had mentioned the USS Samuel B. Roberts. Now this is from 1988, and the Roberts struck an Iranian mine, as you had said, in the Persian Gulf. So that year the U.S. Navy launched Operation Praying Mantis against Iran. And here's some archival news sound from that time. This is from the U.S. Naval Institute.

President Reagan ordered defensive action in response to the mining of USS Samuel B. Roberts. On the morning of April 18th two Iranian oil platforms, Sassan and Sirri were destroyed by naval gunfire and demolitions.

They must know that we will protect our ships and if they threaten us, they'll pay a price.

Evacuate the platform immediately. I repeat, evacuate immediately.

CHAKRABARTI: Okay, so that's from 1988. And Sal, I have to admit, I knew nothing about this and which I'm ashamed of because I understand it was the largest Navy battle since World War II?

MERCOGLIANO: That's correct. It was the largest one. It eliminated about half of the Iranian navy when all was said and done.

CHAKRABARTI: Okay. So tell me more about this.

I mean, so we actually have been in a naval engagement with Iran in this very location, some 40 years ago. It was, and as you mentioned, it had to deal with the mining of the Samuel B. Roberts and the fact that Iran decided to execute a campaign using mines. And mines are the great variable. It's the biggest, hardest weapon to deal with.

If you look post World War II, the Navy has lost more ships to mines in the post World War II era than any other weapon. And the threat of that precipitated the American response. You had both surface and aerial attacks on shipping and on these platforms throughout the Persian Gulf. The U.S. was staging aircraft carriers out in the Gulf of Oman outside the Straits of Hormuz.

So it was a concentrated effort to ensure that free passage was permitted through the Strait of Hormuz. The U.S. had gotten involved with the Kuwaitis and they wanted to make sure that free flow was going. They were also working very hand in hand at the time with the Saudi Arabians, Bahrain, and a few other nations.

And remember, this is just on the precipice of a huge American naval deployment into this region in 1990. Following the Iraqi invasion of Kuwait. So this really set up for what was going to become a full fledged permanent American naval presence, not just in the region, but in the Persian Gulf with aircraft carrier station.

Even a submarine at time was sent into the Persian Gulf and the establishment of the U.S. Fifth fleet in Bahrain. And just really the ever presence of the Americans in the Persian Gulf.

CHAKRABARTI: And so at the same time, then we have, in that same period, we have Iran repeatedly making threats to close the Strait several times.

What in 2012, 2008 those were over sanctions that were placed on Iran. The U.S. Navy even reported in 2023. So this would be in the Biden administration, that quote, since 2021, Iran has harassed, attacked, or seized nearly 20 internationally flagged merchant vessels, presenting a clear threat to regional maritime security and the global economy.

So there's a lot of like mutual tension here for a more than a decade in the Strait. But I want to just stick with mines for another second because that takes us back to a question that one of our listeners had near the top. Clearly the Strait has been mined before. Are their minds there now, Sal? And if so, doesn't that also present a threat to Iranian vessels?

MERCOGLIANO: There is no positive indication of mines. The latest report that came out from the Joint Maritime Information Center has the basically no mines have been laid, but I should note that it takes exactly zero mines to create a minefield. It's just the threat of mines creates that danger. I always go back to the great press conference General Schwarzkopf  gave during the Desert Storm when he talked about what a minefield is. You don't need a mine to do that, but mines come in different shapes and different forms too, and that's why they're so dangerous. You have the kind of traditional big ball with a horn on it that's floating in the water.

That's actually the least dangerous type. Because you can see that. You can identify it. It's the ones that are anchored to the bottom, below the surface, that are very difficult to find and even more dangerous are what are called bottom mines. These are mines that are sitting on the bottom of the ocean, metal, or even plastic containers.

They can be set up so that they don't detonate when the first ship comes over. Or they could be set up to detonate when they detect a certain magnetic influence or acoustics. And what they do is they create a huge explosion in the water, an air bubble that comes up and literally lifts a ship up, drops it, and breaks its back.

And that could be catastrophic for a warship or even a commercial ship, even a super tanker.

CHAKRABARTI: Wow. I'm thinking of the visual of a thousand-foot tanker being blown upwards and flipped over by the force of an underwater explosion. It's truly something. Okay but you just explained why, in fact, if there are mines there and it seems like Iran could actually control the risk to its own ships from what you described.

Is that fair?

MERCOGLIANO: They could and they would also know where they laid it. So even though we're talking about a narrow waterway, 21 miles, it's still a wide area. So you can mine, for example, usually, the highly trafficked, those two-mile lanes, you can mine those. But the areas, for example, along the coastal side of Iran, because you can actually sail into the Strait of Hormuz through just the entire coastline within the 12 miles of Iran without any difficulty at all.

So the Iranians don't have to mine that, but that would be within Iranian national waters.

CHAKRABARTI: Okay. So since there has been, there has been military action, there's been decades of tension there, but we've never had the full closure of the Strait of Hormuz until this month. So let's just take a moment to listen to members of the Trump administration and how they've talked about this, because the truth is for quite a while, the Trump administration has been downplaying the significance of the massive shipping disruptions through the Strait.

