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Chapter 8
Dead Reckoning, Piloting, and Electronic Navigation
Introduction
In this chapter, you will learn how to keep track of the ship’s position.
It is extremely important that the QMOW be able to quickly estimate the
ship’s position at any time. Dead reckoning (DR) is one of the most
basic and widely used methods of navigating. Dead reckoning is always
employed any time a vessel is under way.
The primary reason for using dead reckoning is that the navigator may
at any time give a reasonable account of the ship’s position without
having to take sights or obtain a position from other means. In many
places on Earth, a vessel may get beyond the range of today’s
sophisticated navigational aids and have to rely on methods as old and
time tested as the DR. Many vessels have been under way for weeks at
a time without having made a landfall or having any other contact with
shore and have still come within a very few miles of the desired
destination using only a carefully maintained DR plot.
The practice of maintaining a DR plot will be the first task we focus on
in this chapter. Piloting will be the second main focus of this chapter.
Perhaps you recall from chapter 1 that the QM uses visual aids to
establish the ship’s position when piloting. Electronic navigation uses
several pieces of electronic equipment. State of the art equipment is
often used. Currently, the Navy’s cutting edge electronic navigation
equipment is the WRN-6 Satellite Navigation Set.
Objectives
The material in this chapter will enable you to:
Identify the primary reason for using dead reckoning, and match
plotting instruments and tools with their usages.
State how you obtain true or magnetic course using the compass
rose.
State the purpose of a course line, and identify the proper method of
labeling course lines.
State the two factors considered when using the dead reckoning
process.
Match the plotting symbols with their appropriate meaning: DR, EP,
visual fix, and electronic fix.
Calculate speed, time, and distance problems using the formula D =
S x T, the nautical slide rule, and the 3-minute rule.
List three methods used to measure a ship’s speed through the water,
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