AB Navigation & Watchstanding 5 — Questions and Answers
Question 1: A vessel displaying a black ball forward during daylight hours is indicating that she is:
- Not under command
- At anchor (Correct answer)
- Constrained by her draft
- Restricted in her ability to maneuver
Correct answer: At anchor
COLREGS Rule 30 requires a vessel at anchor to display one black ball in the forward part of the vessel during daylight hours.
Question 2: What is the meaning of the term 'deviation' as used in compass adjustment?
- The difference between true north and magnetic north caused by the Earth's magnetic field
- The error of the magnetic compass caused by the ship's own magnetic fields (Correct answer)
- The angular difference between the gyrocompass heading and the true heading
- The angle between the vessel's course and the direction of leeway
Correct answer: The error of the magnetic compass caused by the ship's own magnetic fields
Deviation is the error in a magnetic compass caused by the vessel's own iron, steel, and electrical equipment — it changes with the ship's heading.
Question 3: During a watch handover, which information is essential to pass to the relieving officer?
- The cook's meal schedule and port agent contact details
- Course, speed, position, traffic situation, weather, and any outstanding orders (Correct answer)
- Only the current radar settings and autopilot mode
- The vessel's draft and last drydock date
Correct answer: Course, speed, position, traffic situation, weather, and any outstanding orders
A proper watch handover must include course, speed, position, traffic in the area, weather, visibility, standing orders, and any abnormal conditions or tasks in progress.
Question 4: Under COLREGS Rule 9, a vessel of less than 20 meters in length navigating in a narrow channel shall:
- Always sound two short blasts before entering the channel
- Not impede the passage of a vessel that can only safely navigate within the channel (Correct answer)
- Proceed only during daylight hours without special permission
- Anchor in the center of the channel and wait for traffic to clear
Correct answer: Not impede the passage of a vessel that can only safely navigate within the channel
Rule 9 requires small vessels (under 20 m) and sailing vessels not to impede the passage of vessels that can only safely navigate within a narrow channel.
Question 5: When a helmsman is steering by gyrocompass and the order 'meet her' is given, the helmsman should:
- Come to an all-stop until new orders are received
- Apply opposite rudder to check the vessel's swing and steady on the new heading (Correct answer)
- Increase rudder angle to accelerate the turn
- Return the rudder to amidships immediately and hold course
Correct answer: Apply opposite rudder to check the vessel's swing and steady on the new heading
'Meet her' means apply counter-rudder to stop the swing so the vessel steadies on or near the intended heading without overshooting.
Question 6: A light that is described in the Light List as 'Fl(2) 10s 15m 12M' means the light:
- Flashes twice every 10 seconds, is 15 meters above water, and is visible 12 nautical miles (Correct answer)
- Flashes 2 times per minute for 10 seconds, height 15 feet, range 12 km
- Has a 10-second period with 2 occultations, 15-meter range, and a 12-meter tower
- Rotates twice every 15 seconds, is 10 meters high, and has a 12-mile range in fog
Correct answer: Flashes twice every 10 seconds, is 15 meters above water, and is visible 12 nautical miles
Light List notation: Fl(2) = group flashing 2 times; 10s = period of 10 seconds; 15m = elevation above MHWS in meters; 12M = nominal range in nautical miles.
Question 7: When a vessel is described as making 'leeway,' it means the vessel is:
- Traveling faster than her charted speed due to a following current
- Being pushed sideways downwind from her intended course by wind pressure (Correct answer)
- Taking on water through a lee-side scupper
- Anchoring on the lee side of an island for shelter
Correct answer: Being pushed sideways downwind from her intended course by wind pressure
Leeway is the lateral drift of a vessel downwind from her intended course, caused by wind acting on the hull and superstructure above water.
AB Navigation & Watchstanding 5
A vessel displaying a black ball forward during daylight hours is indicating that she is: