Practical Navigation for the Modern Boat Owner: Navigate Effectively by Getting the Most Out of Your Electronic Devices

by Pat Manley

Overview

The modern sailor is an electronic navigator. New boats come stacked with GPS, chartplotters and radar, on a bewildering array of screens and displays. With this book learn how to navigate using all of these electrical devices. Practical Navigation leads you through all the aspects of boat navigation in a logical order, using a combination of modern and traditional methods. This practical approach ensures that although modern electronic methods remain at the forefront, readers will never lack in knowledge to navigate their boat safely in any circumstance. Topics covered include GPS, the shape of the Earth, finding your position, passage planning, radar and personal computers.

Product Details

ISBN-13:	9781912177516
Publisher:	Fernhurst Books Limited
Publication date:	04/14/2008
Sold by:	Bookwire
Format:	eBook
Pages:	200
File size:	60 MB
Note:	This product may take a few minutes to download.

About the Author

Pat Manley is a keen sailor and one of Practical Boat Owner magazine’s team of experts, answering readers’ questions. He is author of Fernhurst Book’s Simple Boat Maintenance, Essential Boat Electronics, Diesels Afloat, Electrics Companion and Diesel Companion.

Read an Excerpt

Constructing a Route

These days we probably think of a route defined by a series of waypoints, places to which we wish to go in the process of getting from one place to another. The term waypoint is relatively modern, stemming from the need to find the latitude and longitude of a point so that we could then enter it into a navigation receiver’s processor via a keyboard. When navigation was less sophisticated, we would put some lines on the chart and plot our position to endeavour to keep as close to track as possible. There was no need to extract and write down any latitude and longitude at all unless we were using a sextant.

These days we should be able to enter into the ‘navigator’ the coordinates (latitude and longitude) of any position that is on our ‘way’. These are the waypoints.

The process will differ according to the type of ‘navigator’ we are using; GPS receiver or GPS chartplotter.

Using Second-Hand Waypoints

You can buy books of waypoints. Also pilot books, almanacs and boating magazines list waypoints. I never use waypoints that I have not plotted myself, and I never join waypoints from a list to form a route, unless I have inspected the area on a recognised chart, paper or electronic. What is the point of using waypoints, the author of which states that you use them at your own peril and that they should not be used for navigation?

A Route for Use with a GPS Receiver

Here, our starting point is a paper chart on which we can draw a complete route. It may not have sufficient detail in areas where we are close to danger, but we can see the whole route on one sheet.

Choose your route so that it is as short as possible, but avoids passing too close to any possible hazard. It’s possible that you may have to adjust the route when you look at smaller scale charts where the route needs to be inspected more closely.

Do not use the actual position of navigational marks as waypoints. GPS can be so accurate that you might collide with the buoy, and if other navigators also use the same mark, you may collide with their boat. Aim 100 metres or so off.

Let us construct a route from Annapolis to St Michaels in the Chesapeake. We’ll need a chart with a scale of around 1:1 25 000 for the overview and charts of a scale of around 1:2 500 for each end where we need more detail.

Starting at Annapolis we can put the first three waypoints on the large-scale chart, before moving to the small-scale chart to add the next seven waypoints.

Now we’ll need to use the large-scale chart for St Michaels to put the rest of the waypoints in place.

Now we’ll need to use the large-scale chart for St Michaels to put the rest of the waypoints in place. Once you have a safe route, mark the waypoints and determine their coordinates. There’s no standard symbol for a waypoint, as there are other navigation details, such as position. Many navigators, however, use a square with a cross in the middle.

Measure the distance and direction of each leg and note these down on a ‘plan’. It’s a good idea to use a printed ‘pro forma’ for this, or on the route-planning page of your navigation logbook.

