Iran Files IMO Protest Over US Channel 16 Use in Gulf

Iran Accuses US Military of Misusing Distress Channel

According to a report by The Maritime Executive, Iran has submitted a formal protest to the International Maritime Organization alleging that United States forces are abusing VHF Channel 16 — the globally designated frequency for distress, urgency, and brief safety calls — for what Tehran calls military intimidation and psychological pressure against civilian crews operating in the Persian Gulf.

In a letter filed with the IMO, Iran’s ambassador and permanent representative said the country’s government directed the mission to raise concerns over maritime security, distress communications, and seafarer safety in the region. The letter states that commercial vessels, shipping companies, and maritime operators have reported misuse of the channel by US military units.

Allegations of Threatening Communications

Iran’s submission claims that Iranian seafarers have been addressed in Persian using threatening, abusive, and provocative language over the channel, with some crews reportedly told to abandon their ships. Tehran argues this has interfered with the channel’s core purpose and placed undue psychological strain on civilian crews, describing the conduct as a breach of SOLAS safety-communication obligations.

The protest notably omits any reference to the attacks Iran itself has been linked to in the region. The IMO’s own tally puts the number of Iranian-attributed incidents in October alone at 15, part of a broader total of 106 incidents since the conflict began, resulting in 24 fatalities, two missing sailors, and twelve injuries — the very conditions generating the distress traffic in question.

Blockade Context

The backdrop to this dispute is the US blockade of Iranian ports, resumed on July 14 by US Central Command. As of October 10, CENTCOM reported four commercial vessels disabled and 135 ships turned back during three months of enforcement, alongside the destruction of ten tankers it links to the Islamic Revolutionary Guard Corps’ sanctions-evasion network. A Panama-flagged bulk carrier was also disabled on October 10 for allegedly attempting to breach the blockade.

Iran’s IMO filing appears to be one of several pressure tactics aimed at the US as American midterm elections approach. The US has signaled it will maintain its current posture at least until the elections, with the possibility of resuming more aggressive action afterward.

What This Means for Owners and Operators

For ship owners, managers, and charterers with tonnage transiting the Persian Gulf and Strait of Hormuz, this dispute is a reminder that safety communications themselves have become contested ground in an already volatile theater. Regardless of how the IMO responds to Iran’s complaint, masters and crews operating in the region should expect continued ambiguity over radio traffic on Channel 16, and should maintain rigorous, documented logs of any unusual or threatening communications received. This record-keeping matters not only for safety management but for insurance, P&I, and charterparty disputes that may follow an incident.

The broader pattern — rising incident counts, blockade enforcement actions, and diplomatic protests — also underscores the value of independent condition and pre-fixture surveys before vessels commit to Gulf transits. Verifying a ship’s seaworthiness, communications equipment, and crew readiness in advance reduces exposure when operating in a zone where distress signaling itself is now disputed territory. Charterers and managers routing vessels through the Strait of Hormuz should treat current conditions as a standing operational risk requiring enhanced due diligence, not a temporary disruption.

The IMO has not yet indicated what action, if any, it will take in response to Iran’s request that the letter be circulated to all member states.