WHAT TO LOOK FOR IN A GPS/CHARTPLOTTER
 When they
first came on the scene in the late ‘80s, GPS/chartplotters
were usually limited to commercial vessels or high-end recreational
yachts and fishing boats. Like most consumer electronics, over
the years electronic navigation equipment has gotten smaller,
faster, better, easier to use and more affordable. As a result,
GPS/chartplotters are found today on just about every type of
vessel, from bluewater cruisers to open skiffs.
With so many
choices out there, it can be daunting for any boater – especially
those new to the sport – to select and purchase a chart
plotter. Even at today’s affordable prices, a GPS/Plotter
represents a substantial investment. And it’s a piece of
equipment you’ll be counting on every time you cast off
from the dock, whether you’re a sailor, a cruiser or a fisherman
– so you need to make sure you’ll be happy with it
over the long run.
Making the
“right” choice is all about selecting a GPS/chart
plotter that fits your boat, your budget and the type of boating
you do.
Chartplotter Basics and Terms
Described in the
most simple terms, a GPS/chartplotter is an electronic navigational
system that uses a receiver that hones in on signals from a network
of Global Positioning System (GPS) satellites, then
processes this data to fix your position anywhere in the world. When
used with electronic cartography, it then displays and tracks your vessel
on a digital marine chart, providing this information on either a Cathode
Ray Tube (CRT) or Liquid Crystal Display (LCD).
As a navigation tool, this provides you with graphic and range/bearing
information to any waypoint (destination) you choose,
helping you accurately steer your boat to any cove, island, harbor,
fishing spot, anchorage, etc. You can link series of waypoints into
routes, allowing you to accurately navigate over long distances around
points of land or up twisting river channels and waterways.
There are several
variations of GPS receiver types, including standard GPS,
Differential GPS (DGPS) and Wide Area Augmentation
System (WAAS).
Standard GPS usually
has a repeatable accuracy of 30 meters or less. Repeatable accuracy
is how close it will put you to any position you’ve “saved”
in the GPS’s internal memory by hitting an event key or entering
latitude/longitude coordinates. This level of accuracy is more than
enough for many navigational uses; several choices are available to
provide increased position accuracy.
WAAS-enabled GPS
receivers can receive a more accurate satellite signal without the need
for a separate antenna. This system – which was developed for
aviation use – increase position accuracy to 3 meters or less
and is available on a wide range of units from high-end commercial GPS/chartplotters
down to portable handhelds. With SA (Selective Availability) turned
off, DGPS has become no longer needed.
Choosing a chartplotter
also means choosing the type of electronic charts you’ll be using
and selecting the electronic chart platform, or cartography.
Many navigators favor the accurate, vector-based NT+
electronic charts from C-MAP. Since vector charts are created in digital
“layers,” this provides the capability to customize the
screen display to suit the needs of the navigator. Certain items on
the chart may be more important to the fisherman (i.e. wrecks, bottom
composition or depth contours) than would be to somebody on a long-distance
cruise (i.e. spot soundings, nav aids and channel entrances). In contrast,
raster-based charts take scanned paper charts to create an electronic
“picture” for display on the chartplotter screen.
The power of the electronic charts is “unleashed” by the
navigational software of the system. Course-Up and Heads-Up displays,
anti-grounding alarms, custom chart display views (pre-set chart screens),
palette displays and night screens are just a few of the features that
make vector based electronic charting systems the choice of boaters.
Another factor in favor of the C-MAP NT+ charts is they are compatible
with the widest range of chartplotter brands (some 50 manufacturers
worldwide as of this writing).
Choices,
Choices, Choices
So, now you have a basic understanding of how chartplotters work and
the wide array of options available to you. Armed with this information,
it’s time to make some choices about what type of system will
work for you and your boat.
Of course, one of
the first things you’ll have to figure out is what you want to
spend. Fortunately, there are many excellent choices from the low end
to the high end of the budget spectrum and your money will buy more
features and options than ever before. The trick, therefore, is deciding
what features are important to you and spending your money on features
that you’ll actually use – today and in the future. Remember,
as you become more familiar with electronic navigation you’ll
want to do more with your GPS/chartplotter.
Size and
Mounting Location
One of the primary considerations is the overall physical size of the
unit and where you intend to mount it. Many boaters opt to bracket mount
the unit on top of a console or helm station, bracket mount it in an
overhead electronics box or even install it as an overhead mount. This
allows you a lot of latitude in placing the unit in your best line of
sight from the helm station, as well as providing the ability to change
the viewing angle if needed for better screen clarity in changing light
conditions.
Most chartplotters
can also be flush mounted into the console, helm station or other panel.
