Practice Test Geeks(VTS) Vessel Traffic Services Operator Exam Practice Test
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Navigation Systems Flashcards

7 cards from real VTS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Navigation Systems flashcards as text

  1. What is the purpose of a Vessel Traffic Service (VTS) radar's 'gain' control?

    Answer: To adjust the sensitivity of the radar receiver to detect weaker targets

    Radar gain controls receiver sensitivity; increasing gain detects weaker or more distant targets, while reducing gain can eliminate noise and clutter.

  2. A vessel's AIS is transmitting a static draught of 8 meters, but the navigable channel has a controlling depth of 9 meters. What action should the VTS operator take?

    Answer: Monitor the vessel and verify the charted controlling depth against current tidal conditions before advising

    The operator must account for tidal state to determine actual underkeel clearance before determining whether the transit is safe and what advice to provide.

  3. What is 'sea clutter' on a radar display, and which control is used to reduce it?

    Answer: Returns from waves near the vessel, reduced using the STC (Sensitivity Time Control) or sea clutter control

    Sea clutter is caused by radar energy reflecting off wave surfaces close to the antenna, and the STC control progressively reduces gain at short ranges to suppress it.

  4. Under 33 CFR Part 161, which vessels are generally required to participate in a U.S. Vessel Traffic Service?

    Answer: Power-driven vessels of 40 meters or more in length, certain towing vessels, and vessels carrying hazardous cargo

    33 CFR Part 161 specifies that VTS participation is mandatory for power-driven vessels ≥40 meters, certain towing vessels, and vessels carrying hazardous materials in designated VTS areas.

  5. What is the function of a 'waypoint' in electronic navigation systems used by vessels reporting to VTS?

    Answer: A predetermined geographic position used as a reference point along a planned route

    A waypoint is a specific latitude/longitude position programmed into a navigation system to define the intended route, allowing automatic course guidance.

  6. How does AIS Class A differ from AIS Class B in reporting interval during transit at speed?

    Answer: Class A reports every 2–10 seconds depending on speed; Class B reports every 30 seconds

    Class A AIS (fitted on SOLAS vessels) reports position every 2–10 seconds when underway at speed, while Class B (recreational/smaller vessels) reports every 30 seconds.

  7. What navigational hazard does a 'squat effect' present to a vessel transiting a shallow or confined channel, and why must VTS operators be aware of it?

    Answer: Squat causes a vessel to sink lower in the water at speed, reducing underkeel clearance and increasing grounding risk

    Squat effect occurs when a vessel's speed through shallow water causes it to sink lower than its static draught, potentially grounding even if static calculations show adequate clearance.