Gulf ship signals sharpen as interference fades

Electronic interference that had scrambled vessel tracking across the Persian Gulf eased over the weekend, allowing ships stranded in the war-affected waterway to show positions closer to their true locations and giving operators a clearer picture of navigation risks in one of the world’s most important energy corridors. Maritime security guidance issued on 29 March said GNSS, GPS and AIS disruption had moderated over the previous 24 to 48 hours and was now judged “sporadic and localised”, a marked change from the more severe distortion that had obscured ship movements earlier this month.

That shift matters because false signals had become a serious operational hazard as the conflict around Iran and the Strait of Hormuz intensified. During the worst of the disruption, ships appeared to be moving at implausible speeds, clustering in unlikely formations, or showing positions on land and near sensitive installations rather than at sea. Windward, a maritime analytics firm, said more than 1,100 vessels were affected within 24 hours at the start of March, while later assessments pointed to even broader disruption across Gulf waters.

The easing of jamming does not mean the danger has passed. The Joint Maritime Information Center’s earlier advisories had placed the wider maritime environment at critical risk after missile and drone attacks on commercial shipping, and official updates said at least 20 maritime security incidents involving merchant vessels and offshore infrastructure had been reported across the Arabian Gulf, Strait of Hormuz and Gulf of Oman since 1 March. The navigational picture may be less confused than it was days ago, but the military threat environment remains elevated.

For shipping companies, charterers and insurers, the clearer signal picture is useful mainly because it restores a measure of visibility, not because it guarantees safer passage. Bloomberg reported that the moderation in interference helped reduce immediate concerns about how to navigate vessels trapped in the inland sea, yet traffic patterns through Hormuz remain far below normal. Earlier this month, reporting showed departures collapsing as jamming combined with missile and drone strikes to choke movements through the narrow passage between Iran and Oman.

The commercial consequences have been broad. The Strait of Hormuz is a chokepoint for a large share of global seaborne oil and liquefied natural gas trade, so any prolonged disruption quickly feeds into freight rates, insurance costs and energy market anxiety. World Shipping Council said around 20,000 seafarers operating in the Middle East were facing a dangerous and highly uncertain security situation, while union and employer bodies designated the strait and surrounding waters a warlike operations area, giving some crews enhanced protections and the option to refuse entry under certain agreements.

There are also signs that some movements are resuming, though cautiously and unevenly. Seatrade Maritime, citing the latest advisory, said the fall in interference coincided with an increase in transits on 27 and 28 March. Even so, not every operator has been willing to test the route. Reuters reported on 27 March that two Chinese container ships turned back after attempting to leave the Gulf despite Iranian assurances of safe passage for Chinese vessels, underlining how political guarantees and real-time seamanship calculations are not always aligned.

The region’s shipping authorities and governments have responded with tighter monitoring. On 3 March, the Ministry of Ports, Shipping and Waterways said it had enhanced precautions to protect Indian-flagged vessels and Indian seafarers in the Persian Gulf, including a dedicated response mechanism and closer review of maritime risks. Industry groups have meanwhile urged masters to maintain contact with UKMTO, review emergency procedures and prepare for abrupt changes in transit conditions, reflecting the reality that electronic disruption is only one layer of a broader security problem.