16MAY

GPS blacked out across Gulf chokepoints

2 min read

12:41UTC

US and British maritime authorities confirm an electronic warfare corridor stretching 2,500 kilometres across two of the world's three critical sea lanes. There is no safe detour.

← Back to Two Hormuz papers; Washington on neither Jump to analysis ↓

ConflictDeveloping

Key takeaway

An electronic warfare corridor now links two chokepoints, leaving no safe maritime alternative.

MARAD Advisory 2026-004 and UKMTO data confirm severe GNSS/GPS interference extending from the strait of Hormuz across The Gulf of Oman and into the Red Sea near Bab al-Mandeb ¹. This is not a side effect of military operations but a deliberate electronic denial zone spanning two of the world's three critical maritime chokepoints.

No modern peacetime precedent exists for electronic warfare denial at this scale. During the Tanker War (1987 to 1988), mines and missile boats threatened individual vessels. The current denial threatens the navigational infrastructure itself, degrading the ability of any vessel to determine its own position across a 2,500-kilometre corridor. The Houthis threatened Bab al-Mandeb closure the day after Pakistan confirmed talks had stalled.

Vessels diverting from Hormuz toward the Red Sea now navigate degraded positioning systems approaching a second contested chokepoint. Roughly 4.5 million barrels per day and 12% of global trade pass through Bab al-Mandeb. Combined with near-total Hormuz closure, the world's two most important oil chokepoints are under simultaneous pressure for the first time since the 1973 oil crisis ². The Cape of Good Hope route adds 10 to 14 days and $500,000 to $1 million per voyage in fuel costs.

Deep Analysis

In plain English

Ships navigate using GPS-style satellite signals. Someone is deliberately jamming those signals across a 2,500-kilometre corridor stretching from the Strait of Hormuz in the Gulf to the Bab al-Mandeb in the Red Sea. This matters because ships diverted away from Hormuz (which Iran controls) have been heading toward the Red Sea instead. The GNSS jamming makes that alternative route significantly more dangerous, because ships cannot accurately determine their own position. The practical effect: there is now no safe, insurable sea route between the Gulf and global markets. Ships must go around Africa instead, adding 10 to 14 days and significant fuel costs to every voyage.

Source Landscape

This story draws on neutral-leaning sources

Primary parallel: The Tanker War of 1987-88 saw Iran and Iraq attack vessels in The Gulf, leading to Operation Earnest Will — US Navy convoy protection through Hormuz. The threat was kinetic and localised. The current electronic denial operates across a 2,500-kilometre corridor simultaneously.

Counter-parallel: Operation Earnest Will succeeded because the threat was to individual vessels from mines and missiles, allowing convoy protection. There is no analogous response to a denial zone that degrades navigation infrastructure across two entire sea lanes.

The Cape of Good Hope detour adds 10 to 14 days and $500,000 to $1 million per voyage. Combined GNSS denial and the physical threat at both chokepoints effectively makes the Cape route the only commercially viable option for most carriers.

Insurance costs for Gulf and Red Sea transits have already risen sharply. The combined GNSS denial zone eliminates the risk-reduction argument that the Red Sea is a safer alternative to Hormuz.

Consensus view: RUSI maritime security researchers and Lloyd's List Intelligence assess the GNSS denial corridor as a layered access denial strategy: degrading navigation instrumentation reduces both commercial willingness to transit and the tactical effectiveness of any anti-IRGC naval operation.

Counter-view: The Turkish maritime authority UDHB and Chinese COSCO maritime risk analysts note that modern vessels carry inertial navigation backups and that the denial zone, while severe, does not render transit physically impossible — it increases risk and insurance cost rather than creating a hard barrier.

Key tension: Whether the GNSS denial zone is a direct precursor to kinetic action against vessels attempting the Red Sea detour, or a sustained electronic deterrent intended to raise costs without triggering a new military confrontation.

Sources:International Maritime Organisation / UKMTO·US Maritime Administration

Mentions:Strait of Hormuz →Pakistan →Iran →Bab al-Mandeb →Islamic Revolutionary Guard Corps (IRGC) →Houthis →UKMTO →

First Reported In

Update #51 · Iran hits aluminium plants; Hormuz emptying

International Maritime Organisation / UKMTO· 29 Mar 2026

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Causes and effects

Caused by

Houthis threaten to close Bab al-Mandeb

The GNSS denial zone extending to Bab al-Mandeb is the electronic precursor to the physical closure threatened by Houthi minister Mansour.

Occurred 28 Mar 2026

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This Event

GPS blacked out across Gulf chokepoints

The deliberate GNSS denial zone eliminates the Red Sea as an alternative to Hormuz, trapping commercial shipping between two contested chokepoints with degraded navigation systems.

Led to

Houthis threaten second chokepoint

GNSS denial across both chokepoints supports the coordinated Houthi-Iran electronic warfare enabling the sustained missile campaign against Israel.

Occurred 30 Mar 2026

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Different Perspectives

India (BRICS meeting host, grey-market beneficiary)

New Delhi hosted the BRICS foreign ministers' meeting on 14 May that Araghchi attended under the Minab168 designation, giving India a front-row seat to Iran's diplomatic positioning. India's state refiners have been absorbing discounted Iranian crude through grey-market routing since April; Brent at $109.30 means every barrel sourced outside the formal market generates a structural saving.

Hengaw / Kurdish human rights monitors

Hengaw's daily reports from Iran's Kurdish provinces remain the sole independent cross-check on Iran's judicial activity during the conflict. Two executions across Qom and Karaj Central prisons on 15 May and five Kurdish detentions on 15-16 May indicate the wartime judicial pipeline is operating independently of military tempo.

Pakistan (mediator and bilateral partner)

Islamabad spent its diplomatic capital as the US-Iran MOU carrier to secure LNG passage for two Qatari vessels through a bilateral Pakistan-Iran agreement, spending its mediation credit for direct economic gain. China's public endorsement of Pakistan's mediatory role on 13 May is the structural reward.

China and BRICS bloc

Beijing endorsed Pakistan's mediatory role on 13 May, one day after the BRICS foreign ministers' meeting in New Delhi. Chinese state banks are processing PGSA yuan toll payments; China has not commented on its vessels' continued Hormuz passage, but benefits structurally from a non-dollar toll system it did not design.

Iraq (bilateral passage partner)

Baghdad negotiated a 2-million-barrel VLCC transit without paying PGSA yuan tolls, offering political alignment in lieu of cash. Iraq's position inside Iran's adjacent bloc makes it the natural first bilateral partner and a template for how Tehran structures passage deals with states that cannot afford Western coalition membership.

Bahrain and Qatar (Gulf signatories)

Both signed the Western coalition paper while hosting US Fifth Fleet and CENTCOM's Al Udeid base, respectively. Qatar occupies the sharpest contradiction: it is on coalition paper while simultaneously receiving LNG passage through the bilateral Iran-Pakistan track, a position Doha has tacitly accepted from both sides.