Piloting (navigation)
Introduction
Piloting, also known as pilotage, is a method of navigation that involves the use of visual references and depth soundings to determine a vessel's position and guide its course. This technique is primarily used in coastal or inland waters where landmarks and navigational aids are visible.
History
The art of piloting has been practiced since ancient times. The Phoenicians, known for their seafaring skills, were among the first to use visual landmarks and the depth of the sea to navigate their vessels. They would use primitive tools like lead lines for depth sounding and landmarks such as mountains or unique rock formations to determine their position.
Principles of Piloting
Piloting involves several key principles, including position fixing, dead reckoning, and course plotting.
Position Fixing
Position fixing is the process of determining a vessel's exact location using visual references and depth soundings. This is typically done by identifying two or more known points on land and measuring the angles between them from the vessel. The intersection of these lines of position on a chart gives the vessel's location.
Dead Reckoning
Dead reckoning is a method of estimating a vessel's current position based on a previously known position, the course the vessel has been steering, the distance it has traveled, and the time that has passed. This technique is often used when visual references are not available.
Course Plotting
Course plotting involves determining the direction in which a vessel should be steered to reach its destination. This is done by drawing a line on a chart from the vessel's current position to its destination and measuring the angle of this line relative to a north-south line.
Tools and Techniques
Various tools and techniques are used in piloting, including charts, compasses, depth sounders, and electronic navigation systems.
Charts
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. It provides information on depths of water, nature of the seabed, topography of the coast, and locations of navigational aids.
Compasses
A marine compass is used to determine the vessel's heading. It is a vital tool in piloting as it allows the navigator to maintain a steady course and accurately measure angles between landmarks.
Depth Sounders
A depth sounder, also known as an echo sounder, is a device used to measure the depth of water beneath a vessel. It works by emitting a sound pulse and measuring the time it takes for the echo to return from the seabed.
Modern vessels often use electronic navigation systems such as GPS and radar to aid in piloting. These systems provide real-time information on the vessel's position and can detect other vessels or obstacles in the water.
Limitations and Challenges
While piloting is a fundamental skill for any mariner, it has its limitations and challenges. These include limited visibility conditions, inaccuracies in charts, and the need for constant vigilance.
Training and Certification
In many countries, mariners are required to undergo training and obtain certification in piloting. This typically involves coursework in navigation theory, practical training, and examinations.