Question 1

You alter course 35° to starboard to avoid a crossing vessel. You took the action 10 minutes before estimated CPA. How do you confirm your action has been effective and what do you do if it has not?

Accepted Answer

Confirming effectiveness of avoiding action: (1) Monitor the bearing of the target continuously after the alteration — a steady bearing still indicates risk of collision; you need the bearing to change (draw aft for a target that was crossing ahead, or draw forward if passing ahead); (2) On ARPA: after 2-3 minutes of track establishment post-manoeuvre, the new CPA should show a safe value (typically >1nm in open water, >0.5nm in coastal areas per company standing orders); (3) On relative motion plot: the new relative motion line should pass astern of your vessel's position by a safe margin; (4) Visual confirmation: if close enough, confirm which sidelight is now visible — the green (starboard) of the other vessel passing ahead, or its sternlight as it passes ahead confirms the situation is resolving. If CPA is NOT improving: the action was insufficient — take further action immediately (additional course to starboard, or reduce speed, or both). Do NOT wait to see if it "sorts itself out." Monitoring post-manoeuvre is the final and critical step in the collision avoidance process, and it is specifically tested at OOW level because many candidates know how to take action but do not systematically verify its effect. ARPA timing: after altering course, the ARPA requires time to recompute the new CPA — the computation depends on the target's track, which takes several minutes to re-establish. An ARPA CPA figure immediately after a course alteration is unreliable — it reflects the old track data. The bearing monitoring method: looking at the compass bearing of the target after the manoeuvre is the fastest and most reliable confirmation — a bearing drawing aft (increasing) for a vessel that was crossing ahead confirms the situation is resolving. The "steady bearing decreasing range" indicator of danger (Rule 7(d)) reverses to "bearing changing + range decreasing but at a decreasing rate" when the action is working. The failure to monitor after taking action has been identified in multiple collision investigations as a critical error — the OOW assumed the action was effective without confirming it, and by the time the developing close-quarters situation was apparent, time for further action had run out.

Question 2

You are OOW on a power-driven vessel underway. You have five vessels near you: a sailing vessel, an NUC vessel, a vessel engaged in fishing, a RAM vessel, and a CBD vessel. Your examiner asks you to rank your responsibilities to each in order.

Accepted Answer

Rule 18 establishes the hierarchy for power-driven vessels underway. In order of priority (highest first — you must give way to all of these in this order): 1st — NUC (not under command): cannot manoeuvre, ultimate priority — Rule 18(a)(i); 2nd — RAM (restricted in ability to manoeuvre): limited manoeuvring ability — Rule 18(a)(ii); 3rd — CBD (constrained by draught): cannot deviate from channel — Rule 18(a)(iii) [note: CBD is optional display — not all CBD vessels show the signal]; 4th — FISHING (engaged in fishing with gear): Rule 18(a)(iv) — note this means fishing with nets/lines, NOT a vessel that has fishing equipment on board but is not actually fishing; 5th — SAILING VESSEL: Rule 18(a)(v) — power gives way to sail (with exceptions in Rule 18(b) where a sailing vessel overtaking a power-driven vessel must keep clear). You must keep out of the way of all five in this order. Rule 18 — Responsibilities Between Vessels — is one of the most fundamental OOW exam topics. The hierarchy from Rule 18(a): (i) NUC; (ii) RAM; (iii) CBD; (iv) fishing; (v) sailing; all are given way over by power-driven vessels. The rules are additive — if you must give way to a CBD vessel, you also must give way to all ranks above it. Key nuances tested at OOW level: (1) CBD is only recognised as a privileged vessel if it displays the signal — a vessel that is constrained by draught but shows nothing is treated as a power-driven vessel; (2) A vessel fishing = one that has gear restricting its ability to manoeuvre; a vessel with rods trolling or no gear deployed = treated as a power-driven vessel; (3) Sailing vessel with engine running (motorsailing) = treated as a power-driven vessel (shows day shape — cone point down); (4) Rule 18(b): nothing in Rule 18 exempts a sailing vessel from keeping clear when overtaking another vessel. The exam will present scenarios where the candidate must apply the correct rule from this hierarchy.

Question 3

You are the stand-on vessel in a crossing situation. The give-way vessel is not taking action. At what point and how do you act under COLREGs Rules 16 and 17?

Accepted Answer

Rule 17 stand-on obligations: (a)(i) — maintain course and speed initially; (a)(ii) — when it becomes apparent the give-way vessel is NOT taking appropriate action, the stand-on vessel MAY take action to avoid collision by her manoeuvre alone; (b) — when a collision cannot be avoided by the give-way vessel alone, the stand-on vessel SHALL take action. The timing sequence: (1) Initially: maintain course and speed — Rule 17(a)(i); (2) Give-way not acting, situation developing: you MAY act to help (Rule 17(a)(ii)) — but only by altering to starboard (not to port for a vessel on your port side, as this creates confusion); (3) Imminent collision, no action possible by give-way alone: you MUST act — Rule 17(b). Sound signal Rule 34(d): if in doubt about another vessel's intentions, give at least 5 short blasts on the whistle immediately. Rule 17 is nuanced and consistently examined. The three stages: mandatory hold (17(a)(i)), permissive action (17(a)(ii)), mandatory action (17(b)). The timing of transition from stage 1 to 2 to 3 is a matter of seamanlike judgement — the examiner will probe this. Key point: Rule 17(c) — when the stand-on vessel takes action under Rule 17(a)(ii) to avoid collision, she shall, if the circumstances of the case admit, NOT alter course to PORT for a vessel on her own PORT side. The reason: if both vessels try to pass to starboard of each other (own vessel altering starboard, give-way vessel finally altering starboard) they could collide — the COLREGs design assumes the stand-on vessel will also go starboard if it must act. Altering to port by the stand-on vessel for a vessel crossing from port risks a collision if both alter in the same direction. Rule 34(d) five short blasts: this is the signal for doubt about the other vessel's intentions or actions to avoid collision — it is NOT the action itself; it alerts the other vessel that action may be necessary.