What YOU need to know about working with VTS

01 Oct 2022 The Navigator

As a navigator, you will have learned about, and used, vessel traffic services – VTS. In this article, Jillian Carson-Jackson takes a look at how they can help you ensure a safer, more efficient time at sea – and explains what’s different from what you may have read in our previous Navigator on this topic.

Since the 1940’s, the use of VHF voice radio, combined with radar and other sensors, has been used to support safe, efficient and pollution-free transits. To understand how to make the most of VTS, you first need to understand the regulatory structure that it is based on. Additionally, it is good to have solid knowledge about the technology used in VTS, and how to operate it, including voice procedures.

A good place to start is to consult SOLAS Chapter 5, Regulation 12. This identifies where – and why – a VTS may be implemented and is supported by IMO resolutions, guidelines and circulars. The importance of VTS is also referenced in the Manila Amendments to the STCW 1978 Convention.

Regulatory structure
In essence, a VTS is implemented in any port or coastal area where a risk assessment has determined a need for it. The establishment of VTS is dependent on national law and relevant international conventions, and considers factors such as the volume of traffic, degree of risk and geographical and environmental conditions. It is not just based on the number of vessel movements – sometimes, there may be VTS implemented in a port with less traffic than another port which does not have VTS, based on environmental concerns, for example. Information on the VTS will be shared in appropriate maritime publications, as well as port-user handbooks and websites.

According to SOLAS Chapter 5, Regulation 12, VTS can be made compulsory within the territorial sea, and it can also be established in association with other IMO regulations. It may also be established beyond the territorial seas of a coastal state to provide information and advice on the basis of voluntary participation.

In 2021, the IMO approved a revised resolution on VTS – IMO A.1158(32). This new guideline replaces the previous IMO A.857(20). So, if you thought you knew all about VTS because you were familiar with IMO A.857(20), beware! While, at its core VTS remains the same, some aspects have definitely changed.

One such change can be found in the terminology surrounding VTS. While the definition of VTS remains essentially the same, there have been revisions made to the ‘authorities’ related to VTS. Check out the box opposite for the latest definitions.

The resolution also highlights the qualification and training of VTS, noting that VTS professionals are a major factor in its operation. VTS personnel are only considered competent when appropriately trained and qualified for their VTS duties. This includes a detailed training programme with on-the-job teaching, periodic assessments and revalidation of training.

Purpose of VTS
We all know that VTS contributes to the safety of life at sea. It improves the safety and efficiency of navigation and supports the protection of the environment within a VTS area by mitigating the development.

of unsafe situations. So, how is this done? VTS provides timely and relevant information and communications between ship, shore, and other shore agencies – information that helps you, as a navigator, to do your job. This can include information on other ships, maritime safety data, any limitations or restrictions in place and more.

VTS has access to some great equipment to help monitor the VTS area (and usually a bit beyond the limits of the area). By using these tools, and additional information from allied services, VTS monitors and manages ship traffic to keep the waterway safe and support efficient ship movements. This can include planning movements in advance, organising water space allocation, using traffic clearances and providing route advice, as well as ensuring compliance with regulatory provisions (where they are empowered to do so).

Thanks to all the information they have, and the monitoring tools available, VTS can also respond to developing unsafe situations. For example, it can provide support to a ship that is unsure of its position, notify a ship when it is deviating from the planned route, provide emergency responses, support emergency services… you get the idea.

Technical tools
The digitalisation of the maritime environment means that VTS tools are getting more and more sophisticated. As a navigator, you will almost certainly have communicated with a VTS using VHF, but you may also have checked out information on a website or exchanged information by email or other digital means. VTS uses different tools to monitor the waterway – not only the ships, but also other aspects, such as the state of the tide and tidal stream, weather, port operations such as diving, dredging and even yacht races. Input from the different sensors is displayed in the VTS centre and presented through what is known as a Decision Support Tool, or ‘DST’. A DST can combine radar, AIS, CCTV, tidal data, under-keel clearance systems and more.

In addition to all the tools to monitor the waterway, VTS also has tools to connect with other allied services to support safe and secure operations. VTS is an important information hub for the port.

Operational procedures
Just like the navigator onboard ship, the VTS operator has their own set of operational procedures. These include agreed parameters for when different activities can take place, minimum separation distances or time separations for movements and so much more.


Some of the terms and definitions used in connection with vessel traffic services, as set out in IMO Res A-1158(32):

Vessel traffic services – services implemented by a Government with the capability to interact with vessel traffic and respond to developing stations within a VTS area

Competent authority – the entity made responsible by the Government for vessel traffic services

VTS provider – the organization or entity authorized by the Government or competent authority to provide vessel traffic services

VTS area – the delineated, formally declared area for which the VTS provide is authorised to deliver vessel traffic services

VTS personnel – persons performing tasks associated with vessel traffic services, trained in vessel traffic servies operations and appropriately qualified

A key element for communication with the VTS is the VHF voice procedures. VTS professionals are taught specific voice procedures to ensure clear and unambiguous communications using the same Standard Marine Communication Phrases (SMCP) that navigators are taught. VTS use message markers specifically to help with the communications, noting the critical and often time-sensitive nature of their communications. Message markers can really help focus the communications. For example, when asking for confirmation of the vessel’s draft, the VTSO would say ‘QUESTION: what is your maximum draft?’ To help support the communications, IALA has developed Guideline 1132 on VTS Voice Communications and Phraseology. 

If you are interested in anything related to VTS, go to the IALA website and type ‘VTS’ into the search bar – you will find lots of great information there!