VTS Traffic Management and Navigation 5 — Questions and Answers
Question 1: Under IALA recommendations for VTS, which service level involves the VTS providing navigational assistance to a vessel upon request or on the operator's own initiative?
- Information Service (INS)
- Traffic Organization Service (TOS)
- Navigational Assistance Service (NAS) (Correct answer)
- Port Management Information Service (PMIS)
Correct answer: Navigational Assistance Service (NAS)
Navigational Assistance Service (NAS) is the IALA VTS service level where the operator actively assists vessels with navigation, particularly in difficult circumstances.
Question 2: A VTS operator observes via radar that a vessel's echo has disappeared in a rain clutter area near a rocky shoal. What is the most prudent immediate action?
- Assume the vessel transited safely and wait for its next report
- Adjust the radar's STC (Sensitivity Time Control) to reduce clutter and attempt to reacquire the target, then contact the vessel (Correct answer)
- Declare a MAYDAY immediately
- Note the disappearance in the log and continue monitoring other traffic
Correct answer: Adjust the radar's STC (Sensitivity Time Control) to reduce clutter and attempt to reacquire the target, then contact the vessel
Adjusting STC to reduce rain clutter to attempt target reacquisition and simultaneously contacting the vessel is the appropriate initial response to an unexplained echo loss.
Question 3: A VTS authority issues a 'recommended route' to a vessel. What is the vessel master's legal obligation regarding this recommendation?
- The master must comply or face immediate detention
- The master should follow the recommendation but retains ultimate responsibility for safe navigation (Correct answer)
- The recommendation carries no weight and may be ignored
- The master must comply only if the recommendation is issued in writing
Correct answer: The master should follow the recommendation but retains ultimate responsibility for safe navigation
In most VTS regimes, recommended routes are advisory; the vessel master retains command and ultimate responsibility for safe navigation.
Question 4: When a VTS operator uses dead reckoning to project a vessel's future position, which three elements are required?
- Last known position, speed over ground, and heading (Correct answer)
- GPS fix, chart datum, and tidal stream
- AIS class, vessel draft, and cargo manifest
- Port of departure, ETA, and fuel capacity
Correct answer: Last known position, speed over ground, and heading
Dead reckoning requires a known starting position, speed, and course to project where a vessel will be at a future time.
Question 5: A vessel operating in a VTS area declares a MAYDAY. After relaying the MAYDAY to the Coast Guard, the VTS operator should:
- Cease all other duties to focus solely on the distress vessel
- Continue normal traffic management while providing assistance as directed by the rescue coordination center (Correct answer)
- Transfer all VTS responsibilities to the Coast Guard for the duration of the distress
- Immediately broadcast a SECURITE for all vessels in the area
Correct answer: Continue normal traffic management while providing assistance as directed by the rescue coordination center
VTS operators maintain normal traffic management duties while supporting the rescue coordination center's instructions, as both functions are essential during a distress situation.
Question 6: What is 'traffic separation' in the context of a VTS-managed waterway?
- The physical buoying of lanes using floating marks only
- The organizational measure directing opposing streams of traffic into separate lanes to reduce head-on collision risk (Correct answer)
- The scheduling of vessel departures to prevent congestion
- The assignment of different radio channels to inbound and outbound vessels
Correct answer: The organizational measure directing opposing streams of traffic into separate lanes to reduce head-on collision risk
Traffic separation organizes opposing vessel traffic streams into defined lanes, reducing the risk of head-on encounters in confined or busy waterways.
Question 7: A vessel reports its ETA to the VTS as 1430 local time, but radar tracking indicates it will arrive significantly earlier based on its current speed. The VTS operator's best action is to:
- Accept the vessel's reported ETA without question
- Contact the vessel to confirm its speed and revise the ETA, then coordinate berth and traffic accordingly (Correct answer)
- Notify the port authority of the discrepancy and take no further action
- Instruct the vessel to reduce speed to match its reported ETA
Correct answer: Contact the vessel to confirm its speed and revise the ETA, then coordinate berth and traffic accordingly
Confirming and correcting the ETA with the vessel ensures accurate berth coordination and traffic management planning for all stakeholders.
VTS Traffic Management and Navigation 5
Under IALA recommendations for VTS, which service level involves the VTS providing navigational assistance to a vessel upon request or on the operator's own initiative?