DWO Navigation Rules 3 — Questions and Answers
Question 1: Which factor does NOT determine whether a vessel is 'underway' under the Navigation Rules?
- Not at anchor
- Not made fast to the shore
- Not aground
- Moving through the water (Correct answer)
Correct answer: Moving through the water
Rule 3 defines 'underway' as not at anchor, not made fast to shore, and not aground — actual movement through the water is not required.
Question 2: What is the required arc of visibility for a vessel's masthead light?
- 112.5 degrees
- 225 degrees (Correct answer)
- 135 degrees
- 360 degrees
Correct answer: 225 degrees
Rule 21 specifies that a masthead light shows an unbroken white light over an arc of 225 degrees.
Question 3: In restricted visibility, a power-driven vessel making way through the water shall sound:
- One prolonged blast at intervals of not more than 2 minutes
- Two prolonged blasts at intervals of not more than 2 minutes
- One prolonged blast at intervals of not more than 1 minute (Correct answer)
- Two short blasts every 2 minutes
Correct answer: One prolonged blast at intervals of not more than 1 minute
Rule 35(a) requires a power-driven vessel making way to sound one prolonged blast at intervals of not more than 2 minutes.
Question 4: A vessel constrained by her draft shall exhibit which lights at night?
- Three red lights in a vertical line
- Two red lights in a vertical line
- Three all-round red lights in a vertical line (Correct answer)
- One red over one white over one red in a vertical line
Correct answer: Three all-round red lights in a vertical line
Rule 28 requires a vessel constrained by her draft to show three all-round red lights in a vertical line.
Question 5: Under Rule 10, which vessel shall not impede the safe passage of a vessel following a traffic separation scheme?
- All vessels in the separation zone
- A vessel crossing a traffic lane (Correct answer)
- A vessel engaged in fishing within the scheme
- A vessel under 20 meters
Correct answer: A vessel crossing a traffic lane
Rule 10(c) states that a vessel crossing traffic lanes shall not impede the passage of vessels following those lanes.
Question 6: What does one short blast on the whistle indicate under Inland Rules when vessels are in sight of one another?
- I am altering my course to port
- I intend to leave the other vessel on my port side
- I am altering my course to starboard (Correct answer)
- I am operating in reverse
Correct answer: I am altering my course to starboard
Under Inland Rule 34, one short blast means 'I intend to leave you on my port side' (i.e., altering course to starboard).
Question 7: A vessel engaged in pilotage duty displays which dayshape?
- A ball
- No special dayshape (Correct answer)
- A cylinder
- A diamond
Correct answer: No special dayshape
Rule 29 grants pilot vessels only light requirements; no special dayshape is prescribed for a pilot vessel on duty.
DWO Navigation Rules 3
Which factor does NOT determine whether a vessel is 'underway' under the Navigation Rules?