Radar for Mariners, Revised Edition - Softcover

Burch, David

Softcover

ISBN 10: 0071830391 ISBN 13: 9780071830393

Verlag: International Marine/Ragged Mountain Press, 2013

Inhaltsangabe

Become an Expert Small-Craft Radar Operator

Nothing beats radar for guiding your boat through the darkest night or the thickest fog. Radar enables you to plot a fix from just a single buoy or landmark, and it is the only navigation tool that tells you not just where you are, but who else or what else is out there with you. Today's smaller, affordable, efficient radars make more sense than ever for sailors and powerboaters.

Adopted by the American Sailing Association for their radar course and used by professional and recreational radar training schools around the world, this complete, in-depth manual shows you how to:

• Choose the best radar model for your sailboat or powerboat
• Install, adjust, and operate your system
• Interpret the images on your radar screen
• Pilot your boat and track the movements of vessels around you
• Use radar to track and avoid squalls, outmaneuver competitors in a yacht race, and other specialized tasks
• Interface your radar with a digital compass, GPS, or electronic chart

"This book will turn you into an expert on small-craft radar operations. It covers everything--radar choice, installation, use, and how to interface with your electronics. Very comprehensive!" -- Boat Books

"Stands out among other books on the subject . . . an excellent introduction to radar." -- Power Cruising

"Radar is an electronic tool, the operation of which takes much more interpretation than any other--too little knowledge can be just as dangerous as none. Radar for Mariners helps you understand how radar works, explains its limitations, and shows you how to get the full use of radar's functions. This book should show up on the radar screen of anyone with radar--or contemplating getting one. I can't wait to go to my boat and stop playing with my radar and start using it." -- Good Old Boat

Über diesen Titel

Über die Autorin bzw. den Autor

David Burch, the director of the Starpath School of Navigation in Seattle, Washington, has been teaching navigation and seamanship since 1977. He has logged more than 60,000 sea miles, including three wins in the trans-Pacific Victoria to Maui yacht race. He is the author of nine books on marine navigation, including Emergency Navigation (International Marine, 1984), and his magazine articles have appeared in Cruising World, Ocean Navigator, Sailing, and Sea Kayaker. He holds a U.S. Coast Guard Master's license (100 tons). He is also a past Fulbright Scholar and holds a PhD in physics. HOMETOWN: Seattle, WA

Auszug. © Genehmigter Nachdruck. Alle Rechte vorbehalten.

RADAR FOR MARINERS

By DAVID F. BURCH

McGraw-Hill Education

Copyright © 2013 David F. Burch
All rights reserved.

ISBN: 978-0-07-183039-3

Contents

Preface
Acknowledgments
Part One WORKING KNOWLEDGE OF RADAR
Chapter 1. HOW RADAR WORKS
Chapter 2. OPERATION AND "TUNING"
Chapter 3. INTERPRETING THE RADAR SCREEN
Chapter 4. RADAR FOR POSITION NAVIGATION
Chapter 5. RADAR PILOTING
Chapter 6. RADAR FOR COLLISION AVOIDANCE
Part Two BEYOND THE BASICS
Chapter 7. INSTALLATION, SPECIFICATIONS, AND PERFORMANCE
Chapter 8. SPECIAL CONTROLS AND FEATURES
Chapter 9. FALSE ECHOES AND INTERFERENCE
Chapter 10. ADVANCED NAVIGATION AND PILOTING
Chapter 11. RADAR MANEUVERING
Chapter 12. RADAR AND THE NAVIGATION RULES
Chapter 13. LOOKING AHEAD
APPENDIX
Glossary
List of Abbreviations
References
POSTSCRIPT: HIGH-DEFINITION (HD) AND BROADBAND RADAR
INDEX

CHAPTER 1

How Radar Works

Radar (radio detection and ranging) is an onboard electronic navigationinstrument that measures the range and bearing of landmasses and vessels in itsvicinity. It works by sending out a rotating beam of microwave pulses anddetecting the pulses that are reflected back from objects around it. It workslike a depth sounder, pointed toward the horizon rather than the bottom. As witha depth sounder, what we see on the radar screen are only electronic blips orechoes of the targets, not realistic representations. Also like a depth sounder—ora flashlight scanning a dark room—the radar beam only "sees" what is in viewof the beam at the moment. The radar's internal display electronics must paint apicture on the radar screen as the beam scans the horizon, refreshing it every 3seconds. It takes some practice to read a radar screen and interpret what isreally out there. We cover this in Chapter 3. As we shall see, some objects arebetter radar reflectors than others, which gives rise to the term radar target.A good radar target is one that sends back a strong, well-defined image to theradar screen. Figure 1-1 illustrates schematically how a radar operates.

