U.S. Maritime Advisory 2024-008

Geographic Location: Southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden
Description: Houthi Attacks on Commercial Vessels

1. References:

This advisory is extracted from U.S. Maritime Advisory 2024-006 to provide clarity for threats in this geographic region. U.S. Maritime Advisory 2024-006 is canceled.

2. Issue: Commercial vessels are at highest risk from terrorism and other hostile actions from the Houthis when transiting the southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden. Hostile actions include one-way Unmanned Aerial Vehicle (UAV) attacks; Unmanned Surface Vehicle (USV) attacks; ballistic and cruise missile attacks; small arms fire from small boats; explosive boat attacks; and illegal boardings, detentions, and/or seizures. Since November 1, 2023, there have been at least 88 separate Houthi attacks on commercial vessels and one Houthi seizure of a commercial vessel in these areas, affecting over 55 nations. Entities claiming to be Yemeni authorities have also attempted to divert commercial vessels operating in these regions from their course. These threats pose both direct and collateral risks to commercial vessels transiting in international shipping lanes, or otherwise operating in these areas. Commercial vessels operating in these areas should be vigilant for hazards to navigation caused by vessels being struck by the Houthis and should be aware of all current navigation warnings.

The U.S. government is continually assessing the maritime security situation in the region to safeguard freedom of navigation, ensure the free flow of commerce, and protect U.S. vessels, personnel, and interests. Operation Prosperity Guardian and European Union Naval Force (EUNAVFOR) Operation Aspides are examples of U.S. and international cooperative maritime security operations within this region.

3. Guidance:

U.S.-flagged commercial vessels transiting the southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden with Automatic Identification System (AIS) transponders on are at increased risk of targeting by adversarial actors.

U.S.-flagged commercial vessels operating in these areas are strongly advised to turn off their AIS transponders, unless vessel Masters believe that doing so would compromise the safety of the vessel. The International Convention for the Safety of Life at Sea (SOLAS), Chapter V, regulation 19.2.4, and IMO Assembly Resolution A 29/Res.1106 permit vessel Masters to turn AIS off if they "believe that the continual operation of AIS might compromise the safety or security of their ship, or where security incidents are imminent." See also 33 CFR § 164.46(d)(2)(v). While vessels have been attacked by the Houthis while AIS transponders were on and while off, turning AIS off makes it more difficult to track and accurately target a vessel. Adherence to all flag state and international requirements and guidance regarding operation of AIS, and the safe navigation of the vessel, remains the responsibility of individual companies and vessel Masters.

U.S.-flagged commercial vessels operating in these areas are advised to remain as far as possible from Yemen’s coastline without compromising navigational safety. Crewmembers should be especially vigilant when at anchor, operating in restricted maneuvering conditions, loitering, or proceeding at slow speeds.

U.S.-flagged commercial vessels should coordinate voyage planning with U.S. Naval Forces Central Command (NAVCENT) Naval Cooperation and Guidance for Shipping (NCAGS) and consider their recommendations and guidance whenever possible. NAVCENT NCAGS stands a 24-hour watch and has the latest information on the current maritime security threats and the operational environment in this region.

The route taken through these areas and the timing of transits remain at the discretion of individual companies and vessel Masters. Planned routes, waypoints, and speeds should not be duplicated from prior voyages, when possible. Transiting these areas during hours of darkness may frustrate efforts to target vessels. If AIS is secured, U.S.-flagged commercial vessels are advised to provide hourly positional updates by email to the NAVCENT NCAGS detachment when transiting these areas.
Maritime operators are advised to alert their crews to the fact that all electronic signals from their vessels pose a risk to maritime operations and are strongly advised to secure Wi-Fi routers while underway in these areas when feasible.

U.S.-flagged commercial vessels carrying flammable, explosive, or otherwise hazardous cargoes are strongly advised to reconsider transit through these areas. However, if planning voyages through these areas, vessels should take all prudent safety precautions, including thoroughly preparing for emergency responses, and consider carriage of additional safety and damage control preparedness supplies and equipment.

If hailed on VHF by the Houthis, or entities claiming to be Yemeni authorities, and instructed to divert from their course or submit voyage information, U.S.-flagged commercial vessels should ignore the VHF call and continue their passage if safe to do so. U.S.-flagged commercial vessels that encounter these tactics are advised not to follow Houthi direction, as doing so may enhance the ability of the Houthis to accurately target vessels. U.S.-flagged commercial vessels are advised to update the NAVCENT NCAGS detachment when any such communications occur.

If the Houthis seek to board a U.S.-flagged commercial vessel in these areas, the vessel’s Master should, if the safety of the ship and crew would not be compromised, decline permission to board, noting that the vessel is proceeding in accordance with international law, as reflected in the Law of the Sea Convention.

When combined with evasive maneuvering, vessels transiting these areas with armed security details onboard have successfully deterred boarding by individuals in approaching small craft and Unmanned Surface Vehicle attacks. The decision whether to embark a contracted armed security detail and assessment of associated risks is the responsibility of individual companies and vessel Masters, who are responsible for establishing use of force guidance and pre-planned responses for vessels carrying contracted armed security details.

If Houthis board a U.S.-flagged commercial vessel without a contracted armed security detail onboard, the crew should not forcibly resist the boarding party. Refraining from forcible resistance does not imply consent or agreement to that boarding.

When operating in these waters, U.S.-flagged commercial vessels should always maintain a proper, vigilant lookout by employing all suitable means in the prevailing circumstances and conditions. This includes incorporating additional lookouts to ensure a comprehensive assessment of the situation. See 1972 COLREGS, Rule 5. If U.S.-flagged commercial vessels observe or hear a suspected UAV or missile or observe a small boat approaching with apparent hostile intent, crewmembers not needed for the safe navigation and operation of the vessel should be relocated to a safe space until the threat has passed. Additional precautions should be taken to ensure small boats are kept at a safe distance whenever possible.

