After passing through a fog patch during your watch, describe the documentation you should complete and why.

A. POST-FOG DOCUMENTATION — Chief Mate responsibilities: (1) DECK LOG / OFFICIAL LOG BOOK: entries required — (a) Time visibility reduced below 2nm (or below the threshold requiring fog signals under Rule 35); (b) Speed reduced — note the speed and time; (c) Fog signals commenced — time and mode (making way/stopped); (d) Master called to bridge — time; (e) Additional lookout posted — time; (f) ARPA/radar mode and scale; (g) Any avoiding action taken — time, bearing/range of target, action taken, resulting CPA; (h) Visibility improved — time, speed resumed; (2) PASSAGE PLAN ANNOTATION: note any deviation from planned track taken to avoid traffic in fog — update plan for future transits; (3) VDR: the VDR will have captured the event — no separate action required, but ensure VDR was functioning; (4) COMPANY REPORTING: if near-miss or close-quarters situation occurred — Near Miss Report via SMS; (5) BRIDGE NOTEBOOK: contemporary notes made during the fog event by OOW — times, bearings, CPAs — become legal record in any subsequent inquiry. They must be accurate and contemporaneous; (6) INCIDENT REPORT (if applicable): if fog signals were exchanged with another vessel or an avoiding manoeuvre was made, this may need to be reported to the DPA depending on company SMS threshold; (7) MSIS REPORTING: the Marine Accident Investigation Branch (MAIB) must be notified of any serious marine incident — a near-miss in a TSS would qualify under MAIB reporting criteria.

B. Fog navigation events only require documentation if a collision or near-miss occurred. Routine fog passages do not require any log entries beyond the standard watch log.

C. The VDR records all bridge activity during fog, so manual deck log entries are not required for fog navigation events — the VDR data is the legal record.

D. Documentation of fog events is only required by company SMS if the fog persisted for more than one hour or if visibility dropped below 200 metres.

A. SAFE SPEED IN RESTRICTED VISIBILITY — Rule 6 assessment (COLREG Rule 6): safe speed requires consideration of: (a) state of visibility (300m — severely restricted); (b) traffic density (Dover Strait is one of the world's busiest waterways — separation scheme traffic plus local traffic); (c) manoeuvring ability — your vessel's stopping distance at 12 knots (a 140m bulk carrier may take 15+ ship lengths to stop); (d) background lighting at night; (e) draught — your squat in shallow Dover Strait approaches. AT 12 KNOTS WITH 300M VISIBILITY: stopping distance will greatly exceed 300m — you cannot stop within the distance you can see. Rule 8(e) requires reduction to minimum steerage way if necessary to avoid collision. IMMEDIATE ACTIONS: (1) Sound fog signal — one prolonged blast every 2 minutes (Rule 35a — power-driven vessel underway making way); (2) Reduce speed to safe speed — likely 5-6 knots or less to ensure vessel CAN STOP within visibility range; (3) Post extra lookout — Rule 5 — additional lookouts on bow in fog; (4) ARPA on — operating on appropriate scale, all targets tracked; (5) VHF Ch 16 / Ch 11 (Dover VTS DOVER COASTGUARD) monitored; (6) Navigation lights on; (7) Master already called — correct. Safe speed is your judgement call — document your reasoning in the log.

B. Safe speed in fog is defined as half the vessel's normal service speed. At 12 knots service speed, 6 knots is automatically the correct safe speed under COLREG Rule 6.

C. Rule 6 safe speed assessment applies only when vessels have radar — a vessel without radar is exempt from safe speed requirements in restricted visibility.

D. With visibility of 300m, the vessel should anchor immediately in the Dover Strait to await improvement, regardless of traffic density or depth.

A. RULE 19(d) — Action when radar contact detected (no visual contact): COLREG Rule 19(d): a vessel which detects by radar only another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, take avoiding action in ample time. The action must be: (a) A LARGE ALTERATION OF COURSE — Rule 19(d)(i): if possible, avoid an alteration of course to port for a vessel forward of the beam other than for a vessel being overtaken; (b) AVOID ALTERING COURSE TOWARDS A VESSEL ABEAM OR ABAFT THE BEAM — Rule 19(d)(ii); (c) REDUCE SPEED — reducing speed, stopping engines, or reversing may be needed. IN YOUR SCENARIO: CPA 0.1nm is a close-quarters situation. TCPA 8 minutes gives time for action. RECOMMENDED ACTION: (1) Reduce speed immediately (further — to minimum steerage); (2) Alter course to starboard — large alteration (minimum 30-40°) to open the CPA; (3) Sound appropriate fog signals; (4) Monitor ARPA to confirm action is working — CPA must open; (5) DO NOT alter to port (risk of swinging your bow into the other vessel's path); (6) VHF — if other vessel is a known contact, alert them, but do not rely on VHF agreement. Rule 19 is clear — radar action must be early, substantial, and effective.

B. With CPA 0.1nm and TCPA 8 minutes, the situation is not yet a close-quarters situation under COLREG Rules. Maintain course and speed while monitoring the target.

C. Call the other vessel on VHF Ch 16 and agree a port-to-port passing. Once verbal agreement is reached, no course alteration is necessary.

D. Stop engines and anchor immediately — Rule 19 requires vessels to anchor when a close-quarters situation develops in restricted visibility.