AB Navigation & Watchstanding 2 — Questions and Answers
Question 1: When standing a proper lookout at night, which method of viewing is most effective for detecting dim objects?
- Direct central vision focused on the object
- Off-center or peripheral vision slightly away from the object (Correct answer)
- Using binoculars continuously in all directions
- Scanning rapidly in a left-to-right sweeping motion only
Correct answer: Off-center or peripheral vision slightly away from the object
At night, rod cells in the peripheral retina are more sensitive to low light, so looking slightly off-center (eccentric viewing) reveals dim objects better than direct central vision.
Question 2: A vessel is required to proceed at a safe speed. Which factor is NOT listed under COLREGS Rule 6 for determining safe speed?
- State of visibility
- Traffic density
- The experience level of the helmsman (Correct answer)
- The maneuverability of the vessel
Correct answer: The experience level of the helmsman
COLREGS Rule 6 lists visibility, traffic density, maneuverability, and background lights as factors, but the helmsman's experience level is not included.
Question 3: You are on watch and the vessel's magnetic compass reading differs from the gyrocompass by more than 2 degrees compared to the last logged error. What should you do first?
- Immediately alter course to the magnetic compass heading
- Take a third bearing using a celestial body to resolve the discrepancy
- Report the discrepancy to the officer of the watch and note it in the log (Correct answer)
- Assume the gyrocompass is correct and disregard the magnetic compass
Correct answer: Report the discrepancy to the officer of the watch and note it in the log
Any significant change in compass error must be reported to the OOW and logged so it can be investigated; the watch officer decides the appropriate action.
Question 4: According to the International Regulations for Preventing Collisions at Sea, a vessel is considered to be 'underway' when she is:
- Moving through the water at any speed
- Not at anchor, not made fast to shore, and not aground (Correct answer)
- Operating under engine power only
- Steaming at more than 3 knots
Correct answer: Not at anchor, not made fast to shore, and not aground
COLREGS Rule 3 defines 'underway' as not at anchor, not made fast to shore, and not aground — regardless of whether the vessel is moving.
Question 5: While keeping a radar watch in restricted visibility, you detect a vessel fine on your starboard bow with a steady bearing and decreasing range. According to COLREGS, you should:
- Maintain course and speed since the other vessel is the give-way vessel
- Sound one short blast and alter course to starboard
- Reduce speed, stop, or take all way off as necessary (Correct answer)
- Immediately hard-a-port to cross astern of the contact
Correct answer: Reduce speed, stop, or take all way off as necessary
In restricted visibility, Rule 19 requires reducing speed to bare steerage, stopping, or taking all way off when a close-quarters situation may develop — normal crossing rules do not apply.
Question 6: What is the primary purpose of plotting a running fix when only one landmark is available?
- To determine the vessel's speed made good over the ground
- To obtain a position using two bearings of the same object taken at different times (Correct answer)
- To correct for leeway and current simultaneously
- To verify the accuracy of the GPS position
Correct answer: To obtain a position using two bearings of the same object taken at different times
A running fix advances an earlier bearing line along the vessel's track to cross a new bearing of the same object, yielding a position with a single landmark.
Question 7: On a vessel with a conventional rudder, when the order 'hard right rudder' is given, the bow will initially swing to the right and the stern will:
- Remain stationary due to forward momentum
- Swing to the left (port) (Correct answer)
- Swing to the right (starboard) as well
- Dip lower in the water due to increased resistance
Correct answer: Swing to the left (port)
When the rudder is put hard right, the stern kicks to port (left) as the bow swings to starboard — the ship pivots about a point roughly one-third aft of the bow.
AB Navigation & Watchstanding 2
When standing a proper lookout at night, which method of viewing is most effective for detecting dim objects?