At night you observe a vessel ahead with both masthead white lights bearing on approximately 005° True — your course is 003° True. The bearing is steady. Is this head-on and what action do you take?

A. RULE 14 — HEAD-ON SITUATION — CM ASSESSMENT: RULE 14(a): "When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, each shall alter her course to starboard so that each shall pass on the port side of the other." IDENTIFYING HEAD-ON (Rule 14(b)): "A vessel shall be deemed to be in a head-on situation when she sees another vessel ahead or nearly ahead and by night she could see the masthead lights of such other vessel in a line or nearly in a line and/or both sidelights." ASSESSMENT OF THIS SCENARIO: The other vessel bears 005° True. Your course is 003° True. The difference is only 2°. Both masthead lights are visible (in a line or nearly so). This is HEAD-ON or nearly head-on. RULE 14(c): "When a vessel is in any doubt as to whether such a situation exists, she shall assume that it does exist and act accordingly." RULE 14 ACTION: (1) BOTH vessels alter to STARBOARD. Rule 14 is symmetric — BOTH are required to alter starboard. Do not assume the other vessel will move first; (2) ACTION SHOULD BE BOLD (Rule 8(b)): alter 15-30° to starboard at minimum — enough to be clearly observable; (3) SOUND SIGNAL: Rule 34(a)(i) — one short blast: "I am altering my course to starboard." Sound BEFORE or simultaneously with the helm action; (4) MONITOR: after altering, confirm on ARPA that the other vessel is also responding and that the new CPA is safe.

B. A 2° difference in bearing means you are in a crossing situation, not head-on. Apply crossing rules — the vessel on your starboard bow is the stand-on vessel.

C. At night, both masthead lights visible means the vessel is meeting you on a collision course. Immediately alter 180° to reverse course and retreat.

D. Maintain course and speed and see if the other vessel alters. Rule 14 applies to the vessel on the port side — you are on the starboard side so the other vessel must give way.

A. 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.

B. A NUC vessel is the stand-on vessel in all situations. Your vessel must maintain course and speed and allow the NUC vessel to take avoiding action.

C. Two black balls means the vessel is at anchor. You should maintain your course but pass with caution at a safe distance as anchored vessels are not give-way.

D. The NUC vessel's situation is a temporary inconvenience. The rules of the road between power-driven vessels apply normally — the vessel on the port side gives way.

A. 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.

B. Ball-diamond-ball is the day signal for a vessel engaged in fishing. At night, a fishing vessel shows red over white all-round lights.

C. RAM vessels have the right of way over all other vessels including sailing vessels. As a power-driven vessel, you must always give way to RAM.

D. Three vertical lights (red-white-red) are shown by a hovercraft operating in the non-displacement mode. This vessel should be treated as a power-driven vessel.