You are in restricted visibility. You detect a vessel on radar bearing 045°, range 3nm, CPA 0.8nm, TCPA 12 minutes. It is a sailing vessel. Do the sailing vessel crossing rules (Rule 12/18) apply?

A. RULE 19 vs RULES 11-18 — THE CRITICAL DISTINCTION: ANSWER: NO — the sailing vessel crossing rules (Rules 12 and 18) do NOT apply in this situation. KEY PRINCIPLE: Rules 11-18 apply only to vessels "in sight of one another" — this means VISUALLY in sight (Rule 3(k)). A radar contact in restricted visibility is NOT "in sight" for COLREG purposes. THEREFORE: in restricted visibility, Rule 19 applies to ALL encounters regardless of vessel type. You do not give way to the sailing vessel under Rule 18; the sailing vessel does not have right of way over you. Both vessels must: (a) Proceed at safe speed; (b) Take action to avoid collision — specifically as per Rule 19(d) if either determines a close-quarters situation is developing; PRACTICAL APPLICATION: CPA 0.8nm in restricted visibility — this may be acceptable in open ocean, but near the UK coast or in congested areas 0.8nm could still be too close given vessel sizes and stopping distances. Assess whether a close-quarters situation is developing. If so: take avoiding action now. FOR THE SAILING VESSEL: the sailing vessel must also apply Rule 19 — it cannot rely on its Rule 18 priority in fog. Both vessels must independently avoid the situation.

B. Rule 18 (power vessel gives way to sailing vessel) applies in all circumstances, including restricted visibility. Your vessel must take avoiding action regardless of the fog.

C. In restricted visibility with radar detection only, a 0.8nm CPA is automatically a safe CPA. No avoiding action is required unless CPA drops below 0.5nm.

D. In restricted visibility, the OOW should contact the sailing vessel by VHF to agree which COLREG rules will apply — Rules 11-18 or Rule 19.

A. COLREG RULE 19 — CONDUCT IN RESTRICTED VISIBILITY: Rule 19 applies to ANY vessel not in sight of another. Key requirements: (1) RULE 19(b) — SAFE SPEED: proceed at a safe speed adapted to prevailing circumstances and restricted visibility. The vessel must be able to take proper and effective action to avoid collision, and stop within an appropriate distance; (2) RULE 19(c) — RADAR: have due regard to prevailing circumstances, including the limitations of radar equipment; (3) RULE 19(d) — RADAR-ONLY CONTACT: a vessel that detects by radar only another vessel shall determine if a close-quarters situation is developing. If so — take early, substantial avoiding action: (i) an alteration of course to port for a vessel forward of the beam is to be AVOIDED (except when overtaking); (ii) avoid altering course toward a vessel abeam or abaft the beam; (4) RULE 19(e) — SOUND SIGNAL WARNING: if a sound signal is heard apparently forward of the beam and its vessel cannot be seen — reduce to minimum speed or stop. Take all way off if necessary; (5) RULE 35 — FOG SIGNALS: one prolonged blast (4-6 seconds) every 2 minutes when underway making way. Two prolonged blasts (2-second interval) every 2 minutes when underway but stopped. RULE 19 DOES NOT APPLY RULES 11-18 (in-sight rules). There is no give-way/stand-on in restricted visibility. All vessels take action to avoid collision.

B. Rule 19 suspends all other COLREG rules in fog. No vessel has right of way in fog, and any vessel may alter course in any direction to avoid collision.

C. Rule 19 requires vessels in restricted visibility to stop and anchor until visibility improves to at least 1nm before proceeding.

D. In restricted visibility, the stand-on vessel (Rule 17) must maintain course and speed even in fog. Rule 19 only applies to give-way vessels.

A. RULE 35 FOG SIGNALS — CORRECT SIGNALS: (a) POWER VESSEL UNDERWAY MAKING WAY (Rule 35a): ONE prolonged blast (4-6 seconds) — every 2 minutes; (b) POWER VESSEL UNDERWAY BUT STOPPED (Rule 35b): TWO prolonged blasts with 2-second interval — every 2 minutes; (c) VESSEL AT ANCHOR (Rule 35g): rapid ringing of bell for approximately 5 seconds — every 1 minute. Vessels of 100m+ ALSO sound a gong aft for 5 seconds after the bell. A vessel at anchor MAY ALSO sound "short-long-short" (Morse R —. — .) as a warning to approaching vessels; (d) VESSEL AGROUND (Rule 35h): three separate bell strokes, THEN rapid ringing of bell for 5 seconds, THEN three separate bell strokes — every 1 minute. This sequence distinguishes a vessel aground from one merely at anchor. ADDITIONAL SIGNALS: sailing vessel under sail — Rule 35c: one prolonged + two short blasts every 2 minutes (this same signal is also used by vessels restricted in ability to manoeuvre, constrained by draught, not under command, and towing/being towed — Rule 35d/e); pilot vessel — Rule 35g: normal fog signal + four short blasts as identity signal.

B. All vessels in restricted visibility sound one prolonged blast every 2 minutes regardless of their status. Rule 35 makes no distinction between underway, stopped, or at anchor.

C. A vessel at anchor does not need to sound fog signals provided she has all-round white anchor lights displayed and is monitoring VHF Ch 16.

D. Two short blasts is the correct fog signal for a power vessel underway making way. One prolonged blast is used only by sailing vessels.