Pilotage

For the novel by Nevil Shute, see Pilotage (novel).

Pilotage is the use of fixed visual reference on the ground or sea by means of sight or radar to guide oneself to a destination, sometimes with the help of a map or nautical chart. People use pilotage for activities such as guiding vessels and aircraft, hiking and scuba diving. Pilotage techniques apply when close enough to land or other navigational reference points. In these circumstances there is often not enough time for more elaborate navigational techniques that are used when out of sight of both navigational aids and hazards. In these circumstances, it is usually not necessary to know exactly where you are, but that one is in a safe position, or at least on a safe line and will remain so for a period of time, and to know when the next change will be required.

Without such pilotage references, it is necessary to navigate using dead reckoning (typically with a compass and some form of log for speed or distance estimation), radar, radio navigation, and satellite navigation (such as GPS).

Difficulties

Pilotage depends on the pilot being able to recognise the visual references in order to make use of them. The pilot must either be familiar with those visual references or be able to discover them from a map, aeronautical chart or nautical chart. Many nautical and aeronautical disasters have resulted from the pilot incorrectly identifying visual references.

Poor visibility may affect safe pilotage by obscuring the natural features used by pilots in an area. In such situations, pilots use navigational aids such as radar and the GPS to determine position and monitor their passage.

Visual features

Common types of visual reference point used for pilotage:

During the day:

• Natural features: Mountains, hills, lakes, rivers and coastal features such as cliffs, rocks and beaches
• Man made nautical features: sea marks, landmarks and radio aerials
• Man made land features: Airports, cities, dams and highways

At night:

• Man made nautical features: Lighthouses, lightvessels and sea marks with lights
• Man made land features: Airports, illuminated towers and buildings

While not strictly a "visual feature," depth, measured by electronic means or manually (with a lead line), can also be an important element of pilotage.

Pilotage is frequently combined with navigation techniques such as dead reckoning. When a pilot at a known location cannot see the next visual reference on the route to a destination, he or she can use dead reckoning to get closer to the next reference point. This is the most common form of VFR navigation.

See also

• Maritime pilot
• American Practical Navigator

References

• it:Pilotaggio