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Five vessels, no AIS: Hormuz goes dark

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20:34UTC

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

International human rights monitors (NetBlocks, IHR, Hengaw)

NetBlocks recorded 1,704 cumulative hours of near-total internet blackout for roughly 90 million Iranians on Day 74, while IHR documented ongoing executions under emergency provisions. These organisations are the only active monitoring windows into a civilian population cut off from the global internet for 71 consecutive days.

UK / France coalition

The Royal Navy confirmed HMS Dragon's Hormuz deployment on its own website on 11 May, converting a press-reported presence into declared force posture; UK and French defence ministers hosted a coalition meeting the same day. Britain and France are now the only named contributors to a Hormuz escort mission all five allies Trump originally asked had declined.

Saudi Aramco / Gulf producers

Saudi Aramco CEO Amin Nasser warned on 11 May that a Hormuz closure could remove 100 million barrels of weekly supply from global markets (roughly 15 million barrels per day for a week), a figure that dwarfs any OPEC+ swing capacity. The warning functions as both a price-floor signal and a public pressure on Washington to protect transit.

Beijing / Chinese Government

China has not publicly acknowledged the four Hong Kong-registered entities designated on 11 May or extended MOFCOM's Blocking Rules cover to HK-domiciled firms. Xi Jinping hosts Trump on 14–15 May having already de-risked state-bank balance sheets via NFRA's quiet loan halt, entering the summit partially compliant before any negotiation.

Tehran / Iranian Government

Foreign Minister Araghchi described Iran's 10-point counter-proposal as 'reasonable and responsible' via spokesman Baqaei on 11 May, and widened the mediator pool by meeting Turkish, Egyptian, and Dutch counterparts in a single day. Tehran is buying procedural runway while Trump's verbal rejection went unmatched by any written US counter.

Trump White House

Trump called the ceasefire 'on massive life support' and dismissed Iran's 10-point counter-proposal as 'a piece of garbage' on 11 May, while departing for Beijing two days later with no signed Iran instrument to show Congress. The verbal maximum and the paper void coexist: the administration is running a legal pressure campaign through Treasury while the president free-lances the rhetoric.