Passage planning

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Poor passage planning and deviation from the plan can lead to groundings and oil spills.

Passage planning or voyage planning is a procedure to develop a complete description of vessel's voyage from start to finish. The plan includes leaving the dock and harbor area, the enroute portion of a voyage, approaching the destination, and mooring. According to international law, a vessel's captain is legally responsible for passage planning,^[1] however on larger vessels, the task will be delegated to the ship's navigator.^[2]

Studies show that human error is a factor in 80 percent of naviational accidents and that in many cases the human making the error had access to information that could have prevented the accident.^[2] The practice of voyage planning has evolved from penciling lines on nautical charts to a process of risk management.^[2]

1 Stages of passage planning
2 Computer aids
3 See also
4 Notes and references

[edit] Stages of passage planning

Passage planning consists of four stages: appraisal, planning, execution, and monitoring,^[2] which are specified in International Maritime Organization Resolution A.893(21), Guidelines For Voyage Planning,^[3] and these guidelines are reflected in the local laws of IMO signatory countries (for example, Title 33 of the U.S. Code of Federal Regulations), and a number of professional books and publications. There are some fifty elements of a comprehensive passage plan depending on the size and type of vessel, each applicable according to the individual situation.

The Guidelines specify three key items to consider in the practice of voyage planning:

having and using a voyage plan is "of essential importance for safety of life at sea, safety and efficiency of navigation and protection of the marine environment."^[3],
voyage planning is necessary for all types of vessels on all types of voyages.^[3]
the plan's scope should be based on all information available, should be "berth to berth," including when under pilotage, and the plan includes the execution and the monitoring of progress.^[3]

Reviewing nautical publications is part of the appraisal stage.

[edit] Appraisal

Before each voyage begins, the navigator should develop a detailed mental model of how the entire voyage will proceed. The appraisal stage consists of gathering and contemplating all information relevent to the voyage. Much of this appraisal is done by consulting nautical charts, nautical publications and performing a number of technical tasks such as weather forecasting, prediction of tides and currents, and checks of local regulations and warnings.^[3]

Nautical publications are a valuable guide to local conditions and regulations, but they must be updated and actually read to be of any use.^[4]These publications could include Sailing Directions and Coast Pilots or similar texts produced by other authorities.^[3]

[edit] Planning

Once information is gathered and considered, the navigator can begin the process of actually laying out the voyage. The process involves projecting various future events including landfalls, narrow passages, and course changes expected during the voyage. This mental model becomes the standard by which the navigator measures progress toward the goal of a safe and efficient voyage, and it is manifested in a passage plan.

A good passage plan will include a track line laid out upon the best-scale charts available. This track is judged with respect to at least nine separate criteria given in the Guidelines including underkeel clearance, safe speed, the use of routing and reporting services, and the availability of contingencies in case of emergency.^[3]

The navigator will draw and redraw the track line until it is safe, efficient, and in line with all applicable laws and regulations. When the track is finished, it is becoming common practice to also enter it into electronic navigation tools such as a Electronic Chart Display and Information System, a chartplotter, an ARPA system, or a GPS unit.

When working in a team environment, the passage plan should be communicated to the navigation team in a pre-voyage conference in order to ensure that all members of the team share the same mental model of the entire trip.

Monitoring progress and comparing it to the plan are key to passage planning.

[edit] Execution

The IMO was careful to include execution as part of the process of passage planning. This underscores the fact that the Guidelines list a number of tasks that are to executed during the course of the voyage. It also reiterates the captain's responsibility to treat the plan as a "living document" and to review or change it in case of any special circumstances that should arise.

[edit] Monitoring

Once the voyage has begun the progress of the vessel along its planned route must be monitored. This requires that the ship's position be determined, using standard methods including dead reckoning, celestial navigation, pilotage, and electronic navigation.

According to the Guidelines, the passage plan should always be available to the officer on watch on the bridge. The Guidelines also specify that deviations from the plan should be clearly recorded and be consistent with other provisions of the Guidelines.^[3]

[edit] Computer aids

Modern navigators often enter passage plans on electronic systems

Passage planning software can greatly simplify the process and ensure that nothing important is overlooked. A good passage planning software program will include great circle waypoint/distance calculators, tide and tidal current predictors, celestial navigational calculators, consumables estimators for fuel, oil, water, and stores, and other useful applications.