Question 1

At night you observe a vessel ahead showing: two masthead lights (forward, the after one higher), red and green sidelights, a yellow all-round light above the sternlight, and a third masthead light higher still making three in a vertical line. There is another vessel 300m astern of her. What is this combination?

Accepted Answer

Three masthead lights in a vertical line (forward mast) PLUS yellow towing light above the sternlight: this is a TOWING VESSEL where the length of tow exceeds 200 metres — Rule 24(a)(ii). Rule 24(a): a vessel towing shows: (i) forward masthead light(s) — two if tow ≤200m, three if tow >200m; (ii) sidelights; (iii) sternlight; (iv) a yellow towing light in a vertical line with and above the sternlight. The towed vessel 300m astern would show: sidelights and sternlight only (Rule 24(e) — a vessel being towed shall exhibit sidelights and a sternlight). The distinctive combination for a long tow is the third masthead light — if you see three vertical masthead lights on the towing vessel, the tow is over 200m. Give a very wide berth — the tow wire/hawser between the vessels is invisible and submerged. Rule 24 towing lights are consistently examined because towing arrangements create significant collision risk — the tow wire between the towing vessel and the tow is a serious hazard. Key Rule 24 points: (a)(i): when tow ≤200m, towing vessel shows TWO masthead lights; (a)(ii): when tow >200m, THREE masthead lights. The yellow towing light: positioned vertically above the sternlight — this distinguishes a towing vessel from any other vessel which shows only a white sternlight. The towed vessel: typically shows only sidelights and a sternlight (Rule 24(e)). If the towed vessel is partly submerged or difficult to see, additional lights are shown. By day: towing vessel shows a diamond shape where best seen when the tow exceeds 200m. The examiner at OOW level will test whether the candidate knows the 200m threshold and the yellow towing light position. The practical seamanship point: pass well astern of the towing vessel, not between the towing vessel and the tow — the hawser is often 50-200m below the surface and invisible.

Question 2

At night you observe a vessel showing: two all-round red lights in a vertical line. No other lights visible. You are approaching on her starboard bow at 2nm. What is this vessel, what are your obligations, and what do you monitor?

Accepted Answer

Two all-round red lights in a vertical line: this is a VESSEL NOT UNDER COMMAND (NUC) — Rule 27(a). The vessel is unable to manoeuvre as required by COLREGs due to some exceptional circumstance. Obligations: Rule 18 — all power-driven vessels must keep out of the way of a NUC vessel. You are the give-way vessel regardless of aspect or crossing/overtaking geometry. Actions: alter course and/or reduce speed early and substantially to keep clear; do NOT cross ahead of a NUC vessel. Monitor: watch for any green (starboard) or white (sternlight) becoming visible — this confirms aspect and direction of drift; watch for any additional lights (towing, dredging); check for any DSC/MAYDAY on DSC Ch70 or Ch16 — a NUC vessel may be in distress. Rule 35 fog signals for NUC: two prolonged + one short blast every 2 minutes if making way; two prolonged if stopped. Rule 27(a) is unambiguous: two all-round red lights in a vertical line = NUC. This is one of the most commonly tested vessel identification lights at OOW level. The examiner will vary the context — approaching from different angles, in a channel, in restricted visibility — to test whether the candidate applies the correct Rule 18 obligation regardless of geometry. Confusion points: two all-round RED (not white) vertical lights = NUC; two all-round WHITE vertical lights in addition to masthead/sidelights = power-driven vessel over 50m underway (forward and after masthead lights). NUC by day: two black balls in a vertical line. Monitoring considerations: a NUC vessel may be drifting with the current and wind — its actual track through the water (and over ground) may be very different from any apparent heading. Use radar to determine the rate of drift and set, not just the bearing. Sound signals from a NUC vessel should trigger immediate concern if heard in restricted visibility.

Question 3

You observe a vessel at night showing: one all-round red light and one all-round white light below it, in a vertical line. She also shows sidelights and a sternlight. Bearing 210° at 4nm. What is this vessel?

Accepted Answer

All-round red over white in a vertical line WITH sidelights: this is a PILOT VESSEL underway — Rule 29(a)(i). The red over white is the internationally recognised pilot vessel identification light. The sidelights confirm she is underway and making way. Obligations: no specific Rule 18 obligation to keep clear of pilot vessels — they are treated as power-driven vessels underway for collision avoidance purposes (Rule 18 list does not include pilot vessels). Apply normal Rules 12-17 based on aspect and situation. By day: pilot vessels display the international flag "H" (Hotel — vertical halves, white and red). Rule 29 — Pilot vessels: "A vessel engaged on pilotage duty shall exhibit at or near the masthead, the lights prescribed in paragraph (a) of this Rule, consisting of two all-round lights in a vertical line, the upper being white and the lower red." Wait — check: Rule 29(a)(i) states upper RED and lower WHITE? No: Rule 29(a)(i): "at or near the masthead, two all-round lights in a vertical line, the upper being white and the lower red." Correction: UPPER WHITE, LOWER RED. The examiner card shows red over white — this would be an error or a test of careful reading. In the COLREGs text, pilot vessels show WHITE over RED (upper white, lower red). Red over white does not correspond to a Rule 29 pilot vessel — candidates must know the correct order. The correct pilot vessel light is WHITE (upper) over RED (lower). This question as presented would catch candidates who have memorised "pilot = red over white" incorrectly. At exam level, precise knowledge of the vertical order of lights is tested.