You observe a vessel ahead showing green over white all-round lights at night. What type of vessel is this, and does she have priority over your power-driven vessel?

A. Fishing vessels only have priority over power-driven vessels in areas specifically designated as fishing grounds. In open waters, normal crossing and overtaking rules apply.

B. Green over white lights indicate a pilot vessel on station. This vessel has priority over all other vessels in the vicinity.

C. FISHING VESSEL — CM IDENTIFICATION: A vessel showing ALL-ROUND GREEN OVER WHITE lights is a VESSEL ENGAGED IN FISHING (not trawling). Rule 26(c)(i): "A vessel engaged in fishing, other than a vessel trawling, shall exhibit: two all-round lights in a vertical line, the upper being green and the lower white." TRAWLER: Rule 26(b): "A vessel engaged in trawling... shall exhibit two all-round lights in a vertical line, the upper being green and the lower white, and if making way through the water, in addition sidelights and sternlight." BOTH types show GREEN over WHITE — the additional lights indicate the difference. TRAWLER: making way = sidelights + sternlight (same lights as fishing but also underway lights). FISHING VESSEL NOT TRAWLING (set nets, lines, etc.): if gear extends more than 150m in any direction — shows an additional all-round white light in the direction of the gear. Day signal: a CONE (apex down) indicates a fishing vessel with any type of gear. ALL-ROUND YELLOW FLASHING LIGHT: purse-seiner vessel engaged in fishing. YOUR OBLIGATION: Rule 18(a): "A power-driven vessel underway shall keep out of the way of a vessel engaged in fishing." YES — a fishing vessel HAS priority over your power-driven vessel. Action: keep clear, pass astern of the fishing vessel, be especially wary of nets and gear that may extend from her. Watch for additional white light indicating gear direction; (b) A fishing vessel is NOT exempt from the rules — she must still keep clear of NUC and RAM.

D. All-round green over white lights are not a recognised COLREG signal. The vessel may be displaying incorrect lights and should be contacted on VHF.

A. 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.

B. 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.

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 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.

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 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.

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.