By Capt. Ann Kinner
The view from my office this morning is classic San Diego: light
haze over the bay and around the skyline, Mexico’s mountains
outlined in the distance, clear sky overhead. It would be a very
pleasant day to be cruising along the coast. Visibility: miles!
If I were, in fact, prepping the boat to get out of the slip, one
of the first instruments I would be checking would be my radar, and
I’d have it turned on for the duration of the voyage, clear sky or
During the run, I’d be adjusting the range – half a mile inside
the bay, maybe a mile and a half in the approach to Point Loma,
maybe six miles if I were headed for Ensenada through the Coronados.
Anyone who’s spent much time on the water in Southern California
has been in fog so thick visibility was down to maybe a boat length.
Anyone who’s run a boat at night in San Diego Bay or near the Los
Angeles harbor knows the confusion of lights along shore that mask
lights on the water.
The challenge for many boaters is translating the radar image
into meaningful information in the midst of all the fog and
confusion. Let me suggest a good book.
The Good Book
The Radar Book, by Kevin Monahan, is a clear, relevant lesson
on radar for just about anyone interested in the subject. After a
very short introduction covering the history of the device, Monahan
presents a wonderful extended sequence of images that immediately
clarify and relate the blobs on the radar screen to the details on
the chart, and the view from the bridge.
With a minimum of technical language, Chapter One takes the
reader on a trip from Victoria Harbour around the southeast coast of
Vancouver Island through Sidney Channel and into Port Sidney. Each
step of the voyage is illustrated with a direct comparison of the
radar image and the corresponding chart, from the point of view of
The captions cover what appears and why, from radar shadows, to
sea clutter, to buoys and boats. Just reading these captions and
studying this sequence will teach you enough about radar to make you
comfortable interpreting what’s on your own screen.
Adjustments And Controls
Chapter Two gets into the various adjustments, and the oddly
named tuning controls. Monahan offers a step-by-step sequence from
turning the instrument on to getting the best possible – and most
useful – image. He explains "gain" and "sea clutter."
He shows the use of range rings and "variable range marker" to
find your position on a chart. Then Monahan provides an extensive
lesson on the use of radar to avoid collision, which may be the
ultimate best reason to use radar: perfect visibility!
If you only read these two chapters, you’ll be ahead of the
screen. If you read the rest of the book, you’ll truly understand
why radar is at the beginning of my tool list.
Chapters Three and Four cover the technical parts — displays,
scanners, frequencies, beam width, horizon, reflectors, all the
hardware involved. Chapter Five offers an extended discussion on
optimizing the display.
Chapter Six talks about interconnecting radar and navigation
equipment, including computers. The balance of the book covers the
use of radar in specific situations, from poor visibility to heavy
seas, and, finally, the kinds of things that can go wrong and what
to do about them.
On The Side
All through the book are side notes, comments that fall outside
the immediate text but that further explain or illustrate some
critical part of the total radar package. For example, why does a
cargo ship make a good target, while the shoreline around Catalina
makes a poor one?
Why does the width of the radar beam matter? Should you keep the
old (still-working) radar or get a new one?
At the end are an appendix on technical specifications, a short
glossary for quick reference, and a bibliography with a list of
Internet resources for information specific to various radar
Beyond its information value, this book was an interesting book
to read. I can recommend it for anyone who uses radar, would like to
use radar, or is simply curious about the concept of seeing through
The Radar Book is available at is available at Seabreeze
Books and Charts in San Diego (www.seabreezebooks.com)
— Arizonans welcome! — and at many other fine nautical stores.