DIGITAL CHARTING FOR ANGLING SUCCESS
by Ron Ballanti
 When
it comes to fishing with electronic charts, most private boaters
fall into one of three camps. There are some boaters who have a
deep understanding of their digital charts and chart plotters, and
regularly count on their high-tech capabilities to help them find
and catch more fish. We'll call them Group #1, and it's no surprise
that it's a relatively small group made up of hardcore fisherman,
charter guides, tournament anglers and the like.
At the other end
of the spectrum, you have Group #3 - skippers who've never
used a GPS/chart plotter. Maybe they're new to private boat angling
and haven't been exposed to the technology. Or perhaps they feel
that since they've done okay without one all these years, there
really isn't a need. As these wonder machines become more affordable
and easier to use, this group will become a shrinking breed.
And somewhere in
the middle you have Group #2 -- those who have a chart plotter and digital
charts on their boat, but don't necessarily use them to full advantage
when inshore or offshore fishing. Maybe they realize they're not
getting the most out of them, or maybe they don't. Either way,
given the fact that today's affordable chart plotters are finding
their way onto boats of all sizes, two things are clear: This is a large
group and it's apt to get larger. More importantly, with a little
knowledge and practice, this group has great potential for graduating
to Group #1.
Electronic Charting Basics & Terms
In the most basic terms, a GPS/chart plotter is satellite-based navigation
system that shows your vessel's position on a moving map. The
basic lat/lon data provided by the GPS is useful for navigating to or
returning to a selected waypoint, but the value of this information
to the angler is increased exponentially when laid over a detailed map
and displayed on big, easy to read screen.
What that map shows
you - and to a large extent how useful it is to the fisherman
-- depends on the level of detail and accuracy in the digital charts
(cartography) a particular machine runs. In other words, any chart plotter
is only as good as the digital charts inside.
You may hear or
read about "basemaps" or "background" maps coming
pre-loaded into handheld or fixed-mount chart plotters. These are low-detail
charts that are useful for general navigation but not well suited to
fishing. And while some handhelds have the ability to download more
detailed charts, their screen size limits their performance as a serious
fishing tool.
To get the type
of charting performance you'll want for fishing, you need to select
one of the electronic chart platforms. Generally, charts for a particular
coverage area can be purchased programmed onto small "cards"
that the user inserts into the machine. Companies also offer the option
to purchase chart CDs for planning use on home computers, with the ability
to pay to "unlock" new chart coverage areas for downloading
to your chart plotter.
 Generally,
a particular make and/or model of chart plotter is designed to operate
with a particular digital chart manufacturer's platform, and
they are not cross-compatible. Among some of the popular plotter
brands, for example, Northstar and Lowrance machines operate using
Navionics charts, as do some of the models in the Raymarine line.
Garmin plotters use the company's own proprietary Blue Chart
digital charts. Furuno offers its chart plotters in platforms that
can run either Navionics/Furuno proprietary charts or C-MAP NT+.
C-MAP charts are used in the widest variety of plotter brands, (17
North American based manufacturers and 50 worldwide) including Furuno,
Raymarine, Si-Tex, Simrad, Standard Horizon, Navman, JRC and Interphase.
As always, though, check with the plotter manufacturers to verify
chart compatibility before making a decision.
 So, it's important
that a boater considering a new chart plotter purchase thoroughly research
the cartography choices. There are many ways to do this - surf
the web fishing sites, ask around at the docks or, most importantly,
demo the machines at your local marine electronics store. Boat shows
are a great way to comparison shop, see how the digital charts look
and what kind of information they provide, and ask technical questions
about the machines themselves. You'll need to decide between a
monochrome or color display; to get the full advantage of any digital
chart platform color is the only way to go. Monochrome units are less
expensive, but there are plenty of good, affordable color units that
should really be the choice if fishing is important to you.
