Steady Bearing in a Traffic Lane with Fog Ahead
At 2210 UTC your 18-knot container ship is steering 075° in the north-east-bound lane of a traffic separation scheme. Visibility is 1.5 NM and decreasing; radar shows a 12-knot vessel on a steady bearing 3.8 NM away, 35° on your starboard bow, apparently crossing from starboard to port. The bearing is not changing and the range is closing at about 0.6 NM per minute. A second echo, probably a small fishing vessel, is 1.2 NM on your port bow and showing no consistent aspect. The traffic lane is 6 NM wide; the nearest lane boundary is 1.0 NM to port. A fog bank is visible ahead and the radar range is set to 6 NM. The OOW has already called the master, who is on the bridge. The crossing vessel does not answer VHF calls on channel 16.
1. Determine whether risk of collision exists, which COLREG rules apply, and what action you would take.
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Risk of collision exists: the bearing is steady and the range is closing at 0.6 NM/min from 3.8 NM, so the TCPA is about 6 minutes and the CPA is likely near zero. Rule 7 requires a risk assessment based on compass bearings and radar plotting, not on VHF.
Rule 10: own ship is in a traffic lane and must proceed in the general direction of the lane. The crossing vessel should cross on a heading as nearly as practicable at right angles and should not impede the flow of traffic. But Rule 10(j) does not relieve either vessel of the other rules; because the crossing vessel is on the starboard side, Rule 15 makes own ship the give-way vessel. That apparent conflict is resolved by taking early, substantial action and not relying on the other vessel's duty.
Action: reduce speed at once and sound five short and rapid blasts; switch to hand steering; engage engine standby; and, because the vessel is forward of the beam and visibility is deteriorating, alter course to starboard to pass astern if there is sea room. A starboard turn also increases clearance from the lane boundary 1.0 NM to port and from the fishing vessel on the port bow. Do not alter to port. If the crossing vessel still does not open the bearing, stop or take all way off rather than try to cross ahead.
2. Explain the sound signals and restricted-visibility obligations that now apply.
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On entering restricted visibility, Rule 19 applies. As a power-driven vessel making way, sound one prolonged blast at intervals of not more than 2 minutes; if stopped, two prolonged blasts with a 2-second interval. If a close-quarters situation develops, five short and rapid blasts. Reduce speed to the minimum at which the ship can be kept on course, have the engines ready for immediate manoeuvre, and use radar, compass bearings and lookouts. Rule 19(d) prohibits altering course to port for a vessel forward of the beam, except when overtaking, and prohibits altering toward a vessel abeam or abaft the beam. VHF may be used to clarify intentions but is not a substitute for radar plotting or the rules. The fishing vessel is a separate risk: keep clear and avoid turning into her.
3. What bridge-team checklist would you complete in the next 3 minutes?
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Within three minutes: master has command; hand steering; engine standby and bridge control ready; two lookouts forward and one aft; radar on short range, ARPA re-plot of the crossing vessel and fishing vessel; sound signals started; VHF call to VTS and repeated call to the crossing vessel; positions plotted and lane boundary monitored; course/speed recorded; rescue boat and lifebuoys ready only if needed; and the decision point for a further alteration or a full stop identified. The OOW should announce each action aloud so the bridge team shares the same picture.