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Five vessels, no AIS: Hormuz goes dark

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11:11UTC

All five vessels that transited the Strait of Hormuz on Thursday 23 April had AIS suppressed, the blockade's first fully dark crossing day, Lloyd's List confirmed.

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Key takeaway

P&I withdrawal has emptied Hormuz of legal traffic; no JWC redesignation is on the underwriting calendar.

All five vessels that transited the Strait of Hormuz on Thursday 23 April were running with their Automatic Identification System (AIS) suppressed, the first day of zero AIS-visible crossings since the blockade began, Lloyd's List confirmed ¹. AIS is the maritime safety beacon required by the International Maritime Organisation that broadcasts a vessel's identity, position and heading; suppressing it is a deliberate act, normally penalised by port-state controls. Lloyd's List is the trade journal of the global shipping industry and the first-resort source for war-risk insurance pricing.

The cause sits in the London insurance market rather than the Iranian gunline. The five major Protection and Indemnity (P&I) clubs (Gard, Skuld, NorthStandard, London P&I and the American Club) cancelled war-risk cover for Iranian waters from around 5 March 2026. The London Joint War Committee (JWC), the underwriting body that designates global war-risk zones, expanded its zone to include Bahrain, Kuwait, Oman, Qatar and Djibouti; war-risk premiums have risen tenfold to what Lloyd's List describes as "double-digit millions per trip". An insured vessel that loses its P&I cover loses port-of-call access, charterer indemnities and the ability to transit a Suez or Panama queue without underwriter sign-off.

Insured tonnage has therefore stopped trying. The only ships still moving through Hormuz are sanctioned dark-fleet hulls operating outside legal insurance frameworks , which is the population CENTCOM's 33-vessel intercept count is being measured against. Both numbers describe a strait that has self-organised to be invisible. For European, Korean, Japanese and Indian flag tonnage, the strait of Hormuz is closed in commercial terms until either the JWC redesignates the war zone or the P&I clubs reinstate cover, neither of which is on the underwriting calendar.

The 5 March P&I withdrawal was a private commercial decision that has functioned as a more durable blockade than CENTCOM's enforcement. War-risk underwriting, not naval power, has emptied the chokepoint.

Deep Analysis

In plain English

When ships carry cargo across the world's oceans, their owners pay insurance to cover damage or loss. The companies that provide this insurance, called P&I clubs, cancelled their coverage for ships going through the Strait of Hormuz in early March. Without insurance, shipping companies cannot get permission to use major international ports, cannot get cargo contracts from big oil companies, and cannot get financing from banks. So even if there were no navy ships trying to stop them, commercial tankers and cargo ships cannot legally or financially complete a Hormuz transit. The ships that are still going through are the 'dark fleet' vessels that never had legitimate insurance to begin with, operating outside the normal rules of international shipping.

Deep Analysis

Root Causes

P&I clubs operate as mutual insurers: their reserves are funded by member premiums, not external capital. A single total-loss event in the JWC war zone would trigger reinsurance calls on Lloyd's syndicates that are themselves capitalised to handle a pre-war risk distribution, not a wartime total-loss scenario. The clubs' March 2026 withdrawal was a capital-adequacy response: their reinsurance treaties required them to exit a war zone once designated.

The **JWC**'s designation of Bahrain, Kuwait, Oman, Qatar and Djibouti alongside the existing Iranian-waters designation created an unprecedented contiguous war-zone footprint. Under standard reinsurance terms, continued cover across that footprint became untenable, forcing even clubs that might have negotiated individual endorsements to exit the entire zone simultaneously.

What could happen next?

Meaning
If a VLCC is lost in the JWC war zone, the reinsurance call on Lloyd's syndicates could exhaust the reserves of multiple P&I clubs simultaneously, triggering a global shipping-insurance liquidity crisis that would extend the commercial closure of Hormuz well beyond the end of any military engagement.
Short term · Assessed
Meaning
The JWC's expanded war-zone designation covering five additional Gulf states means European, Korean and Japanese flag tonnage cannot transit the entire Gulf region without war-risk endorsements, effectively closing the Gulf to insured shipping rather than just Hormuz.
Short term · Assessed
Meaning
A redesignation of the JWC war zone is the most commercially impactful single policy action available; it requires the JWC to judge that the military risk has reduced, a judgment that cannot be made while three US carrier strike groups are in theatre with no signed rules of engagement.
Short term · Assessed

Source Landscape

This story draws on neutral-leaning sources from United Kingdom

United Kingdom

Primary parallel: The 1984-1988 Tanker War, when Iraq and Iran attacked each other's oil shipping in the Persian Gulf, produced a similar insurance-market response. Lloyd's of London syndicates raised Gulf war-risk premiums by 600% over the first 12 months; the UK, US, French, Belgian, Italian and Dutch navies ultimately deployed to protect reflagged tankers.

