Question 1

An ARPA target is showing a CPA of 0.4nm closing at 18 knots. As Chief Mate OOW, walk through the Rule 8 requirements for any action you take.

Accepted Answer

RULE 8 — ACTION TO AVOID COLLISION — CM LEVEL ANALYSIS: Rule 8 sets the QUALITY requirements for any collision avoidance action. REQUIREMENTS: (1) Rule 8(a): "Any action taken to avoid collision shall, if the circumstances of the case admit, be taken in time to allow it to be given effect by ample sea room, with due regard to the observation of good seamanship." — DO NOT LEAVE IT LATE. Action must be taken in good time; (2) Rule 8(b): "Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit, be large enough to be readily apparent to the other vessel observing visually or by radar." — THE ACTION MUST BE BOLD AND OBVIOUS. A 5° course change is dangerous — it may not be detected by the other vessel. A 30-60° course change is clearly apparent on radar; (3) Rule 8(c): "If there is sufficient sea room, alteration of course alone may be the most effective action to avoid a close-quarters situation, provided that it is made in good time, is substantial and does not result in another close-quarters situation." — COURSE CHANGE IS OFTEN BEST IF EARLY AND LARGE; (4) Rule 8(d): "Action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance." — THE RESULT MUST BE ACTUALLY SAFE — not just a 0.5nm CPA if the wind/current may reduce it further; (5) Rule 8(e): "If necessary to avoid collision or allow more time to assess the situation, a vessel may slacken her speed or stop or reverse her engines." — SPEED REDUCTION IS AN OPTION, especially in close-quarters where alteration might create another hazard; (6) Rule 8(f): Duty not to impede — does not relieve duty to keep safe. APPLICATION TO SCENARIO: CPA 0.4nm at 18kn closing rate — close quarters risk. Take early, large course alteration (at least 30°) to starboard to open the CPA to at least 1nm. The 5° alteration problem (option B): a 5° course change at 18 knots gives very little radar trail for the other vessel to observe. The other OOW is watching a target that was on a CPA of 0.4nm — a 5° heading change shifts the CPA minimally and may not be visible on their ARPA for several minutes. Rule 8(b) specifically requires the action to be "readily apparent" — and 5° is not. The 0.2nm trigger (option C): there is no fixed COLREG definition of "close quarters" in terms of distance. Close quarters depends on the specific situation — vessel sizes, speeds, sea room, visibility. 0.4nm with a large fast vessel approaching is already potentially close quarters. Waiting until 0.2nm is dangerous because at 18 knots closing speed, 0.2nm gives only approximately 40 seconds for action. COLREG Rule 8 requires action "in time to allow it to be given effect" — not at the last possible moment. Five short blasts (option D): Rule 34(d) — five or more short blasts is the signal of doubt about another vessel's intentions. It is a SIGNAL, not a substitute for action. Sounding five blasts does not relieve the obligation to manoeuvre when action is required. After sounding five blasts, you still must take appropriate action. A vessel that sounds five blasts and then does nothing — and a collision occurs — cannot use the signal as a defence. Safe distance (Rule 8(d)): "safe distance" is subjective and context-dependent. In congested waters with poor visibility — 1nm may be minimum. In open ocean — 0.5nm may be acceptable. The CM must apply professional judgment.

Question 2

You are OOW on a 25,000 GT general cargo vessel making 12 knots in open waters. You observe a vessel displaying two black balls in a vertical line and two all-round red lights at night. What is this vessel and what are your obligations?