Isolated targets such as other vessels, large buoys, islets, or drillingplatforms are easier to interpret than large, irregular landmasses. At longerdistances, isolated targets appear as simple dots or small line segments. Asthey get closer their target sizes increase, but unless an object is big andfairly close, the size of the echo on the radar screen (of a ship or buoy, forexample) is not a measure of the actual size of the target. This concept isexplained further in Chapter 3. The image or echo of a target seen on a radarscreen is sometimes called a blip.

The basic components of a radar system are an antenna, the radar display unit,and a power source—a typical radar consumes 30 to 40 watts when transmitting.The radar display unit includes a radar screen and a set of controls (knobs,buttons, and sometimes a track ball). There are sophisticated electronics inboth the display unit and the antenna, and it is generally most efficient tohave a professional electronics technician install and calibrate the systembefore use (installation options are discussed in Chapter 7). After properinstallation it runs dependably and requires little attention as a rule,although basic performance monitoring as discussed in Chapter 13 is alwaysprudent. Radar is a powerful broadcasting device, so an FCC (FederalCommunications Commission) Ship Station Radio License (or internationalequivalent outside the United States) may be required in some cases (see Chapter7). If you already have a license for a marine radio, the radar can be added toit without a new license.

What you see on the radar screen are your surroundings to a maximum distanceequal to the selected range setting. The word range is used many ways innavigation, but for radar, it simply means the distance from your vessel to theradar target. Typical small-craft radars have maximum ranges of 16 to 36 miles—shipradars extend out to 72 miles or more—but we have to cover more backgroundbefore we can appreciate the significance of these numbers. On the plan viewused on radar display screens, your vessel is in the center of the screen. Deadahead is usually straight up (at the top of the radar screen), your surroundingsto starboard are in the right half of the radar screen, your port side is on theleft, and aft at the bottom. Modern radars offer options to this display mode,but this head-up mode is the most fundamental and still the most common insmall-craft radar. Head-up display is illustrated in Figure 1-2, which shows aradar image overlaid on the chart region it is viewing. It is similar to theschematic view of Figure 1-1, but with real data.

Radar units are often loosely referred to by their maximum range. A "32-mileradar" has a maximum range of 32 miles but can also be set for 24 miles, 16miles, 8 miles, and so on. In the past (as well as in many units today), theavailable range options were fixed values. In some modern units, the user canchoose any range desired up to the maximum range of the unit. Also in the past,radar screens were circular, so if you selected a display range of 6 miles, thecircumference of the display was 6 miles away in all directions. Most modernradars screens are rectangular, with the display shifted slightly toward thebottom to show an extra ring forward. Today, a range setting of 6 miles willmore likely mean that you can see 6 miles to the right, left, and aft, andapproximately 7 miles dead ahead, as can be seen in Figure 1-3. In all modernunits, however, there is always an Offset function that lets the userarbitrarily shift the center location for longer looks in any direction. This iscovered in Chapter 8.

RANGES, BEARINGS, AND BUOYS

To navigate from what we see on the radar, we need numerical values of theranges and bearings to the various targets shown on the radar screen. The veryconvenient, electronic way of measuring these values with radar is one of theprimary virtues of the instrument.

Suppose we are looking for a buoy about 2 miles ahead on the starboard bowaccording to the chart and our GPS position. The first step in locating thisbuoy on the radar screen is to select the appropriate range scale. If the rangescale were set to only 1 mile, we would not see the target because it is morethan 1 mile away. When we increase the Range (by just pushing a button orturning a knob) to the 3-mile scale, however, we should see a target abouttwothirds of the way out from the center in the top right quadrant of thescreen. If we increase the Range again, to 6 miles, the target should remain atthe same relative bearing on the screen, but will now be nearer the center, justone-third of the way out, and will register as a smaller blip. If our rangeoptions were just 3 or 6 miles, the 3-mile scale would be the better choice.Generally the smallest range that shows the target of interest will give thebest results for range and bearing measurements. This...

Details zur Ausgabe

• Verlag: International Marine/Ragged Mountain Press
• Erscheinungsdatum: 2013
• Sprache: Englisch
• ISBN 10: 0071830391
• ISBN 13: 9780071830393
• Einband: Taschenbuch
• Anzahl der Seiten: 254
• Kontakt zum Hersteller: MCGRAW-HILL EDUCATION TAB; service@mheducation.com ; ; 1221 Ave of the Americas; New York; 10020-1095; USA
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