Question 1

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 2

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.

Question 3

You are OOW on a 350 GT coastal ferry. A 15m sailing yacht is proceeding through a narrow channel at 4 knots under sail — too slow for your schedule. You want to overtake. What rules apply and how do you proceed?

Accepted Answer

Two competing rules apply: Rule 13 (Overtaking) — you are coming up from behind = overtaking vessel = GIVE WAY vessel must keep clear of the yacht. AND Rule 9(b) — a sailing vessel shall not impede the passage of a vessel (your 350 GT ferry) which can safely navigate only within the narrow channel. The interaction: Rule 9(b) creates an obligation on the sailing vessel not to impede you — but this does not automatically give you the right to overtake. Rule 9(e)(i) further restricts overtaking in narrow channels: "a vessel shall not overtake, or shall take all necessary precautions when overtaking, another vessel proceeding in the same direction within a narrow channel or fairway." Safe overtaking procedure: (a) Sound 2 prolonged + 1 short blast (Rule 34(c)(i) — intention to overtake on the other vessel's starboard side); (b) Await the sailing vessel's agreement signal (1 prolonged + 1 short — Rule 34(c)(ii)); (c) If insufficient room, wait or signal the sailing vessel on VHF. This scenario requires the candidate to navigate the interaction between Rules 9, 13, and 18 simultaneously — a characteristic Chief Mate and above level question presented here as a near-coastal scenario because it involves a small vessel. Rule 9(b) obligation on the sailing vessel: the yacht "shall not impede" your passage — this means the yacht should move to the edge of the channel to allow passage if possible. However, the yacht is under sail and its ability to do so quickly depends on wind conditions. Rule 13 obligation on you: you are overtaking = give-way. These don't cancel — they stack. You must keep clear AND the yacht must not impede you. The prescribed sound signal for overtaking in a narrow channel (Rule 34(c)): 2 prolonged + 1 short = "I intend to overtake you on your starboard side." The sailed vessel then either confirms (1 prolonged + 1 short = agreement) or sounds 5 short blasts = I disagree / the manoeuvre is unsafe. At near-coastal level, this is tested because ferry operations on coastal routes routinely encounter this exact situation.

Colregs Buoyage Small Vessel Practice Questions