Question 1

At night you pass an unlit buoy at a position where your chart shows a Fl.G 5s starboard lateral mark. The buoy appears dark. What actions do you take?

Accepted Answer

Unlit buoy where a light is charted: (1) Treat the position with caution — the buoy may have a faulty light or may be off-station; the safe water it marks is still hazardous regardless of the light status; (2) Navigate around the buoy's charted position maintaining the appropriate clearance as if the light were working — do not rely on the light being absent to indicate the hazard has moved; (3) Report the unlit buoy to the relevant lighthouse authority: in UK waters — Trinity House (England/Wales/Channel Islands), Northern Lighthouse Board (Scotland/Isle of Man), Commissioners of Irish Lights (Ireland). Report via VHF Ch 16 to MRCC or by telephone or via the online ATON defect reporting systems; (4) Note in the deck log: time, position, nature of the defect, action taken; (5) Make a NAVTEX/MSI broadcast if appropriate and if your vessel has the facility — or request MRCC to issue a broadcast warning to other vessels. Aid to Navigation (AtoN) defect reporting is a legal obligation for UK mariners and a professional duty internationally. In the UK, the Maritime and Coastguard Agency and the General Lighthouse Authorities (Trinity House, NLB, CIL) coordinate AtoN maintenance. The reporting obligation: Merchant Shipping Notice MSN 1819 and related MCA guidance require masters to report any AtoN defects. The practical navigation principle: an unlit buoy still marks a physical hazard — the hazard has not moved because the light failed. "The light is out but the danger is still in" is the practical rule. The buoy itself can still be detected by radar if it has a radar reflector or racon — check the chart for any radar capability listed for the mark. Navigation without the expected light: use chart to determine the safe passing distance and navigate on that basis using radar or GPS to confirm position relative to the charted position of the buoy. The log entry and report are standard professional obligations that any near-coastal OOW must demonstrate knowledge of.

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.