The Houthi Campaign in the Red Sea: An Analysis and Look Ahead
Key Findings
Since 19th November 2023, the Yemen-based Houthi group has been conducting a campaign of mainly missile and drone strikes against commercial shipping in the Bab-al-Mandeb Strait, one of the Middle East’s two major chokepoints.
While economically damaging, the campaign has not, hitherto, been particularly heavyweight, and most attacks have caused little damage and no reported casualties.
An international coalition has responded with Operation Prosperity Guardian and very limited air strikes but it does not appear to be particularly robust and the Houthis retain the intent and capability to maintain their campaign.
While there appears to be little appetite for escalation in Iran – or Western capitals – history shows that Tehran has considerable experience of asymmetric naval operations and could up the ante considerably in regional waters via the Houthis if it so chose, with sea mines a possible threat.
The prospect of accidental escalation remains real, with the US and Iran both having previously downed civilian passenger aircraft by mistake at times of heightened tension in the region.
Background
Immediately following the Hamas’ incursion into Israel on 7th October 2023, the latter’s northern border with Lebanon became the focal point for concerns that the conflict would escalate into a wider regional war between Tel Aviv and Iranian proxy militia groups if not Iran itself. So far, Iran’s proxy agent in Lebanon, Hezbollah, has shown little appetite for much more than daily tit-for-tat exchanges of fire with Israel Defence Force (IDF) units in the north of the country. That is despite Israel’s assassination of the Hamas political bureau deputy in Beirut on 2nd January 2024, possibly the day before he was due to meet Hezbollah’s Secretary General, Hassan Nasrallah.
Instead, one of the centres of gravity of what has been a gradual but undisputable escalation of violence across the region has emerged well over 2000 km to the south, in the Red Sea, the Bab-al-Mandeb Strait, and the Gulf of Aden. Since 19th November, there have been at least 33 attacks against commercial and military vessels transiting international shipping lanes in these waters. The majority have reportedly been conducted by the Houthis – also known as Ansar Allah – another Shi’a Iranian proxy group which dominates Yemen’s Red Sea coast. The three main tactics used thus far have been anti-ship cruise missile strikes (16) either combined with or separate from drone strikes (at least five) and attempted boardings (four). Of the projectiles fired, 10 have struck home, causing mainly minor damage and no reported casualties.
The fallout from the first strikes was almost immediate; a number of prominent international carriers – not least Maersk, Hapag-Lloyd, CMA CGM, MSC, and Evergreen – placed the Red Sea temporarily out of bounds, some of them diverting their ships around the Cape of Good Hope. Even if the companies themselves have a risk appetite, their insurers certainly do not, with premiums having shown an initial increase from 0.7% of the value of a ship to 1.0% in the second week of January 2024. In the meantime, with around 40% of Asia-Europe maritime trade transiting the Red Sea north to the Suez Canal, costs of fuel have surged as ships now take an extra ten days on average to reach Western European waters from southeast Asia. Increased prices and delays to international supply chains are hitting home particularly hard just as the World recovers from the Pandemic.
A Glance Back into History
Of seven major maritime chokepoints across the planet, two of them – the Bab-al-Mandeb Strait and the Straits of Hormuz – are in the Middle East to the east and west of the Arabian Peninsula. Blockading or attacking shipping passing through such narrow waterways has never been particularly difficult for hostile actors controlling the sea lanes themselves or the nearby coastlines. It is no coincidence that the UK continues to refuse to relinquish its control of the Straits of Gibraltar to Spain.
The current Houthi attacks and their possible future evolution may be better understood in a historical framework, an obvious comparison being the so-called “Tanker War” just over three decades ago. This maritime campaign ebbed and flowed across the Persian Gulf for much of the Iran-Iraq War (1980-1988) as the two countries vied to cut each other’s supply lines by conducting attacks against commercial shipping at a rate not seen since the Second World War.
Between 1981 and 1987, the two combatants attacked well more than 350 vessels flagged to 39 different countries between the northern Persian Gulf and the 33 km wide Straits of Hormuz to the south. Of these, approximately 75% were oil or chemical tankers and 15% were container ships. Of the oil tankers struck, about 23% were sunk or assessed to be Constructive Total Loss (CTL) or, in layman’s terms, beyond repair. The same figure for container vessels was 39%. The human losses were at least 116 dead and 167 wounded.