Table of Contents

Cover Points     xi
Foreword     xiii
Introduction     xv
The Global Positioning System     1
How Your GPS Receiver Tells You Which Satellites It Can See     2
How GPS Works     3
Accuracy of the Fix     4
GPS Blackout     5
Deliberate Interference     5
GPS Is Line of Sight     5
Selective Availability     6
Differential GPS     6
Wide Area Augmentation Service     6
Switch-On Delays     7
Measurement of Speed     8
Measurement of Course     8
Measurement of Heading     9
Errors in COG and SOG     9
Our Address on the Earth's Surface     11
The Equator     12
Latitude     12
Greenwich Meridian     12
Longitude     12
Our Address     13
International Date Line     13
Measurement of Latitude and Longitude     13
Distance and Direction     14
Direction     16
The Flat Earth     19
The Spherical Earth and 'Map Data'     20
Chart Errors     22
Chart Scale     24
Measuring Latitude and Longitude     25
Chart Symbols     26
The Magnetic Compass     29
The Earth's Magnetic Field     30
Steering Compasses     30
Compass Deviation     31
Compass Correction     31
DIY Compass 'Swing'     31
Fluxgate Compasses     33
Constructing a Route     35
Using Second-Hand Waypoints     36
Loading the Route into the GPS     38
Constructing a Route on an Electronic Chartplotter or PC     38
Tides     39
Tidal Heights     39
Tidal Flow     50
Finding the Value of the Tidal Flow     52
Boat Speed     57
Speed over the Ground     57
Speed Through the Water     58
Measuring Speed Through the Water     58
Log Errors     58
Depth Sounders     61
How They Work     62
Depth Units     62
Calibration     62
Depth Alarms     63
False Echoes     63
Fishfinders     63
Finding Position     65
GPS      65
Other Methods     66
Position Lines     67
Fixing Your Position Using Position Lines     69
Errors in Position Lines     70
How Far Can You See?     71
When All Else Fails     72
Chartplotters     73
Passage Planning     77
Overview     78
Detailed Plan     79
Just Prior to Departure     80
Passage Planning - Procedure     81
Preplan     81
For the Planned Day of Departure     81
Passage Making     81
Passage Grid     86
Approach 'Spider's Web'     86
Compass Rose as a Waypoint     87
Unmarked Danger as a Waypoint     88
Clearing Bearing     88
Pilotage     89
Who Does the Piloting?     90
Means of Pilotage     90
International System of Buoyage     90
International Buoyage - All Areas     92
Planning     97
The Basics of Preparing a Pilot Plan     97
Making a Pilotage Plan     98
Working as a Team     101
Automatic Identification System     103
What is Automatic Identification System?     104
How Does AIS Work?     104
Class A AIS     104
Class B AIS     104
AIS Displays     105
The AIS Display on a Chartplotter     106
AIS Class B Transceiver     107
Radar     109
How Radar Works     110
Navigation Using Radar     113
Pilotage Using Radar     114
Radar Overlay on a Chart Plotter     121
Setting up Your Radar     121
Radar Used for Collision Avoidance     122
Autopilots     125
Types of Autopilot     125
Using the Autopilot     126
Personal Computers     129
What Type of PC     130
What Make of Chart-Plotting Software?     130
What Type of Electronic Charts?     131
Electronic Charts for PC Based Chartplotters     132
Selecting the Software     133
Constructing a Route     134
Sailing Yacht Route Planning     135
Sending the Route to the GPS     137
AIS on a PC     138
Radar on a PC     139
Navtex on a PC     142
Tides on a PC      142
Connecting to the Boat's Systems     143
Deduced Reckoning and Estimated Position     145
DR Navigation     146
Estimated Position     146
Leeway     148
Error in EP     148
EP with Multiple Headings     148
Course to Steer     149
Where Do You Want to Go?     150
What Time Interval Do You Choose?     150
Draw in the Tide     151
Draw in the Boat Speed     151
Ground Speed     152
Comparison with EP     153
Tidal heights and Tidal streams     155
Atmospheric Pressure Corrections     156
Tide Tables     156
UKHO Tidal Predictions     156
SHOM Tidal Predictions     159
Tidal Streams     161
Tidal Planning and Plotting     165
A Long Passage Using a Single CTS     165
Where will the Tide Take You?     167
Credits     169

Editorial Reviews

"A useful companion for the modern sailor who wants to navigate their way through the seas.” (Boat Mart)
“Pat Manley gives the reader a detailed overview of all the systems currently in use, from GPS to AIS, and describes how each system works, how to use it and how to get the best out of it. However, the author highlights the danger of over-reliance on such electronic tools and points out some of their shortcomings. He also stresses the importance of having at least some knowledge of traditional navigation.” (Noonsite)

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