The 2026 situation has diverged at the critical point: in 1984-88, Western navies arrived alongside Lloyd's rate increases to maintain some commercial traffic. In 2026, Lloyd's has cancelled cover entirely and CENTCOM is conducting an active blockade rather than an escort mission.

Counter-parallel: The 2019 Gulf of Oman tanker attacks prompted JWC to designate The Gulf as a war zone for roughly six weeks before redesignating it as the attacks subsided. That precedent suggests JWC designation is revisable; the difference in 2026 is that the attacks in 2019 were sporadic, not a sustained military blockade backed by three US carrier strike groups.

Consensus view: NorthStandard, one of the five P&I clubs that cancelled Iranian-waters cover, has internally estimated that a sustained blockade of more than 90 days will produce structural P&I insolvency risk if a single Suezmax or VLCC is lost in the war zone; current reserves are sized for a pattern of collisions and machinery failures, not wartime total loss.

The London P&I Club's published war-risk policy language excludes losses in the JWC (Joint War Committee) designated war zone without a separately negotiated war-risk endorsement; at premiums that Lloyd's List puts in the tens of millions per voyage, no commercial operator has found that endorsement commercially viable.

Counter-view: IUMI (International Union of Marine Insurance) secretary general Lars Lange argued in April 2026 that the P&I withdrawal has created a two-tier strait: dark-fleet operators with no legitimate P&I cover are now the only active transiting population, meaning the underwriting market has handed enforcement of Hormuz to CENTCOM by default, not by design. The clubs did not coordinate with CENTCOM; the commercial and naval effects have converged accidentally.

Key tension: Whether the JWC can redesignate the Hormuz war zone before P&I capital reserves are stressed by a major hull loss, or whether the first VLCC total-loss event forces a systemic reinsurance crisis that further freezes the strait.

First Reported In

Update #80 · Three carriers, zero instruments

Lloyd's List· 26 Apr 2026

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Causes and effects

Caused by

Seven VLCCs at Chabahar, three at Hormuz

The all-dark AIS transit day on 23 April advances the dark-fleet dominance pattern documented by Windward on 19-20 April (ID:2671), where only 3 transits were recorded and 7 VLCCs were held near Chabahar.

Occurred 20 Apr 2026

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This Event

Five vessels, no AIS: Hormuz goes dark

The London insurance market, not the Iranian gunline, has now emptied the Strait of Hormuz of legal traffic.

Different Perspectives

Israel

Israeli strikes on Hezbollah positions in Lebanon continued through the weekend, maintaining the secondary front. The IDF has publicly named Mojtaba Khamenei as an assassination target; his courier-governance mode complicates targeting but does not remove him from the order.

Russia

Putin told a Moscow press conference that Washington, not Tehran or Moscow, killed the Russia-custody uranium arrangement by demanding US-territory-only storage. Neither Tehran nor Washington has corroborated the account, which appeared in second-tier outlets only, consistent with a trial balloon rather than a formal position.

United Kingdom

HMS Dragon was redeployed from the Eastern Mediterranean to the Middle East on 9 May, the first physical European platform commitment to the Gulf. The Ministry of Defence called it "prudent planning" while publishing no rules of engagement, no tasking order, and no vessel name, committing a named asset to a conflict zone before the political instrument authorising it exists.

United Arab Emirates

UAE air defences intercepted two Iranian drones over its territory on 10 May, a kinetic escalation six days after the Fujairah oil terminal strike that drew no formal protest. The three-state simultaneous operation, not the severity of individual strikes, appears to have crossed the threshold at which the GCC states collectively began responding.

Saudi Arabia

Riyadh issued the first formal Gulf-state protest of the conflict on 10 May, demanding an "immediate halt to blatant attacks on territories and territorial waters of Gulf states", ending 10 weeks of channelling displeasure through OPEC+ quota discussions. The protest forecloses Saudi Arabia's preferred quiet-channel role and reduces the functioning back-channel architecture to Pakistan alone.

Qatar

Doha is simultaneously a strike target, the site of the Safesea Neha attack 23 nautical miles offshore, and an active MOU mediator: Qatar's prime minister met Rubio and Vance in Washington the same weekend. Whether Qatar issues its own formal protest or maintains its dual role is the critical escalation indicator for the week of 11 May.