Ghost Ships in the Strait: How Iran-Linked Spoofing Forced Traders to Abandon AIS Tracking
As vessel signals vanish and transponders lie in the Strait of Hormuz, insurers and traders rely on satellite imagery and behavioral analytics to track 21% of global oil supply through a contested digital fog.
Field investigations in the Strait of Hormuz reveal AIS data may be underreporting actual vessel traffic by as much as 50%, according to Tradlinx, citing research from Citrini Research and corroborated by multiple maritime intelligence firms. The critical chokepoint—carrying 21 million barrels of oil per day, or 21% of global consumption—has transformed from a physical bottleneck into what maritime technology investor Erik Bethel calls a “contested information environment” where traditional tracking systems no longer reflect reality.
The Strait of Hormuz crisis began February 28, 2026, when US and Israeli airstrikes on Iran triggered an Iranian closure and maritime deception campaign. A two-week ceasefire announced April 8 collapsed after Iran cited continued attacks on Lebanon. Since April 13, a US naval blockade of Iranian ports has created a dual-enforcement regime alongside Iran’s selective transit controls.
The Scale of the Deception
On April 6, Windward identified 267 AIS-dark events in a single day. By April 17, that figure climbed to 162 dark activity events—the highest reading of the crisis. Pole Star Global reports roughly one in ten vessels in the Gulf now display anomalous AIS behavior, including spoofing, electronic interference, and transponder deactivation.
The manipulation techniques have grown increasingly sophisticated. “Now, we are starting to see vessels going dark or using ‘zombie’ or random identification,” Ami Daniel, CEO of Windward, told Gulf News. Satellite imagery from April 16 at 07:22 UTC identified seven VLCCs, one Suezmax, and two Aframax vessels in the Kharg region—one Aframax transmitting AIS under a fraudulent Curaçao flag.
How Traders Adapted
With AIS reliability shattered, maritime intelligence firms pivoted to synthetic aperture radar (SAR) satellite imagery, which cannot be spoofed. Windward confirmed VLCC RHN (IMO 9208215), broadcasting a fraudulent Curaçao flag, crossed the strait on April 15 and was verified via SAR imagery on April 16 at 02:22 UTC, likely attempting a Kharg Island loading run.
“You need to layer behavioural analytics, voyage history and cargo intelligence to understand what is genuinely happening,” Dimitris Ampatzidis, maritime risk and compliance manager at Kpler, explained in The National. The shift represents a fundamental break from decades of AIS-based tracking: insurers and traders now triangulate vessel positions using satellite radar, historical routing patterns, and crowdsourced anomaly detection rather than trusting transponder signals.
Windward currently tracks approximately 177 vessels carrying Iranian cargo worldwide and approximately 700 Iranian dark-fleet vessels operating globally. The company’s AI-assisted behavioral analytics flag vessels that deviate from normal routing, switch flags mid-voyage, or exhibit AIS patterns inconsistent with their stated destinations.
“At sea, vessel-level behaviour reflects a fragmented picture. Some vessels are reversing course, others are drifting after clearing the strait, while some continue operating under reduced visibility or inconsistent routing patterns.”
— Windward, maritime AI company
The Insurance Crisis
War-risk Insurance premiums surged from 0.125% of vessel value pre-conflict to between 0.2% and 0.4% in late February. By early March, premiums reached 1%. As of late March, quotes ranged between 5% and 10% of hull value—making a single transit through Hormuz potentially more expensive than a year’s premium under normal conditions.
The premium spike reflects more than physical risk. Insurers cannot accurately price exposure when they cannot verify vessel locations. “It is admittedly quite difficult to get an accurate picture of what goes on,” Jakob Larsen, chief safety and security officer at the Bimco shipping association, told The National. That opacity forces underwriters to price worst-case scenarios, effectively rendering commercial transit economically prohibitive for all but the highest-value cargoes.
The Enforcement Challenge
The US naval blockade, which began April 13, has turned back at least ten vessels in its first days. But enforcement depends on the same intelligence systems Iran-linked operators are systematically undermining. “A blockade is only as strong as the intelligence behind the interdictions,” Bethel noted in Gulf News.
Daily ship transits through the strait plunged from approximately 140 pre-crisis to only 8 vessels on April 17, representing a 94% decline. On April 15, observers counted 15 vessels mid- or post-transit (8 inbound, 7 outbound). By April 17, only 8 vessels transited (5 inbound, 3 outbound), per Kpler data cited by The National.
Bypassing the strait entirely remains constrained by infrastructure. Saudi Arabia’s East-West Pipeline operates at approximately 5.2 million barrels per day capacity as of April 12. Combined with UAE and other regional bypass routes, total alternative capacity stands at only 2.6-3.5 million barrels per day—roughly 15% of the strait’s normal 21 million barrel daily flow.
| Route | Capacity (mb/d) | % of Normal Hormuz |
|---|---|---|
| Saudi East-West Pipeline | 5.2 | 25% |
| UAE & Other Bypasses | 1.5-1.8 | 7-9% |
| Total Alternative Capacity | ~2.6-3.5 | 12-17% |
| Normal Hormuz Flow | 21.0 | 100% |
Oil Market Response
Brent crude traded at $95.93 per barrel as of April 17 at 12:07 PM GMT, according to Trading Economics, down from $94.89 on April 16. The modest decline reflects ceasefire negotiation sentiment rather than fundamental supply relief—with bypass infrastructure handling less than one-sixth of normal flows, the strait’s closure keeps structural tightness in place even as speculative positioning adjusts to diplomatic headlines.
- AIS data may underreport Hormuz vessel traffic by 50%, forcing reliance on SAR satellite imagery
- War-risk insurance premiums reached 5-10% of vessel hull value by late March 2026
- Only 8 vessels transited the strait on April 17, down 94% from pre-crisis levels of ~140 daily
- Alternative pipelines can handle just 12-17% of normal Hormuz oil flows
- 162 AIS dark events recorded April 17—the crisis peak
What to Watch
The operational question now centers on whether US enforcement can close the intelligence gap Iran-linked operators have exploited. Windward reports “the operating environment is entering an active enforcement phase, where compliance, evasion, deceptive shipping practices and continued limited movement are all occurring simultaneously.”
Monitor three indicators: first, whether SAR satellite providers expand coverage frequency in the Gulf, reducing the window for dark transits. Second, whether insurance premiums stabilise or continue rising as underwriters refine their behavioral analytics models. Third, whether US interdiction rates climb as AI-assisted vessel classification improves—or whether spoofing techniques evolve faster than detection capabilities. The strait’s 21% share of global oil supply means the outcome determines not just regional trade flows but the baseline risk premium in global Energy markets for the foreseeable future.