Naval Vessel Traffic Services

Vessel traffic services (VTSs) ensure the safe and efficient handling of traffic on busy waterways like the approaches to New York. That has been the raison d’être of VTS, but this technique, wherein electronic sensors and communication systems are used to manage traffic actively, and can be used in maritime security operations (MSOs) to enhance safety in areas with risks related to asymmetric threats.¹ A limited form of VTS is deployed for MSOs situated in international waters. These services, provided by naval cooperation and guidance for shipping (NCAGS) organizations, are focused on building maritime domain awareness (MDA) and providing naval-related safety information to merchant shipping. Structuring and monitoring of vessel traffic, unfortunately, is supported only poorly, or not at all, by NCAGS.² This is a serious omission, as structuring and monitoring vessel traffic make earlier detection of dangerous situations possible, render ships harder to attack, and minimize possible cascading effects to ship traffic from harassment or attack. Moreover, compared to alternatives such as escorts and convoys, there would be less delay to shipping, while the need for military assets may be reduced through improved efficiency.

This idea has led to a new VTS concept, which is termed “Naval VTS.” It combines a voluntary VTS monitoring system with a traffic organization and information service aimed at providing military commanders responsible for MSOs a level of vessel safety that makes security tasks easier to plan and perform. Navigational risks and risks related to asymmetric threats cannot always be separated, which means that Naval VTS may have to deal with both risks and that it requires flexibility in how it is established.

Another, longer article on this concept was published in the Summer 2010 issue of the Naval War College Review. Last years’ attacks on the UAE-leased HSV Swift and the liquefied natural gas tanker Galicia Spirit in the vicinity of Bab el-Mandeb Strait, however, showed the necessity to bring it under attention again.

 Vessel Traffic Services and Maritime Safety Operations

It is estimated that merchant shipping in 2015 carried more than 80 percent of world trade over a fixed number of maritime routes, the sea lines of communication (SLOCs).⁵ Areas of heightened shipping density on these SLOCs—like the straits of Bab el-Mandeb, Hormuz, and Gibraltar—form choke points. Merchant ships sailing through these choke points are vulnerable to collision, piracy, and terrorism.

Collisions between ships in narrow waterways could practically disrupt vessel traffic for weeks while the wreckage is cleared. In the Strait of Malacca, for instance, such an accident would necessitate rerouting a significant number of merchant ships through the Lombok or Sunda straits. Rerouting causes delays and raises freight rates. This could affect many countries, as the Strait of Malacca is the main SLOC between East Asia and the West.⁶

Piracy and terrorism lead to higher insurance premiums, crew costs, and security costs for ships and could, ultimately, force shipping companies to divert their ships to other, longer routes. This affects freight rates and could jeopardize the security of vital resources. The Strait of Bab el-Mandeb, for instance, had an estimated 4.7 million barrels per day of crude oil and petroleum products passing through it in 2014.⁷ Piracy and terrorism in this strait would be a threat the security of oil supplies. This too could affect many countries because Bab el-Mandeb is an important passage for Persian Gulf oil, liquefied natural gas, and petroleum products to Europe and North America, as well as European and North African oil exports to Asia.

Given the vulnerability of merchant shipping in choke points, where ships present easy targets and consequences could be enormous, it is remarkable that VTS is not already included in maritime security operations.⁸ That is a pity, as merchant ships have significantly changed over the past decades; today, the variations in size, speed, and maneuverability are enormous. This diversity within dense traffic flows, in the face of asymmetric threats, demands active traffic management to reduce risks. The absence of VTS activities in MSOs causes problems in choke points with asymmetric threats and large volumes of traffic:

• Vessel traffic in choke points with no existing VTS center is not organized. The navigational risks inherent to merchant-ship traffic in a confined and congested environment may become unnecessarily high.
• The diversity of the vessel traffic with regard to the possible threats is not addressed. Fast vessels may be exposed to danger longer than necessary.
• Factors affecting the safety of vessels with regard to cascading effects in the event of harassment or attack of other ships are not managed.

The Naval VTS concept could overcome these problems. Like any vessel traffic service, it is a traffic-monitoring system designed to provide support to mariners in busy waterways where risks are deemed greatest. The focus, however, would be on the risks related to asymmetric threats.