Accepted Answer

NUC VESSEL — CM RESPONSE: The vessel displaying TWO BLACK BALLS (day) / TWO ALL-ROUND RED LIGHTS vertical (night) is a NOT UNDER COMMAND (NUC) vessel. COLREG Rule 27(a): "A vessel not under command shall exhibit two all-round red lights in a vertical line where they can best be seen; two balls or similar shapes in a vertical line where they can best be seen." DEFINITION (Rule 3(f)): "Not under command means a vessel which through some exceptional circumstance is unable to manoeuvre as required by these rules and is therefore unable to keep out of the way of another vessel." Typical causes: main engine failure; steering gear failure; loss of power. YOUR OBLIGATIONS: (1) YOUR VESSEL MUST KEEP CLEAR: a NUC vessel cannot take avoiding action. The NUC display is an advisory signal — YOU must manoeuvre. Rule 18(a): "A power-driven vessel underway shall keep out of the way of: a vessel not under command." (2) EARLY AND SUBSTANTIAL ACTION: Rule 16 — "Every vessel which is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear." (3) MONITOR CLOSELY: even if CPA is safe, continue to monitor. A NUC vessel may drift with current or alter if she partially regains power; (4) VHF: brief communication to confirm her situation and intentions may be appropriate; (5) CALL MASTER: at night in a crossing or overtaking situation with a NUC vessel — consider calling master. The situation could deteriorate rapidly if she is drifting; (6) ADDITIONAL LIGHT: if the NUC vessel is also making way — she shows sidelights in addition to the red lights. Rule 18 hierarchy (give-way order): A power-driven vessel underway keeps clear of: NUC; RAM; CBD; sailing vessel; vessel fishing. Among themselves: overtaking gives way to overtaken; port gives way to starboard (crossing); head-on both alter to starboard. NUC vs anchored (option C): two black balls in a vertical line = NUC. ONE black ball = anchored (Rule 30). A critical distinction. An anchored vessel also displays a white anchor light (all-round), not red lights. Two ALL-ROUND RED LIGHTS are the NUC night signal. Rule 18 hierarchy rationale: a NUC vessel genuinely cannot manoeuvre. Expecting them to give way is dangerous and pointless — they cannot comply. The rules therefore place the burden on vessels that CAN manoeuvre to stay clear of those that CANNOT. The principle of reduced manoeuvrability. NUC making way: a vessel with engine failure but still moving (from momentum or tidal current) must still display sidelights (green/red) because she is making way. This helps other vessels assess the aspect. The NUC signals are ADDITIONAL to normal lights when making way. Master call decision: at night, with a NUC vessel ahead, in confined waters, or when CPA is under 1nm — the master should be called. The NUC vessel may be drifting in an unpredictable direction. The situation has greater uncertainty than normal traffic.

Question 3

You observe a vessel displaying a ball, diamond, ball in a vertical line and red-white-red all-round lights. What type of vessel is this and what lights does she show at night when making way?

Accepted Answer

RAM VESSEL — IDENTIFICATION AND LIGHTS: The vessel displaying BALL-DIAMOND-BALL (day) and ALL-ROUND RED-WHITE-RED (night) is RESTRICTED IN ABILITY TO MANOEUVRE (RAM). COLREG Rule 27(b): "A vessel restricted in her ability to manoeuvre, except a vessel engaged in mineclearing operations, shall exhibit: three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white; three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond." WHEN MAKING WAY ADDITIONALLY: masthead light(s), sidelights, and sternlight — in addition to the RAM signals. TYPICAL RAM VESSELS: a dredger; a vessel engaged in surveying or hydrographic work; a vessel engaged in buoy laying operations; a cable-laying vessel; a vessel conducting replenishment at sea (RAS); a tug engaged in a towing operation that severely restricts her ability to manoeuvre; a vessel engaged in diving operations; a minelayer. YOUR OBLIGATIONS: Rule 18(b): "A power-driven vessel underway shall keep out of the way of a vessel restricted in her ability to manoeuvre." Your vessel must keep clear. A RAM vessel with obstruction on one side: Rule 27(d) — if the vessel's ability to manoeuvre is restricted due to work on one side, she shows additional lights/shapes to indicate the safe side to pass. Day signals — fishing vs RAM (option B): fishing vessels under Rule 26 show a CONE (apex down) by day and ALL-ROUND GREEN over RED lights at night. The Rule 27 RAM signals (ball-diamond-ball / red-white-red) are completely distinct. This is a frequently confused pair in oral exams. Rule 18 hierarchy continuation: power-driven vessels keep clear of: NUC, RAM, CBD, fishing, sailing. RAM is above CBD in the hierarchy — a power-driven vessel gives way to RAM. However, RAM does NOT take precedence over a vessel not under command. NUC has the same or higher priority. Practical RAM examples examiners probe: (1) Cable-laying vessel — significant RAM; crosses traffic schemes; (2) RAS (Replenishment At Sea) — the supply vessel and the warship being replenished both display RAM; (3) Dredger with pipe over the side — additionally marks the side where passing is dangerous (Rule 27(d)); (4) Diving support vessel — Rule 27(e) additional signals; (5) Minesweeper — Rule 27(f) additional three all-round green lights, one at each end of the sweep. RAM on one side additional signals: Rule 27(d) — when the work creates a hazard on one side, the RAM vessel shows: two additional all-round red lights on the side of the obstruction and two all-round green lights on the safe-to-pass side. A dredger with a suction pipe extending to starboard would show: red-red to starboard, green-green to port.