By 1987, the campaign had threatened to close the Straits of Hormuz, prompting a military intervention by the US. Operation Earnest Will ran from July 1987 to September 1988 to protect Kuwaiti vessels, many of which were re-flagged to the United States. That was the largest convoy-protection operation since the days of the Battle of the Atlantic in the Second World War. In April 1988, Earnest Will gave rise to Operation Praying Mantis when a US convoy protection vessel sustained significant damage after hitting an Iranian mine. In the days that followed, the Americans destroyed three of Tehran’s battleships and two of its oil platforms, largely putting an end to the Tanker War.
Fast Forward to The Red Sea, 2023
There are notable differences between current events in the Red Sea and what occurred in the Persian Gulf more than thirty years ago. First and foremost, the Tanker War was part of a much wider, conventional conflict involving two national militaries; both had far greater capability and freedom of movement compared to the non-state Houthis. Iran’s military support of the latter indicates that, currently, the group is highly unlikely to be able to inflict losses on commercial shipping in the Red Sea comparable to those of the Tanker War.
Before the events of 7th October further north in the Levant, the Houthis were known to be a part of Iran’s web of proxies across the Middle East but they were not considered to be a particularly high threat. Indeed, the US State Department lifted the group’s designation as a terrorist group in 2021 before reimposing it in January 2024 following its burgeoning campaign of violence in the southern Red Sea. It is through this campaign that some useful comparisons with the Tanker War can be made and some inferences as to its possible future direction made.
Ziba Kenar – The Khameini Academy of Naval Sciences and Technology
Iran was at something of a disadvantage during the Tanker War, particularly in its early years when it lagged far behind Baghdad in terms of anti-ship missile capabilities. Indeed, it often resorted to asymmetric tactics, famously employing swarms of fast speedboats to overwhelm targets (much like drone tactics today) and repurposing projectiles designed to knock out armoured vehicles to attack vessels. According to Martin S. Navias of the Department of War Studies, King’s College London, following the war, Iran “invested heavily in a range of anti-shipping capabilities including, small submarines, mines, anti-shipping weaponry and large numbers of fast attack boats geared towards swarming tactics”.
Today, Tehran has two major naval forces – the regular Islamic Republic of Iran Navy (IRIN) and the Navy of the Islamic Revolutionary Guard Corps (NEDSA or ‘The Sepah Navy’). The Islamic Revolutionary Guard Corps (IRGC) is entrusted with protecting the Iranian state from outside interference and is known to propagate the country’s military and ideological influence across the Middle East and further afield. Given its external responsibilities, it is NEDSA that now projects Iranian power into the region’s waters, both the Persian Gulf and The Red Sea, using tactics largely honed during the Tanker War.
In the second week of January 2024, the UK’s Daily Telegraph led a story of the existence of a secretive NEDSA training academy at Ziba Kenar, which is rather euphemistically named “The Khameini Academy of Naval Sciences and Technology”. Sitting on the southern shores of the Caspian Sea 230 km northwest of Tehran, this base is said to have been established in 2013 to standardise all IRGC naval training, including that of proxy groups. Its recent intakes have, anecdotally, included a cohort of 200 Houthi fighters. They have no doubt benefited from the Iranian experience earned in the Tanker War.
Could the Attacks Spread?
So, what can be inferred about current Houthi capabilities and any future evolution of its campaign in the Red Sea? First and foremost, the group is operating with the full sponsorship of masters in Tehran. This is a strategic no-brainer for the IRGC as regional tensions increase; it already controlled the entire east coast of the Persian Gulf and, with the Houthis now on its books, it can exert at least a modicum of sea-denial over the Bab-al-Mandeb Strait. In other words, it has the potential to disrupt commercial activity along both of the Middle East’s maritime chokepoints.
Around 20% of the world’s petroleum passes through the Straits of Hormuz, equating to around $1.2 billion a day. Whether or not the Red Sea campaign would be emulated there remains to be seen but historic precedent suggests this is a realistic possibility as friction ratchets up across the region. Notwithstanding, at the moment, the appetite for major escalation across the Middle East seems weak. As already discussed, Hezbollah has not realised fears from late last year that it would try to draw Israel into a second front in the Levant.
More recently, international anxiety mounted again when the Iranians conducted a ballistic missile attack against Pakistan, just on the other side of its southeastern frontier. Causing less than a handful of casualties, it appears to have been a tokenistic retaliation against a local Sunni terrorist group called Ja’ish al-Adl. It is purported to have facilitated twin blasts that killed 84 at a memorial for the late head of the IRGC – General Qassem Soleimani – in the southeast of the country in early January.
The Pakistani response was an equally innocuous missile strike a few days later. Indeed, at the time of writing, the two countries had restored full diplomatic relations. So, for the moment, there does not appear to be any appetite for escalation in the Middle East and so any spread of attacks against shipping in the Persian Gulf seems unlikely as things stand.
