The U.S. restricts tankers from transiting through the Strait of Hormuz during air-defense windows
On September 12, Reuters reported that the United States has asked tankers transiting through the Strait of Hormuz to sail only during specific time windows to ensure military protection. Previously, Iran increased attacks on ships transiting at night. Since May, Washington has been providing air defense to vessels hoping to travel via a route close to the coast of Oman along the southern side of the strait, in order to counter Iranian attacks and keep some oil flowing out of the Gulf.

Shipowners must apply to the U.S. Naval Coordination and Guidance Service (NCAGS), which then provides crews with the coordinates to follow and allows them to transit during a wider nighttime time window, during which they can receive protection from U.S. aircraft. Emails sent from NCAGS to a maritime adviser show that this window was reduced to two specific daily time windows around early September, and ships are required to begin their transit at the specified times.

One email said they provide daily different recommended transit times, and ships are not required to follow them, but it is advised that they do. Another email said that given the threats faced by commercial vessels, “transiting during hours of darkness has been shown not to be the safest time of day.”