U.S. flagged commercial vessels in the region should operate under a heightened state of alert due to the potential for direct or collateral damage. These threats may come from a variety of different sources including, but not limited to, missiles, projectiles, mines, small arms, or waterborne improvised explosive devices. Vessels in this region should report hostile activities immediately and contact coalition naval forces on VHF Channel 16.
U.S. flagged commercial vessels should also make contact in advance with the U.S. Fifth Fleet Naval Cooperation and Guidance for Shipping (NCAGS) detachment. Suspicious activities and events are also required to be reported by U.S. flag commercial vessels to the U.S. Coast Guard National Response Center. Vessels operating in this region are also advised to establish contact with the United Kingdom Maritime Trade Office (UKMTO).
Transit by yachts and privately owned sailing vessels through the region is also extremely hazardous and may result in capture. The U.S. Coast Guard advises against all operation of yacht and pleasure craft in these areas. Vessels that make this passage despite this advisory should make contact in advance with NCAGS. American citizens abroad should inform the nearest U.S. embassy or consulate of their plans to transit the area and/or update their information via the Smart Traveler Enrollment Program (STEP).
Please view more details by reading the US MARAD Advisory here.
Source: US MARAD