Passage planning in four stages: appraisal, planning, execution and monitoring

Stage 1: appraisal

Appraisal is gathering and weighing the information the plan needs. Without it, the plan will be built on assumptions. Be ready to say what you would collect and why.

• Charts and publications: the largest-scale corrected charts for the route, sailing directions, list of lights, tide tables and tidal stream atlases, and the current notices to mariners and navigational warnings.
• The ship: draught, manoeuvring characteristics, the state of equipment, crew experience and any defects affecting navigation.
• The environment: weather forecasts and climate information, seasonal hazards, currents, ice and the limits of daylight.
• Rules and services: routeing and traffic separation schemes, pilotage and vessel traffic services, reporting requirements, protected or restricted areas and port requirements.
• The cargo and voyage requirements: the ship’s schedule, the cargo’s particular needs and any deadlines that might tempt shortcuts.

Stage 2: planning

Planning turns the appraisal into a detailed berth-to-berth plan. A good plan covers these elements.

• The track: courses and waypoints on the chart, kept clear of hazards with safe margins either side, and with wheel-over positions worked out for each turn using the ship’s turning characteristics.
• Margins of safety: the distance off dangers that is acceptable, the no-go areas and the limits of the safe corridor.
• Under-keel clearance: the depth needed at each part of the route, taking account of tide, squat and other effects.
• Speeds and times of arrival, including tidal windows, pilot boarding times, daylight and port operating hours.
• Position monitoring: primary and backup methods, the interval between fixes, and parallel indexing or other visual and radar checks that suit the route.
• Contingencies: abort points beyond which the ship cannot turn back, alternative routes, safe anchorages and emergency actions.
• Communication: reporting points, VTS contacts and what will be sent to whom.

Under-keel clearance

Under-keel clearance is a question examiners like because it forces you to combine concepts. Start with the ship’s static draught and the charted depth, corrected for the height of tide. Then allow for squat, which increases with speed and in shallow or confined water, for heel caused by a turn or wind, for wave-induced motion, for the accuracy of the charted depth and for the water’s density if relevant. What remains is the margin. Explain it as a policy: the company or port sets the minimum margin and the plan should show that it is achieved along the whole route.

Electronic chart displays

On a ship using an electronic chart display and information system the plan is entered into the system, but the thinking is the same. Be prepared to explain the safety contour, safety depth, shallow contour and deep contour, how the system’s look-ahead and alarm functions are set up for the voyage, how chart updates are applied, and what backup arrangements exist if the system fails. Be able to say why you would not rely on one source of position. An alarm only helps if it has been set appropriately and the watchkeeper understands what it means.

Stage 3: execution

Execution is carrying out the plan, taking account of the circumstances that exist. It begins with a bridge team briefing, so that everyone knows the plan, their roles, the hazards and the points at which the Master must be called. It also includes deciding whether the plan still suits the conditions. Plans are made in advance, and the weather, traffic or the ship’s condition can change.

Explain how you would handle changes: when you would adjust the plan, when you would stop and reappraise, and how you would record and communicate the change.

Stage 4: monitoring

Monitoring is checking, continuously, that the ship is where the plan says she should be and that the plan remains safe. It relies on regular position fixing by independent methods, comparing the ship’s progress against the plan, observing the depth, watching other traffic and weather, and a watchkeeper who is willing to challenge. It also relies on the culture of the bridge: an officer who is uncertain should say so and call the Master.

Be able to describe what you would do if the ship were found to be off track, if two position sources disagreed, or if visibility deteriorated unexpectedly near a hazard.

Pilotage and the Master’s responsibility

Taking a pilot does not remove the bridge team’s responsibilities. The pilot advises, and the Master remains in command. Explain how you would exchange information with a pilot, brief the team on the pilot’s plan, and challenge a pilot’s actions if you had concerns.

Practising a plan

1. Choose a real passage you have made, and describe each of the four stages in order.
2. Pick the most hazardous leg and work out the track, margins, wheel-over, under-keel clearance and contingencies.
3. Explain the bridge team briefing you would give, then ask a colleague to question the plan.
4. Change a condition, such as visibility, a failed gyro or a delayed tide, and explain how the plan changes.

Official sources

This guide was written from the following sources. Requirements change, so confirm the current position with the source before relying on it.

• IMO: SOLAS, International Convention for the Safety of Life at Sea
• IMO: COLREG, Convention on the International Regulations for Preventing Collisions at Sea
• AMSA: Prepare for your oral exam (syllabi, checklists and study sheet)

Related certificate guides

• Master Unlimited
• Chief Mate Unlimited
• AMSA OOW (Watchkeeper Deck)
• Master <100 m Near Coastal
• AMSA oral exam preparation guide

Keep reading

• COLREGs: a method for reasoning through any situation
• Master Unlimited oral exam: the themes behind the questions
• OOW and Watchkeeper Deck oral exam: the themes behind the questions
• Maritime glossary for plain-language definitions of the terms used here.
• More in Navigation, or browse the knowledge centre.