M500-1.1.6

Port radio information services - VTS, VTIS and ALRS

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Where candidates go wrong

The most common failure is treating VTS, VTIS and Port Operations Radio Service (PORTS) as interchangeable, and being unable to explain what each service actually obliges you to do as master. A second failure is not knowing where to look up the information before arrival.


The three service types

VTS — Vessel Traffic Service A fully managed service provided in high-traffic or complex ports. Three components may be provided individually or combined:

  • Information service — broadcasts of traffic, navigational hazards, weather.
  • Traffic organisation service — active sequencing, separation and movement plans.
  • Navigational assistance service — radar-assisted guidance in poor visibility.

Participation is compulsory under SOLAS V/12 for ships to which that regulation applies. As master you must report on the required working channel, comply with movement instructions, and make mandatory position reports at designated points or times. Failure to do so is not a radio issue — it is a failure of command.

VTIS — Vessel Traffic Information Service A lesser service: information is provided but the port authority does not organise traffic or issue binding instructions. You receive; you decide. The obligation on the master is to monitor the designated channel and make any required reports, but the routing and timing decisions remain entirely yours.

PORTS — Port Operations Radio Service The basic working service: port operations, berth allocation, pilotage requests. No navigational management is implied.


Distinguishing your obligations

Service Port authority instructs? Master's primary obligation
VTS Yes Comply with movement instructions; mandatory reports
VTIS No Monitor; make required reports; self-regulate
PORTS No Working communication only

At command level you must know before entering port which regime applies and on which channel, so that your passage plan and watch handover briefings reflect the correct obligations.


ALRS — Admiralty List of Radio Signals

ALRS Volume 6 (in two parts) is the primary reference for VTS and port radio information worldwide. It lists:

  • Which service category applies to each port.
  • Mandatory reporting points and the information required.
  • Working channels and watch requirements.
  • Operating hours.

Digital versions are updated via Admiralty Digital Publications or NP286 SD cards. When planning a port entry you cross-reference ALRS with the port's own NOTAMs/Port Information and any relevant Notices to Mariners. ALRS data should be regarded as baseline; always check for local supplements.


Command-level obligation

Under SOLAS V/12 the master is responsible for compliance with VTS requirements. This cannot be delegated without the watchkeeper understanding exactly what reports are due, at what waypoints, and in what format. A pre-entry briefing covering VTS obligations, reporting waypoints and the consequences of non-compliance is the mark of a competent master.

Practice questions

recallcore

What are the three components a Vessel Traffic Service may provide, and where is the master's obligation to comply with VTS derived from?

recallcore

What is the primary publication you consult to determine which radio service category applies to a port, and what specific information does it give you?

scenariocore

You are approaching a major Mediterranean port. Your officer of the watch reports that the port has a VTS and has called you on the VTS channel requesting a position report and your ETA at the outer waypoint. The OOW is unsure how much detail to give. What do you tell him, and what does this situation tell you about your pre-arrival planning?

oralcore

Tell me the difference between a VTS and a VTIS, and how that difference changes your obligations as master.

scenariostretch

You are planning a transit through a strait with a VTIS rather than a full VTS. A junior officer argues that because the service is information-only, there is no need to monitor the VTS channel continuously — the autopilot watch is sufficient. How do you respond, and what are the underlying risks if you agree with him?

Independent preparatory study aligned to the MCA Master (Yachts less than 500 GT) oral examination syllabus. Not an MCA-approved course and confers no credit toward a Certificate of Competency.