In addition to U.S. Maritime Alerts and this Advisory, interim industry transit advice for the Southern Red Sea and Gulf of Aden is being distributed by Combined Maritime Forces (CMF). CMF guidance messages are available on the Maritime Global Security website at maritimeglobalsecurity.org/geography/goa-etc/.

The Red Sea/Gulf of Aden Joint Maritime Information Center (JMIC), a collaborative effort among Combined Maritime Forces, the Singapore Navy’s Information Fusion Center, the Royal Netherlands Navy’s NCAGS, the U.S. Navy Fifth Fleet’s NCAGS, and others, is now providing a Weekly Dashboard and incident specific Info Notes regarding threats and incidents in this region at https://www.ukmto.org/indian-ocean/jmic-products.

The Best Management Practices to Deter Piracy and Enhance Maritime Security in the Red Sea, Gulf of Aden, Indian Ocean and Arabian Sea, and Maritime Global Security website at: https://www.maritimeglobalsecurity.org should be consulted prior to operating in those geographic waters.

Transit by yachts and privately owned sailing vessels through these waters is hazardous and may result in capture. The U.S. Government advises against all operation of yachts and pleasure craft in these areas.

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) at: https://step.state.gov/step/. Yachting guidance can be found at: https://on-shore.mschoa.org/reference-documents/advice-for-sailing-vessels/.

U.S.-flagged commercial vessels operating in these waters are advised to conduct a pre-voyage risk assessment, incorporate appropriate protective measures into vessel security plans, exercise caution, and monitor VHF Channel 16. In the event of any attack, incident, or suspicious activity, immediately: activate the Ship Security Alert System, contact the U.S. Fifth Fleet Battle Watch, and contact UKMTO.

U.S.-flagged commercial vessels should register with the United Kingdom Maritime Trade Office (UKMTO) watch and may contact NAVCENT NCAGS 24 hours prior to entering the Indian Ocean Voluntary Reporting Area by sending UKMTO, and if desired NAVCENT NCAGS, a single e-mail, the Initial Report from Annex D of (BMP). Include the estimated times of arrival at the Suez Canal, Bab el Mandeb Strait (BAM), and if applicable, the Strait of Hormuz (SoH) in line 10 of the report and add line 14 for comments as needed (e.g., speed restrictions or other constraints, anticipated time of entering/exiting the SoH Traffic Separation Scheme; an outline of the navigation plan for operating in the SoH and Persian Gulf, etc.). Utilize other reports included in Annex D of BMP as necessary.
Vessels operating in this area are advised to include the NAVCENT NCAGS watch on all updates or incident report emails so as not to create an additional reporting burden.

The Maritime Global Security website at https://www.maritimeglobalsecurity.org/ offers industry issued best practices and guidance to mariners by geographic region and provides contact and subscription information for regional maritime security reporting centers, particularly in high risk-areas.

Answer all VHF calls from coalition navies. Vessels should be aware that U.S. and other coalition naval forces may conduct maritime awareness calls, queries, and approaches to ensure the safety of vessels transiting these listed waters.

Due to the risks of piracy, kidnapping, hijacking, and robbery while operating within U.S. Coast Guard designated High-Risk Waters (HRW), U.S.-flagged commercial vessels are required to comply with the Guidelines for U.S. Vessels Operating in High-Risk Waters contained in U.S. Coast Guard Maritime Security Directive 104-6 (Rev 8) and comply with their Coast Guard approved Vessel Security Plan annex on counter piracy. The U.S. Coast Guard Office of Commercial Vessel Compliance (CG-CVC) announced in the Federal Register in August 2021 the availability of Revision 8 to Maritime Security (MARSEC) Directive 104–6. U.S. vessel owners and operators who needed to act under previous versions of MARSEC Directive 104–6 should immediately contact their local Coast Guard Captain of the Port or District Commander for a copy of Revision 8.

Per 33 CFR 101.305, report all suspicious activities, breaches of security, and transportation security incident events involving U.S. vessels or persons to the U.S. Coast Guard National Response Center. Additional U.S. Coast Guard port specific requirements may be found in Port Security Advisory 1-22 at https://www.dco.uscg.mil/Portals/9/DCO%20Documents/InternationalPortSecurity/Port%20Security%20Advisory/PSA%20%201-22%20Remove%20Cote%20d'Ivoire.pdf?ver=6DzYOEsWAJQVh7ld4c0ycQ%3d%3d.

4. Contact Information:

a) Fifth Fleet Battle Watch: cusnc.bwc@me.navy.mil or + 973-1785-3879.

b) NAVCENT NCAGS: +973-1785-0033 (Primary/Watch Desk), +973-3940-4523 (Alternate), or m-ba-navcent-ncags@us.navy.mil.

c) UKMTO: watchkeepers@ukmto.org or +44 (0) 2392 222060. UKMTO advisories and warnings are available at https://www.ukmto.org/.

d) U.S. Coast Guard National Response Center: +1-800-424-8802.

5. Cancellation of Prior Advisories: This message supersedes and cancels U.S. Maritime Advisory 2024-06 and will automatically expire on February 12, 2025.

For maritime industry questions about this Advisory, contact the Global Maritime Operational Threat Response Coordination Center at GMCC@uscg.mil. Supplemental information about U.S. Maritime Alerts and Advisories, including subscription details, may be found at: https://www.maritime.dot.gov/msci. Feedback provided by U.S. maritime industry stakeholders regarding the U.S. Maritime Advisory System has greatly supported the USG in pursuing continued enhancements to this system. Feedback to MARADSecurity@dot.gov is always welcome.