For example, here's Secretary of Defense Pete Hegseth on March 13th.

PETE HEGSETH: And as the world is seeing, they are exercising sheer desperation in the Straits of Hormuz. It's something we're dealing with. We have been dealing with it and don't need to worry about it.

CHAKRABARTI: Markets definitely disagreed with the secretary.

Here's President Trump on March 20th. Just outside the White House.

DONALD TRUMP: We're doing very well overall. We don't use the Strait, we don't, the United States. We don't need it. Europe needs it, Korea, Japan, China, a lot of other people, so they'll have to get involved a little bit on that one.

CHAKRABARTI: On Friday, the United States Treasury lifted sanctions on Iranian oil that is already stored in tankers at sea. And some estimates show that would allow to get some $14 billion in oil revenue. And by the way, this would be the first time the sanctions have been lifted since the late 1990s. On Sunday, treasury Secretary Scott Bessent was asked on Meet the Press by Kristen Welker, why the U.S. was helping to fund a country that is currently at war with, and here's the secretary.

That Iranian oil was always going to be sold to the Chinese. It was going to be sold at a discount. So which is better, if oil prices spiked to $150 and they were getting 70% of that, or oil prices below a hundred, it's better to have them where they are now. And to be clear, we had always planned for this contingency. About 140 million barrels are out on the water. In essence, we are jiu jitsuing the Iranians. We are using their own oil against them.

CHAKRABARTI: Sal, I gotta ask you, do you see this as brilliant jiujitsu by the Trump administration right now?

MERCOGLIANO: I don't. I see this as an effort by the Trump administration to try to control the ever-escalating cost of gasoline and diesel fuel in the United States. Because while the Trump administration has executed a military campaign to decapitate the Iranian military and leadership, what they don't have is a plan to open up the Strait of Hormuz.

And while that may be a factor they already planned on, I don't think they quite planned on the chaos this is causing across global markets, and that's what we're seeing when you pinch off 20% of global oil, that has an impact across the board. And even though we may import a very little amount out of there, it has a massive impact.

Just for example, bunker fuel, the fuel we use to fuel ships has jumped from $450 a ton to over $900. So that means everything that moves on the ocean today is more expensive to move. And now with this reduction in oil coming out of the Persian Gulf, what Secretary Bessent was talking about is we're draining the available stocks, even the Iranian and Russian oil, but there's going to be a point where that excess stock, which is floating out on the ocean, is going to be depleted.

That's why we see the release of the strategic petroleum reserves, but eventually we're going to catch up to the fact that we're missing about 20% of global oil and when that hits, that's going to be the major problem in a few weeks.

CHAKRABARTI: Okay last question or two I have for you, Sal. You said that even just the possibility of a mine is enough to basically make insurers, shippers not want to transit through the Strait.

I feel like we've passed, we've crossed a Rubicon here because even though Iran had threatened to close the Strait for many years, they've actually done it this time, which makes me wonder if those same insurance and shipping companies will ever see the Strait of Hormuz as a low risk transit anymore.

This sounds like it might have permanently changed shipping in the region.

MERCOGLIANO: Meghna, we saw this in the eighties when all of a sudden Iran and Iraq went to war. What we saw was war risk insurance. The insurance you have to pay to sail a ship into a highly contentious area. That's the additional premium you pay.

Went up. It went up to about, from a fraction of a percent to one, to three, to five, and in some cases 10%. And the tanker war, we saw 411 ships get hit, 55 of them were lost. Several hundred merchant mariners were killed. What stopped the ships from going in and out of the Persian Gulf initially in this event was the war risk insurance. But once war risk insurance was in place, which took about a week, once that was in place, what the shipping companies and what the Mariners are looking for now is some sign of security, either by the United States or other nations around the world. And unfortunately, what they're seeing right now is Iran is basically offering passage through the Strait of Hormuz, but at a price.

CHAKRABARTI: You gotta pay, exactly. Some several million dollars as I've seen reported. Okay. So I just have one last quick question for you, and we've got about 40 seconds here. You mentioned the merchant mariners. There are so many of them stuck on their ships still right now. There's a humanitarian crisis going on there, right?

What have you heard?

MERCOGLIANO: There is. We're talking about somewhere in the range of 3,200 ships, 20,000 mariners. Ships are meant to be moving. They're always meant to be moving from place to place. Crews on board, large super tankers. The biggest vessels in the world are maybe 20, 25 people, and they don't have enough food and stores really for protracted periods of time.

When they come into port, they plan on reloading and going out. They have limited fuel on board. If the ships aren't moving, they can't produce water. So we're seeing a humanitarian crisis here, plus these are civilians. They're caught in the middle. We know of at least eight Mariners who've been killed, maybe as many as 11 and some are taking up the banner that they're a new yellow fleet.

This was the fleet that got caught in the Suez in 1968 and was trapped for eight years. So they're worried about being trapped in the Persian Gulf.

The first draft of this transcript was created by Descript, an AI transcription tool. An On Point producer then thoroughly reviewed, corrected, and reformatted the transcript before publication. The use of this AI tool creates the capacity to provide these transcripts.