The Concept of Naval VTS

Naval VTS is a voluntary vessel traffic service designed to enhance the safety of vessel traffic through confined and busy areas at increased risk, of either a general or specific nature (other than war). It comprises a traffic organization service and an information service.⁹ It is not, however, envisioned as providing navigational assistance, because of potential liability issues and the fact that the infrastructure that would be required in the Naval VTS area for such a service may be absent or damaged (either by lack of maintenance or by the actions of violent nonstate actors).¹⁰

The main purposes of Naval VTS are

• To minimize the risk from harassment or attack on merchant ships
• To minimize the cascading effects on ship traffic from harassment or attack
• To minimize the consequences for the cargo volume transported through the Naval VTS area
• To deconflict merchant-ship movements with military operations
• To enhance vessel safety with regard to the risk inherent to traffic in a confined and congested environment.

Secondarily, in meeting these purposes the concept has the potential to stabilize insurance costs and improve the effectiveness of naval patrols and escorts.

All vessels navigating through a Naval VTS area would be encouraged to participate. Participation would be beneficial to vessels, as it would enhance their safety, and it is beneficial to the Naval VTS organization, as it would contribute to the compilation of the traffic picture. Decisions concerning ships’ actual navigation and maneuvering remain with their masters. Naval VTS guidance would never relieve them from their responsibility to exercise good seamanship and comply with the Collision Regulations.¹¹ To minimize liability, each message directed to a vessel would have to state clearly whether it concerned a question, item of information, advice, or a warning and would use International Maritime Organization (IMO) “standard marine communication phrases” where practicable.¹² Nonparticipating vessels would be briefed on dangers that existed and would be monitored.

A Naval VTS organization in a maritime security operation would consist of a commander and one or more units. These units would be teams of military VTS operators, with specialized equipment, possibly cooperating with existing vessel traffic centers. These units could be ashore or afloat (embarked on either naval or civilian vessels), located at the discretion of the Naval VTS commander. Units would have areas of responsibility, subareas of the Naval VTS area, which are slightly overlapping for contact pass-off and redundancy. All units would have to be equipped with Automatic Identification System (AIS) equipment—receiver, radar, and communications— connected to automated systems to store, update, modify, retrieve, and display collected traffic-picture data. Such equipment, which must be compatible between units and the commander, would give each unit full information about each participating vessel and its intentions. The number of units and level of service provided would depend on the local situation and threat level, and could be adjusted as a situation developed.

Cooperation can be a force multiplier for Naval VTS. Cooperation between the navies participating in MSO could increase the assets and personnel available for Naval VTS. Additionally, cooperation with existing VTS would be particularly valuable when their service areas overlap with that of Naval VTS; use of their surveillance and communication facilities could decrease the assets required to establish Naval VTS. Cooperation with the maritime industry, finally, would make it possible to obtain quickly and cost-effectively all information necessary to maximize maritime domain awareness—such as vessel movements in ports, vessel conditions, hydrographic conditions, and the operational status of aids to navigation.

Commanders of maritime security operations would have authority to activate Naval VTS in their areas. Naval VTS could fit into the normal course of MSO, as participation would be voluntary for all ships and shipmasters would remain responsible for the crews, safe navigation, and handling of their ships. The Naval VTS command-and-control structure and its place within the overall command structure would vary according to the objectives of the operation and the forces participating. Naval VTS commanders, however, would always be responsible for the activities of their organizations.

 Establishing Naval VTS

Implementation of this concept requires a Naval VTS area, traffic organization, Naval VTS units, and communication and emergency procedures. Assembly areas might have to be designated as well.

Naval VTS area. The Naval VTS area is a zone within an area where naval forces are operating in which naval vessel traffic services are to be provided. It must be large enough to cover the waters in which there is an actual threat to shipping, but not so large as to become unmanageable. Factors affecting the size of the area are geographic configuration, the asymmetric attacks expected, and the density and diversity of traffic. The size of a Naval VTS area would be adjustable and could be altered as the situation develops.

Traffic organization. To prevent dangerous traffic situations and to provide for the efficient movement of vessels, traffic in the Naval VTS area must be organized. Traffic organization can be achieved by a combination of traffic organization and management techniques.¹³ These include geographical division to separate traffic streams, time separation to give a vessel exclusive use or a restricted passage in the Naval VTS area (or subareas thereof) for a given time, and distance separation between vessels to minimize the cascading effects of harassment or attack. To minimize their effect on the cargo volume transported through the Naval VTS area, planning is required—a scheduling problem for which an algorithm has already been prepared.¹⁴

Naval VTS units. In deciding the number and location of the Naval VTS units to which ships will be requested to report, the size, traffic density, and the geographical configuration of the Naval VTS area must be considered. The key technical factor is the relationship of the radar and communication ranges of the units to the surveillance and communication requirements of the area. A good match is needed, as the quality of accident prevention depends on the units’ capability to detect developing situations and their ability to give timely warnings.