This makes for a very clean, professional looking installation, but
has some drawbacks. It’s a more complicated installation that
involves cutting or customizing your helm station. You may not be able
to place the unit in your best line of sight from the helm, and you
cannot tilt or rotate the unit for better visibility in changing light
conditions. If positioned and installed properly, however, flush-mounted
units can deliver excellent performance. Having it at arms length is
the key to a good installation, as you will want to be able to have
instant access to the system while at the helm.
Get the Big (and Best) Picture
Whichever type of installation you choose, it’s important to select
a plotter that fits properly on your vessel. In general, it’s
best to select the largest chartplotter – as long as fits your
boat and your budget. The larger the display size, the happier you’ll
be over the long run with your chart plotter’s performance. C-MAP
NT+ electronic charts offer a high level of detail and data for navigating
and fishing, and the larger screen will make this data all the more
useful to the boater.
You’ll also
have to consider the display type. Once the industry standard, CRT units
(which operate much like home television screens) have mostly been phased
out except for large commercial applications. Chartplotters built with
LCD screens offer several advantages, including slimmer, smaller machines
overall that let you maximize screen size and far less power draw.
Monochrome LCD screens
provide chart detail in varying shades of gray. Units with monochrome
screens are usually found in lower cost chart plotters and while useful,
don’t take full advantage of what today’s electronic charts
have to offer. And with recent advancements in color LCD displays, you
no longer need to buy a large chartplotter or spend a ton of money to
get a great color display with excellent resolution and readability.
One of the areas
where color LCD plotters have really improved is screen readability
in direct sunlight. This was once a notable drawback of LCD screens
in general and color LCD screens in particular. Today, many manufacturers
offer affordable units that provide color LCD displays with bright,
colorful screens that can be read in even direct sunlight. Different
manufacturers address this issue in different ways. Some utilize filters
and brightly lit LCD displays to keep direct sunlight from “washing
out” the display. Others use transflective technology, which basically
acts like a reflector using the sun’s own light to increase the
brightness of the display in sunlight. The more light you shine on the
display, the brighter it shines back at you.
At boat shows around
the country, manufacturers often tout their sunlight readable displays
by training big spotlights on chartplotter screen. Still, ask around
and check with other boaters on your dock to get a feel for how the
brand you’re looking at performs in actual outdoor conditions.
Another performance
issue to consider is processor speed. This determines, among other things,
how quickly the chart display “redraws” itself as your position
moves, when you change the display mode or when you zoom in or out.
If a plotter is slow on the re-draw, you’ll be generally dissatisfied
regardless of what other features it may offer.
Fortunately, processor
speed is another area that has seen great improvements over the last
several years. Many of today’s plotters are so fast as to offer
nearly instant screen re-draws. Still, on this point it’s best
to comparison shop and actually demo the units you’re considering.
You can do this on the water (if you find somebody with a comparable
unit) or you can often test them on the boat show floor (even in demo
mode, you should be able to gauge how fast the machine responds and
how quickly the chart display redraws.
One For
All, Or Stand Alone?
You also have to decide if what you really want is a stand-alone chart
plotter or an integrated system capable of giving you navigation and
chart data, fishfinder, radar and more on once display. Which way is
the “right” way? That depends on your boat, your budget
and your needs. There are some obvious advantages to having everything
in one “box.” For starters, what used to take three or more
separate units can now be accomplished with one shared display, making
installation easier on boats with limited electronics space. These units
offer the capability to display just one function at a time (say, electronic
chart for example) or multiple functions (chart, echosounder and radar)
in a split screen or overlay presentation. They are designed to offer
a variety of useful display options that let you focus on the information
that is important to you. And in contrast to what you might think, once
learned, they are not overly complicated to use and operate.
If there is a negative
to multi-function systems, it has to be this: In the unlikely event
that the system fails while on the water, you may lose all of your electronics
functions. This means no fishfinder, no chartplotter, no GPS, no radar.
While this prospect alone is enough to dissuade some boaters, in practical
application this is rarely -- if ever -- a problem. Still, you may want
to consider a redundancy for your most important function, such as having
an extra small color fishfinder as a standby (if fish location is your
most important goal).
Choice Is Good
As you can see, today’s boater is faced with myriad choices when
selecting a GPS/chartplotter and marine electronics systems as a whole.
As a boater, you can do one of two things. You can be overwhelmed by
the choices, and end up selecting something in haste that will not meet
your long-term needs. Or, you can look at it this way – with so
many choices, the boater who does his homework and considers his needs
carefully will eventually find the ideal match. The technology and performance
of marine electronics is more advanced that at any time in history –
and it’s only going to get better. There are many great resources
at your disposal, including the Internet, making it easy to gather data,
compare products and make informed decisions. BoatersWorld.com offers
a huge selection of state-of-the-art GPS/chartplotters, as well as a
wide variety of chart cards from C-MAP and other makers of electronic
cartography – all available for instant purchase with the click
of a mouse. Plus, you’ll pay no sales tax, and shipping is free
for orders over $100. To browse, obtain more information or buy online,
click here.
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