Question 1

You are approaching a narrow coastal channel at night. A vessel ahead is stopped and showing two all-round red lights in a vertical line. No other lights are visible. What must you do?

Accepted Answer

Two all-round red lights vertical = NOT UNDER COMMAND (NUC) — Rule 27(a). This vessel cannot manoeuvre. If it is stopped in the channel ahead, it may be blocking the navigable passage. Actions: (1) Reduce speed immediately; (2) Rule 18 — you must keep out of the way of an NUC vessel; (3) Do NOT proceed past the NUC vessel without confirming there is sufficient room; (4) Contact the vessel on VHF Ch 16 — ascertain the nature of the problem and whether the channel is passable; (5) Contact the port/harbour authority — they need to know about a vessel blocking the channel; (6) If the channel is too narrow to pass, stop or anchor and await either the NUC vessel regaining power or harbour authority guidance; (7) Listen for any DSC or MAYDAY on Ch 16/Ch 70 — the vessel may be in distress; (8) Sound a fog signal (if restricted visibility applies) or use Rule 34(d) five short blasts to signal danger if approaching too close. NUC identification and response applies regardless of vessel size — Rule 27(a) does not specify a minimum size for NUC status. A 10m motor cruiser with engine failure is equally NUC as a 200m cargo vessel with engine failure. The two red lights vertical is the same signal regardless of vessel size. The small vessel context adds a practical complication: a small NUC vessel is harder to see, may be drifting faster relative to channel width, and the crew may be less experienced in signalling their status or communicating on VHF. In a narrow coastal channel, an NUC vessel is an acute hazard because it cannot move clear. The harbour authority contact is important: tidal channels are often managed by harbour masters who have the authority and means to assist disabled vessels (towboat, pilot launch). At near-coastal level, the OOW may be the only officer on the bridge with limited crew — the management of this situation tests both COLREGs knowledge and situational awareness.

Question 2

You are OOW on a 180 GT coastal supply vessel. At night you observe a small sailing vessel showing only a combined red and green lantern at the bow — no white lights visible anywhere. What is this vessel legally showing and are you required to give way?

Accepted Answer

Combined bow lantern (bicolour lantern) — red (port) and green (starboard) sectors combined in one fitting at the bow — is permitted for sailing vessels under 20m in length under Rule 25(b) and (c): Rule 25(b) permits a combined lantern (red/green/white all in one unit at the masthead); Rule 25(c) permits an all-round white light plus the sidelights. For very small vessels under 7m: Rule 25(d) — if not reasonably practicable to show the prescribed lights, show an electric torch or lighted lantern showing a white light in sufficient time to prevent collision. The vessel showing only the bicolour bow lantern without any white sternlight is technically non-compliant unless it is under 7m using the Rule 25(d) exemption. However: it IS a sailing vessel regardless — you must give way under Rule 18(a)(v). Monitor carefully — the lack of sternlight makes aspect determination difficult. Use radar to determine course and speed. Small sailing vessel lighting arrangements are tested at near-coastal level because coastal waters in the UK contain large numbers of recreational sailing vessels, yachts, and small craft. Rule 25 permits multiple lighting options for sailing vessels, and the variety means the OOW must be able to identify sailing vessel status from whatever lights are shown. Key Rule 25 variants: (a) standard (any size): separate sidelights + sternlight; (b) under 20m: optional combined tricolour at masthead instead; (c) additional option: all-round red over green lights at the top of the mast to be more visible; (d) under 7m or rowing boats: white torch/lantern when in danger of collision. The COLREGs obligation to give way to sailing vessels (Rule 18(a)(v)) applies regardless of whether the sailing vessel is showing its lights perfectly. Non-compliance with light rules by the sailing vessel does not remove the power vessel's give-way obligation — Rule 2(a) requires taking all precautions required by ordinary seamanship.

Question 3

Approaching a harbour entrance, you see (from seaward): a red can buoy to the north of the channel, a green conical buoy to the south of the channel, then a port-hand mark showing Fl.R every 4 seconds. You are heading west (270°) into the harbour. Describe how you navigate through these marks.

Accepted Answer

IALA System A — entering harbour heading west: "Red to Port Returning." (1) Red can buoy to the NORTH of the channel: it is on the port side of the channel (keep it to port) — it marks the northern edge of safe water; your channel track runs to the south of it; (2) Green conical buoy to the SOUTH: it is on the starboard side — keep it to starboard; your channel track runs to the north of it; (3) Fl.R every 4 seconds port lateral mark ahead: red light, any rhythm = port hand mark — keep this to PORT as you pass through the entrance. Navigation: steer a course keeping the red buoy to your port (north of track), green buoy to your starboard (south of track), and the Fl.R to your port as you enter. The area of safe navigation is between the red (port) and green (starboard) lateral marks. Lateral mark navigation is the most practical buoyage skill for coastal and near-coastal OOWs. The key principle: "conventional direction of buoyage" defines port and starboard — in harbour approaches it is from seaward into the harbour. The OOW heading west into a harbour is heading IN the conventional direction (from sea to harbour) — so IALA A port/starboard conventions apply directly: RED = PORT side of safe water (keep to port), GREEN = STARBOARD side (keep to starboard). The phrase "Red to Port Returning" summarises this for IALA A. The Fl.R light characteristic: in IALA A, port lateral marks use RED lights; starboard lateral marks use GREEN lights. Any rhythm of red flashing = port hand mark; any rhythm of green flashing = starboard hand mark. The light rhythm (4 second period in this case) does not change the colour convention — only cardinal marks have specific group-count requirements. At near-coastal OOW level, the examiner expects instant confident application of IALA A conventions in realistic harbour approach scenarios.