Communication procedures. These are needed for prearrival information, entry of vessels into the Naval VTS area, transit, and departure. Depending on the local situation, other communication arrangements, such as for vessels in berths and at anchor, may be needed as well.¹⁵ These procedures should stipulate what communications are required and which frequencies should be monitored.

Emergency procedures. These are needed to deal with incidents that may result from the risks present in the Naval VTS area. These procedures may include alerting the Maritime Rescue Co-ordination Center, promulgating information on the incident to vessels in the Naval VTS area, and restricting traffic. Multiple communications frequencies would be advisable: one for emergencies, a second for standard position checks, and a third on which transiting vessels report suspicious activity. How to deal with high-threat situations with low response times would require advance consideration. In addition, the advantages and disadvantages of having merchant ships restrict or cease transmissions of signals like AIS should be weighed.

Assembly areas. These may be designated in the Naval VTS area for emergencies, cross-traffic, convoy operations, and so on. When feasible, assembly areas should be situated where the likelihood of asymmetric attacks is remote and disruption of traffic flow is minimal. Assembly areas would have to be large enough to hold all ships expected.

Finally, to gain the cooperation of the merchant shipping industry, the coordinates of the Naval VTS area, the services it would provide, and its reporting procedures would be promulgated using the World-Wide Navigational Warning Service. The wording of this notice would require careful thought, so as not to raise concern needlessly in the shipping industry. 

An Example

Consider the following scenario: terrorists block the narrow Strait of Malacca by sinking a very large crude carrier by causing a deliberate collision with a hijacked 25,000-deadweight-ton (dwt.), kerosene-laden product tanker. The collision and the following inferno raise international concern and cause shipping companies to divert their ships through the Lombok and Sunda straits. In the expectation of other terrorist attacks on shipping in the Indonesian archipelago, a multinational maritime force is deployed to conduct MSO in the Java Sea. The Sunda Strait, being the shortest diversion for ships up to 100,000 dwt., becomes heavily used, and fears grow that a similar terrorist attack might occur there (see the map).¹⁶

In response, Naval VTS is activated in the Sunda Strait. The site where most congestion is expected and that is most vulnerable to deliberate collisions is the passage between Sumatra and Java, where the small island of Pulau Sangiang lies; this zone needs radar surveillance and must be included in the Naval VTS area. There are no existing VTS centers in the Sunda Strait, and according to the sailing directions there is only one track through the risk area.¹⁷ To reduce liability and gain the cooperation of the merchant shipping industry, this track is endorsed.

This decision excludes the use of geographic-division traffic-organization techniques. The deliberate ramming in the Malacca Strait had been possible because of the poor maneuvering qualities of the victim, a large tanker. Naval VTS can apply time-separation techniques to enhance the safety of such ships in the Sunda Strait—for example, giving all tankers over 60,000 dwt. going in the same direction the exclusive use of the risk area for a certain time. This prevents the dangerous situations with more maneuverable vessels (like the hijacked product tanker) and minimizes the time the larger participating tankers are exposed. Terrorists, however, can be expected to adapt their modus operandi as their targets become harder to attack. In anticipation of such changes, Naval VTS can apply distance separation, further contributing to the prevention of dangerous maritime situations and minimizing cascading effects to ship traffic in case of attack.

The risk area stretches approximately 22 nautical miles. Radar surveillance of this area is achieved by two Naval VTS units afloat, embarked on chartered civilian ships, one in the north and one in the south as depicted in the map. Vessels are requested to report to and maintain very-high-frequency (VHF) radio watch with the nearer of these units thirty minutes prior to entering the risk area. The areas of responsibility of these two units overlap along a line drawn from Java to Sumatra, over Pulau Sangiang. At this point participating vessels shift their reports and VHF watch to the other unit.

As some ninety ships a day are expected to be diverted through the Sunda Strait, time separation could cause severe congestion in the approaches; in addition, assembly areas cannot be used, due to the threat of deliberate collisions. Therefore, planning of vessel movements is imposed.¹⁸ To obtain the necessary data, the Naval VTS organization—that is, the Naval VTS commander—requests vessels to send prearrival reports confirming their participation, as soon as practicable. Position updates are also requested, at prescribed times and locations. The Naval VTS commander intends, if traffic flow without congestion cannot be achieved by planning, to give priority to ships in the northern approaches, as maneuvering space there is restricted by islands, reefs, rocks, oil fields, and shallows exposed at low tide.

Naval VTS activated in the Sunda Strait in this scenario enhances the safety of merchant shipping without drawing upon military assets. Participation is seen as a matter of common sense and, having been properly announced, is recommended by the various maritime-industry bodies. No liability is assumed, as Naval VTS participation is voluntary and participation does not compromise the responsibility or authority of masters for the safe navigation and handling of their ships.

