Chapter 1 Navigation

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This chapter explains all the principles of navigation on a 'blank chart'. (There is a separate chapter which goes into what is printed on the chart - not necessary at this stage). The following topics are covered:

a) Position. How it is defined: latitude and longitude. How you plot your position on a chart, and devices that give you your position in latitude and longitude.

b) Distance and speed. Defined as nautical miles and knots. The log for measuring distance and speed.

c) Direction. How it is defined in degrees from North. The magnetic compass, magnetic variation and deviation.

d) How to navigate. The tools of the trade for chartwork. Dead Reckoning (DR) and Estimated Position (EP). Course to steer to allow for tide and leeway.

e) How to fix your position. The Global Positioning System (GPS) and other electronic devices.

f) Position lines and the three bearing fix. Various other position lines. Transferred position lines. Clearing lines.

g) Glossary of navigational terms.


Navigation is the process of finding your way from one place to another.

On land this has become pretty easy, because you can follow roads, and signs are provided to guide you. The reason it is not so simple at sea is that you are in an open space with no roads or paths. That is why you need some different techniques to find your way around.

Generally these techniques are fairly simple and common sense, but we don’t use them in every day life, so there are a few new concepts to learn. This chapter explains them.

We start with the fundamentals: how do you define something’s position? How do you measure distance, speed and direction? Using these building blocks we then explain how you can find your way from one place to another, and how you can determine (or 'fix') your position.

This chapter explains the principles of navigation. Later chapters will explain the kind of information that is printed on a marine chart (map); and how and when you actually use the techniques - although the place to really learn this (once you have understood the principles) is on a yacht.