Charter disputes tied to vessels going dark in the Strait of Hormuz are increasing as legal commentary and maritime intelligence providers report growing evidentiary conflicts over what occurs when ships switch off their Automatic Identification System (AIS) transponders, according to a report published by Windward.
According to Windward, the Strait of Hormuz has operated outside normal traffic patterns since the outbreak of the Iran conflict on February 28, 2026. Visible AIS transits fell sharply, from approximately 3,750 monthly transits in February 2026 to 450 in March, with figures fluctuating through the following months. Windward reports that even after a partial recovery, June 2026 transits remained roughly 83% below pre-conflict baselines.
A Recurring Dispute Pattern
Windward describes a recurring charter dispute pattern: a vessel enters the Hormuz war-risk zone, switches off AIS for a defined period, and upon resuming broadcast, the charterer alleges that an unreported ship-to-ship transfer, unscheduled port call, or cargo diversion occurred during the dark window. Owners typically maintain that the AIS switch-off was a legitimate safety or security measure and that no unauthorized activity took place.
The report notes that legal commentary through 2026, including analysis from Holland & Knight and P&I club guidance referenced by Windward, has flagged rising exposure to charter disputes involving force majeure, frustration doctrine, safe-port warranties, and AIS switch-off clauses. Windward points to the BIMCO AIS Switch Off Clause for Time and Voyage Charter Parties 2021, which requires owners to warrant that AIS silencing was not used contrary to IMO guidance, as shifting dispute focus toward what actually happened during the dark period rather than whether AIS was switched off.
Windward also cites the English Court of Appeal ruling in Tonzip Maritime (Singapore) Pte Ltd v 2 Rivers Pte Ltd, “The Catalan Sea” [2026] EWCA Civ 641, handed down May 22, 2026, which clarified that invoking sanctions clauses in charterparties requires only a reasonable judgment of real sanctions risk rather than proof that a breach would probably occur.
Scale of Dark Transits
According to Windward’s tracking data, dark transits have become a substantial share of Hormuz traffic. On July 28, 2026, Windward recorded 16 inbound AIS-visible transits, 8 outbound AIS-visible transits, and 17 dark transits, meaning dark traffic exceeded either visible category that day.
To reconstruct vessel activity during dark periods, Windward states it draws on satellite imagery (including Synthetic Aperture Radar and electro-optical imagery), radio frequency detection, and behavioral pattern analysis, combining these into what it describes as a documented reconstruction for use by legal counsel and arbitrators.
Does This Matter to You?
The increase in dark transits and associated litigation risk described by Windward has direct implications for parties involved in Hormuz-related charterparties and cargo arrangements. War-risk premiums for Hormuz transits have risen from roughly 0.25% of hull value pre-conflict to between 3% and 10% at various points in 2026, according to insurance market coverage cited by Windward. Parties navigating charterparty terms, safe-port warranties, and AIS-related clauses in this region may face increased evidentiary and contractual uncertainty when disputes arise over unreported vessel activity during dark periods.
Gulf Bunkering does not provide operational or security guidance. This article is for informational purposes only. Operators should consult flag state authorities, P&I clubs, and relevant advisories for decisions relating to transit planning.
Sources: Windward
