Question 1

A sailing vessel and a power-driven vessel are approaching each other in restricted visibility, detected only by radar. Does Rule 18's general hierarchy (power-driven keeps clear of sailing) apply in this scenario?

Accepted Answer

No — Rule 18 sits within Section II ("Conduct of Vessels in Sight of One Another") and does not apply when vessels are not in sight of one another; in restricted visibility, both vessels are instead governed by Rule 19, which applies a different framework (safe speed, engines ready, and the alteration-avoidance guidance in Rule 19(d)) without reference to vessel category hierarchy This mirrors the earlier point about Rule 15 — the entire "in sight of one another" framework (Rules 11-18, including the category hierarchy of Rule 18) does not apply in restricted visibility without visual contact; Rule 19 applies instead, and it does not distinguish between vessel categories in the way Rule 18 does.

Question 2

Rule 5 (Look-out) requires every vessel at all times to maintain a proper look-out by sight and hearing, as well as by all available means appropriate in the prevailing circumstances and conditions — and this duty applies even when the vessel is at anchor in a busy anchorage.

Accepted Answer

True True. Rule 5 applies 'at all times' and to 'every vessel'. A vessel at anchor in a busy anchorage still needs an effective look-out to detect drifting vessels, dragging anchors, or approaching traffic that may pose a risk of collision or contact.

Question 3

Under Rule 6 (Safe Speed), a vessel fitted with a fully operational radar and ARPA never needs to reduce speed in restricted visibility, because the equipment guarantees early detection of other vessels.

Accepted Answer

False False. Rule 6 explicitly lists radar capability as one factor to consider, but also requires accounting for the state of visibility, traffic density, manoeuvrability, and the limitations of radar (range scale, sea/rain clutter, blind sectors). Even a vessel with excellent radar must proceed at a speed that allows proper and effective action to avoid collision and to be stopped within a distance appropriate to the prevailing circumstances.