At least 18 attacks on merchant ships have been reported across the region this month, and Iran has now raised the stakes further: any vessel that switches off its identification and tracking equipment during what Tehran deems an unauthorised transit of the Strait of Hormuz will be treated as hostile.

The warning landed as fresh details emerged of a wave of strikes on October 11 that extended beyond tankers to containerships — a widening of the target set that directly implicates liner operators and their cargo interests, not just the crude and product trades.

UK Maritime Trade Operations (UKMTO) issued four retrospective alerts on Monday covering three tankers and a containership struck on October 11, bringing the day's reported total to six. An unidentified projectile struck the boxship as it entered Hormuz. A crude tanker, a product tanker and another tanker were hit during outbound transits. Vessel identities and the extent of damage were not immediately disclosed.

What did the IRGC claim?

Iran's Islamic Revolutionary Guard Corps claimed to have attacked a VLCC attempting to transit the strait without permission. The corps released footage purportedly showing the fire-damaged Al Maqam, a 298,800 dwt tanker owned by ADNOC Logistics & Services.

ADNOC has declined to comment. It remains unclear whether the purported strike on the Al Maqam sits among the incidents UKMTO reported or represents an additional attack — a gap in the record that shippers and underwriters will want closed before pricing risk.

The scale is easy to grasp in tonnage terms: a single VLCC of nearly 300,000 dwt carries roughly two million barrels of crude, so any sustained threat to that class of vessel in Hormuz touches a significant share of seaborne oil supply at its chokepoint.

What about the crews?

Two Indian seafarers remain missing after Sunday's drone strike on the Nicaragua-flagged Petro Dolphin off Sohar, Oman. Nine crewmembers were rescued.

The latest violence follows Saturday's American airstrike against the Panama-flagged Ocean Molica in the Gulf of Oman. Washington accused the vessel of attempting to breach its naval blockade of Iranian ports — the first public framing of the conflict in terms of an active blockade enforcement, not isolated strikes.

Why does the 'going dark' warning matter?

For carriers and forwarders, the threat against AIS-switched-off vessels inverts the usual risk calculus. Masters have sometimes disabled transponders in high-risk waters to avoid being targeted by tracking data; Iran's warning now treats that very practice as grounds for a hostile response.

The commercial consequences are already visible in the target mix. What began as a tanker-focused campaign has now drawn in a containership at the Hormuz entrance, meaning box operators calling at Gulf ports face the same exposure as energy carriers — with the added complication that a single boxship hit can strand thousands of TEU of cargo and trigger general average and delay claims across many cargo interests at once.

Vessel identities remain undisclosed for the October 11 strikes, so operators cannot yet confirm whether their chartered tonnage was involved. That absence of attribution is itself a cost: war-risk premiums for Gulf transits are typically quoted against verified incident data, and an unattributed cluster of six attacks in one day gives underwriters every reason to widen rather than narrow their pricing.

The numbers to watch are simple. Eighteen reported attacks in a single month, six in one day, and a state actor now publicly committing to treat dark transits as hostile — each figure points in the same direction: the risk premium on Hormuz traffic is set to rise before it falls.

By Marcus Bennett