Two terms you might
hear are raster-based charts and vector-based charts. Raster-based charts
take scanned paper charts to create an electronic picture for display
on the chart plotter screen. In contrast, vector-based charts take the
information from paper charts to create an electronic version in digital
"layers." With the layered data in vector charts, the plotter
operator has the ability to customize the screen display to suit his
needs. For example, a fisherman might be most interested in depth contours,
fish havens or bottom composition, and he can focus on these by "turning
off" chart items like spot soundings, channels and nav aids.
The navigation software
of any particular chart plotter can "unleash" features of
the electronic charts. With the C-MAP NT+ platform, for example, anti-grounding
alarms, custom pre-set chart displays, palette displays and night screens
are some of the features accessible depending upon the plotter you're
running.
What's
The Catch? More Fish, Of Course
Most of my personal
private boat fishing experience has been with C-MAP NT+ electronic charts
on a variety of plotters, most recently an all-in-one color unit combining
the functions of GPS/chart plotter/fishfinder/radar. I'm relatively
experienced, yet I'm constantly learning new ways to use my electronic
charts to maximize my fishing time, whether I'm fishing inshore
for halibut or 50 miles off the coast for tuna and yellowtail.
Regardless of the
type of charting system you use, the basic principals of "moving
map" technology can help you catch more fish. Here are just some
examples of how Southland anglers can use their chart plotters and electronic
charts to catch more fish:
Drifting Underwater Canyons:
If you're going
to drift Redondo Canyon for makos, you want to set up a nice, long chum
slick right down the heart of this underwater gorge. A good friend whom
I fish with regularly uses his C-MAP Pro Angler contour charts to do
just that. He'll set up a quick test drift first, and watch his
boat's drift track on the screen. Then, with a better idea of
what the wind and current is going to do, he can put his chum slick
right down the heart of the canyon to intercept cruising makos. And
seeing his boat moving on the screen makes it easy to make small adjustments
if needed. Less wasted time equals more effective fishing.
Mark Your
Hookups:
When you're drifting or trolling, take the time
to enter each strike or hookup as an event on the plotter screen. Over
a the course of a day (or a season) you'll have a good "picture"
of where you're scoring, and patterns often emerge. Like a treasure
map, you'll see that "X marks the spot" where the
fish have been biting. Focusing your efforts in these areas should increase
your success. I've seen this technique work on everything from
tarpon in Florida to halibut on the flats to albacore on the offshore
banks.
Note the
Life Zones:
If I'm running offshore for a day of trolling,
I'll mark any significant temperature breaks of life zones I pass
on the way out. Likewise for places that look "fishy" -
with bait, birds or kelps -- but may not produce right off. Over the
course of a day you can see patterns, and return through these areas
on the way back.
Target Your Trolling:
For many, offshore trolling for
tuna and albacore is a game of chance. They may start off at the 181
or the 209, but once they arrive they just troll around with out a plan.
Using my C-MAP offshore contour charts, I can target my trolling along
a specific depth curve, underwater ridge or high spots that create upwellings
and currents that can concentrate pelagic species.
Whack the
Weeds:
Finding that magic, tuna or yellowtail-laden paddy isn't
always a matter of luck. Mark each significant paddy you find on your
plotter screen, even if it isn't holding. Seeing them over a map
of the ocean floor can highlight useful patterns - paddies often
form up along temp breaks or current lines that tie relate to a specific
bottom contour or structure. This will help you search in areas that
are more paddy-prone, increasing your chances of finding the mother
lode of fish.
These are just a
few examples of ways that a dedicated chart plotter and digital charts
have helped me. Start practicing and learning, and you'll come
up with many more. Once you get dialed in to fishing with electronic
charts, don't neglect to update them once a season. Not doing
so is "penny wise and pound foolish." You can be missing
not only important navigational changes (such as new or moved buoys,
channels or hazards) but also useful fishing information. For example,
recent updates to my C-MAP chart card have included the Channel Islands
MPA fishing closures boundaries (I never have to wonder if I'm
breaking the law) and C-marina charts that provide extra detail and
information when I visit or overnight in a new harbor.
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