Your vessel is requested to take a disabled cargo vessel in tow. As Chief Mate, your examiner asks: "What are your considerations and actions before commencing a tow?" Give a management-level answer.

A. Pre-tow considerations: assess own vessel's capability (engine power, towing bitts/cleats rating, bollard pull); contact master and company/DPA; legal: salvage or towage — issue Lloyd's Open Form (LOF) or agree terms. Prepare tow: suitable towing hawser (length, breaking strength, material — nylon for elasticity preferred); connection method on towed vessel (messenger line, heaving line, attach to tow point); safety distance during approach in current sea state; emergency release arrangement. Inform MRCC and port state; update voyage plan; crew fatigue plan for extended tow. Monitor: tow wire catenary; compass heading of towed vessel; any risk of tow wire fouling propeller. Communications plan with towed vessel throughout.

B. Approach the disabled vessel from downwind and connect a line from the stern. No special equipment is required — any mooring line is suitable for short-distance towing.

C. Towing is a commercial operation managed by the company. The Chief Mate should await instructions from the DPA before taking any action.

D. Standard anchor chain is the preferred towing medium because it is strong and resistant to chafe. The tow should be conducted at maximum safe speed to reduce exposure time.

A. At management level: hull fouling and speed/fuel trade-off; weather routing service integration; piracy risk assessment (Gulf of Guinea — IMB/BMP6 procedures, MSCHOA registration, citadel arrangements); regional seasonal weather (harmattan, North Atlantic gales timing); full port approach analysis for Lagos (pilot boarding area, VTS, port congestion, anchorage assessment, agent contacts); cargo condition requirements throughout (ventilation against condensation in tropical transit); crew fatigue management across the voyage duration; load line zone changes (Summer to Tropical); emergency contingency analysis (abort ports, refuge areas); environmental compliance across all jurisdictions transited.

B. The Chief Mate passage plan is identical to the OOW plan. The difference is only that the Chief Mate signs it and presents it to the master for approval.

C. At management level, the primary additional consideration is fuel consumption optimisation. Safety planning is the OOW's responsibility during the voyage itself.

D. Management-level passage planning focuses on commercial considerations such as ETA commitments and port scheduling. The safety elements are unchanged from OOW level.

A. Parallel indexing uses a radar index line set parallel to the vessel's intended track at a known distance from a fixed radar target (headland, breakwater, isolated rock). As the vessel proceeds, the radar echo should remain on or near the index line — deviation indicates the vessel is off-track. Used for: restricted visibility coastal passages; harbour approaches; narrow channel navigation where fixed marks are reliably radar-conspicuous. Limitations: requires a strong, reliable radar target that returns a consistent echo; dependent on radar accuracy (beam width, set and drift errors); can give false confidence if the target gives ambiguous echoes; does not replace visual fixing when available.

B. Parallel indexing is a technique for comparing two radar targets simultaneously. It is only used when ECDIS is not available.

C. Parallel indexing measures the distance between two vessels on radar. The index line represents the minimum CPA required and alarms when breached.

D. Parallel indexing is an ARPA function that automatically plots the vessel's track and corrects for set and drift. It requires no manual input from the navigator.