Houthi Capability and Intent – an Analysis
Despite the reaction of the likes of Maersk, Hapag-Lloyd, CMA CGM, MSC, Evergreen and maritime insures, the Houthi campaign should be regarded with a clear head. No, it is not good news but, so far, just about all of the ships targeted have sustained minor damage and have been able to get back underway fairly quickly with no casualties reported. Even if 200 Houthis are recent alumni of The Khameini Academy of Naval Sciences and Technology, their attacks have not been that effective in terms of the level of damage or casualties reported.
Although it has been reported that an Iranian spy ship named “The Behshad” has been lurking around the Gulf of Aden disguised as a freighter for several months, passing targeting information to the Houthis, only nine of 28 (32%) attacks using projectiles have struck their targets. It can, therefore, be assumed that their Intelligence, Surveillance and Reconnaissance (ISR) capability is limited. If they are using modern anti-ship missiles and drones, their strike rate should be higher. With this in mind, any comparisons to the Atlantic Convoys of World War Two are unhelpful at best.
Moreover, it may be that the Houthis are under orders from their Iranian masters to show some restraint. An apparent lack of appetite for escalation has already been discussed, but Tehran may also fear alienation from other regional actors if the attacks become too damaging to international shipping. Since the inception of the Houthi campaign, Egypt has lost around 40% of its usual revenues from ships transiting the Suez Canal. Jordan’s Aqaba also sits atop the Red Sea and, thus far, there has been a reported 16% decrease in cargo transiting its only port, since November 2023. It is also likely that Saudi Arabia’s Red Sea port of Jeddah has suffered similar losses. Perhaps the Houthi campaign is partially intended to give the group some leverage during peace talks with the Saudis, but they cannot push the boundaries too far.
However, any cause for optimism must be placed in a historical context. On 3rd August 2021, as tensions between Washington and Iran peaked once again, what were widely held to have been IRGC commandos temporarily boarded the asphalt tanker, Asphalt Princess, in the Gulf of Oman. There were no casualties and the attackers decamped upon the arrival of Omani and US Navy assets. Just one month earlier, the oil tanker MT Mercer Street had been attacked near the Omani island of Masirah in the Persian Gulf. Two – possibly three – separate strikes attributed to drones over 48 hours killed two people and tore a 6 ft hole in the pilot’s house. Almost certainly the work of NEDSA, this incident followed a spate of attacks in 2019. In May that year, three tankers and a bunkering ship sustained 5 to 10 ft breaches near or just below the waterline by what an international investigation assessed to have been limpet mines attached to the hulls by operatives in fast boats. Just a month later, two more tankers were set alight by mines or drones in the Straits of Hormuz.
Needless to say, all of these attacks were rather more sophisticated and effective than most of those seen thus far in the Red Sea. That was probably because they were conducted by the better-trained and equipped IRGC schooled in tactics learned during the Tanker War. What is more, they took place much nearer Iran, where those responsible would have enjoyed greater freedom of movement, top cover from friendly assets, and shorter supply lines than in the Red Sea. The key takeaway from this is that the Iranians do have the capability to conduct more effective attacks than those recently attributed to the Houthis.
Nor should the capability of the Houthis be underestimated, particularly if they were to be better-resourced by Iran in the future and further benefit from the IRGC’s tactical experience from the Tanker War. Their recent history of fighting the civil war in Yemen – and resisting unrelenting Saudi intervention – has shown them to be a hardy, determined group. Their ethos is best summed up by their famous slogan – "God Is the Greatest, Death to America, Death to Israel, A Curse Upon the Jews, Victory to Islam".
Their Red Sea campaign was inaugurated, on 19th November 2023, by a very slick commando-style operation in which a group of fighters was filmed being delivered aboard the massive car transporter, the Galaxy Leader, by helicopter before hijacking the vessel and taking it back to Yemeni waters. It is now something of a tourist attraction in the port of Hudeidah and its crew of 25 is still being held hostage. This operation probably gave a foretaste of the group’s potential if it was to be better armed in the future.
The use of sea mines deserves a mention as well. As described above, Operation Praying Mantis in 1988 was the US military response to its escort vessel, the USS Samuel B Roberts, hitting one of Tehran’s stray mines while on convoy protection duties in the Persian Gulf. Shortly after, direct surface naval combat ensued between Iran and the US Navy. Since the early days of the Tanker War, Iran has favoured sea mines for their relative ease of use and impressive value. More modern models are also difficult to detect and time-consuming to clear. Although not reported so far, they have been sown extensively in the Persian Gulf over the years and it is not inconceivable that they could be used to intimidate and harass indiscriminately in the Red Sea if the situation were to escalate.