Closing the Resource Gap

The foregoing introduction to, and outline for implementation of, the Naval VTS concept clearly illustrates how, by structuring and monitoring vessel traffic, it could enhance the safety of merchant shipping and improve the effectiveness of military activity. To minimize liability, participation in Naval VTS would have to be voluntary. This has the disadvantage that not all vessels in the Naval VTS area might cooperate, which could cause irregularities in traffic flow. These irregularities, however, would affect safety only minimally—sound traffic organization and direct interaction with participating vessels in critical zones should provide enough robustness.

In addition, Naval VTS could contribute to the international MDA security effort and through close liaison with intelligence it could make a significant contribution to the detection, identification, classification, and monitoring of possible threats. It could also be of use in other situations where vessel traffic needs to be managed quickly, such as in disaster areas.

Naval VTS has the potential to close the significant gap between the resources required for MSO and the resources available to violent nonstate actors. As such it merits further investigation and elaboration. Naval VTS tactics, techniques, and procedures would need to be developed into guidance and doctrine for Naval VTS support in maritime security operations. In addition, simulations, training, and exercises will be needed to improve procedures and gain experience and insight in the possibilities and limitations of Naval VTS.

Endnotes

1. Maritime security operations are military operations other than war conducted to ensure freedom of navigation, the flow of commerce, and the protection of the ocean.
2. NCAGS procedures support real-time monitoring and interaction of vessel traffic poorly, and traffic organization not at all. See also North Atlantic Treaty Organization [NATO], The Naval Co-operation and Guidance for Shipping Manual (NCAGS), ATP-2(B).
3. Sluiman, F. J. and De Koning, Ph, H. (2010). Naval Vessel Traffic Services: Enhancing the Safety of Merchant Shipping in Maritime Security Operations, Naval War College Review, 63, 123-137, usnwc.edu.
4. Binnie, J., “UAE’s Swift hit by anti-ship missile,” Jane’s 360, 4 October 2016, janes.com; Jonathan Saul, “Gas tanker attacked near key shipping lane off Yemen,” Reuters, 26 October 2016, www.reuters.com.
5. United Nations, Review of Maritime Transport 2016 (New York: United Nations Conference of Trade and Development [UNCTAD], 2016), org.
6. Zubir, M., The Strategic Value of the Strait of Malacca (Kuala Lumpur: Maritime Institute of Malaysia, 2004); U.S. Energy Information Administration, World Oil Transit Chokepoints, November 10, 2014, eia.gov.
7. U.S. Energy Information Administration, “Oil trade off Yemen coast grew by 20% to 4.7 million barrels per day in 2014”, Today in Energy, April 23, 2015, www.eia.gov.
8. VTS traffic organization techniques were used to establish the International Recommended Transit Corridor (IRTC) in the Gulf of Aden, but in general it has not been given proper thought in connection with MSO.
9. VTS services are defined in Guidelines for Vessel Traffic Services, IMO Resolution A.857(20), adopted 27 November 1997.
10. A navigational assistance service assists the decision-making process on board.
11. See International Maritime Organization, Convention on the International Regulations for Preventing Collisions at Sea, 1972 (COLREGs), adopted 20 October 1972, entered into force 15 July 1977.
12. Standard Marine Communication Phrases (SMCP), IMO Resolution A.918(22), adopted 29 November 2001.
13. International Association of Marine Aids to Navigation and Lighthouse Authorities [IALA], IALA VTS Manual, Edition 6, June 24, 2016, p. 42, iala-aism.org.
14. Sluiman, F. J. (2017), Transit Vessel Scheduling, Naval Research Logistics, 64, 225-248, DOI: 10.1002/nav.21742.
15. Ships at anchor are very vulnerable to asymmetric attacks, but anchoring cannot always be avoided at ports in the Naval VTS area with limited quay capacities. The security of anchorage areas in the Naval VTS area therefore deserves attention.
16. The figure of 100,000 dwt. is taken from Publication 163, Sailing Directions (Enroute): Borneo, Jawa, Sulawesi, and Nusa Tenggara, National Geospatial-Intelligence Agency, Thirteenth Edition, 2015, p. 101, nga.mil/NGAPortal/MSI.Portal.
17. Ibid., pp. 101. There is also an archipelagic sea lane (ASL) through the Naval VTS area. The axis line of the ASL, however, does not indicate the deepest water or any recommended route or track.
18. A detailed example of such a planning for the Sunda Strait scenario is given in Sluiman, Transit Vessel Scheduling.