The Western Response
The US-led response to the Houthi attacks in the Red Sea has been one of containment and minimal escalation. Operation Prosperity Guardian is a naval policing operation involving more than 20 countries set up in December 2023 to protect local commercial shipping. The effort’s very name seems intended to emphasise its economic rather than military bent as the West – like many of the Middle East’s leading actors – seeks to avoid any ramping up of tempers.
In tandem, since 11th January, the US and UK have conducted a series of eight limited air strikes intended to degrade Houthi drone and anti-ship missile capability. The extent to which these have been successful is unclear, although the portability of the weapons systems involved – particularly drones – probably makes them difficult targets to locate. At the time of writing, there were some signs of damage to the Houthis; between the 11th and 21st of January, there were just five attempted strikes – one successful – compared to three or four on three single days in December 2023 (3rd, 15th and 23rd).
Behind the scenes, the air campaign is, arguably being complemented by covert special forces operations. The US and UK both have a tried and tested capability in this field and two US Navy SEALs probably reported missing somewhere off the coast of Somalia on 11th January were engaged in some sort of maritime operation to interdict Iranian missile parts en route from east Africa to Yemen. Needless to say, reporting around any such effort is sparse.
Nonetheless, while they might have suffered some physical damage, the Houthis are psychologically unbowed, offering a characteristically robust and defiant response to the international coalition. In a statement as recently as 18th January, the group’s leader, Abdul Malik al-Houthi, asserted: “The American and British aggression will only contribute to us developing our military capabilities”. It can only be hoped that these final words are not indicative of an impending increase in Iranian support. As discussed above, this could cause problems.
Looking Ahead
It is very likely that Houthi attacks will continue. Indeed, one of their more serious attacks was reported on the evening of 26th January when a missile hit an oil tanker causing a blaze in one of its petroleum cargo tanks. The Marlin Luanda is registered to a British company, so possibly, it was deliberately singled out as a target in retaliation for the UK’s role in recent airstrikes against Houthi targets in Yemen. While the fire took 19 hours to bring under control, no casualties were reported.
Aside from any damage inflicted by these airstrikes, the Houthis have probably been emboldened by some conspicuous cracks in the international coalition around Prosperity Guardian and the recent air attacks. Ten of the 20 partners have chosen to remain anonymous, and there are some notable European and regional absentees, reflecting the divisive nature of the Israel-Hamas war and fears of a wider conflagration.
Furthermore, it will not be lost on the Houthis that Prosperity Guardian has caused some embarrassment in the UK, given the Royal Navy’s failure to commit either of its new state-of-the-art aircraft carriers to the region due to apparent manpower shortages. They will also be aware that they are scoring an economic victory every time a Western combat vessel intercepts one of their drones. A Shahed-136 drone costs approximately $20,000 while a single British Sea Viper surface-to-air missile sent up to knock it out comes in at between one and two million dollars. This is very likely to embolden the Houthis, who are most keen to establish themselves as regional actors capable of taking on the likes of Israel and the US.
With regular disputes currently erupting across the region – many involving Iranian franchises – history also tells us that there is a realistic possibility of unintended escalation in the Red Sea or Persian Gulf. It would not be the first time that very serious mistakes have been made thereabouts. On 3rd July 1988, following Operation Praying Mantis, tensions were high enough between the US and Iran for the guided missile destroyer, the USS Vincennes, to mistakenly shoot down an Iranian Air Airbus A300, killing all 290 onboard directly over the Straits of Hormuz. Given the size of the aircraft, radar operators onboard the Vincennes had wrongly identified it as an F-14 Tomcat. More recently, in January 2020, the Iranians misidentified a Ukraine International Airlines Boeing 737-800 as an incoming American cruise missile, bringing it down near Imam Khomeini International Airport, Tehran, with the loss of 176 passengers and crew.
Still, the current situation indicates that there is no appetite for intentional escalation in the Middle East. Afghanistan and Iraq still hang heavily over the US and the UK. Iran is certainly showing no signs of any inclination for a broader conflict while being probably too focused on further progressing its nuclear development program and quelling internal dissent. Particularly telling was Tehran’s military response to the 31st December 2023 sinking of three Houthi gunboats by a US attack helicopter near the Bab-al-Mandeb Strait. The sum total of its support for its proxy was to deploy – very briefly – the Alborz, an aged frigate launched in 1969 and gifted to the Shah of Iran by the UK. That was hardly the retaliation of a country looking for a fight.