“Marine Radar Basics”

From the Experts at The GPS Store, Inc.

Radar is one of the most important pieces of marine electronics on any boat, in part because of the variety of ways it can be used.   Its main purpose is as an anti-collision aid when navigating in darkness, fog or other limited visibility situations.  Radar also comes in handy for monitoring the position and movement of your vessel when transiting narrow passages or crowded waterways, regardless of visibility.    Radar also helps you determine your vessel’s position relative to landmasses or islands, even when they’re out of range of the naked eye.   This ability is enhanced when the radar image is overlaid onto electronic charts.     In certain situations, radar can even help you locate approaching rainstorms or lead you to offshore gamefish.


Radar offers boaters many great benefits; taking full advantage of them is up to the operator.    “While radar is certainly one of the most useful piece’s of marine electronics, it’s possibly one of the most under utilized,” said Scott Heffernan of The GPS Store, Inc.  “There are so many things radar can do, however, many boaters just scratch the surface.  Or worse yet, they don’t use their radar at all until they’re in an emergency situation,” added Heffernan.


Here are some ways boaters can optimize their radar’s performance and benefits:


Practice makes perfect.   Probably the most common mistake new radar owners make is not taking the time to practice with their radar systems during full visibility conditions.  Clear weather in broad daylight is the best time to familiarize yourself with how your individual radar set displays important targets like piers, jetties, peninsulas, the approach to your home harbor, navigation aids, moving vessels, etc.   When you can see these things with your naked eyes and your radar simultaneously, it will increase your confidence interpreting your radar display in the dark or fog.  This is also the ideal time to familiarize yourself with different Sea State adjustments to optimize performance in different conditions.


Learn the basics first.   You should dedicate time during daylight hours to become proficient operating your radar’s important navigational features.  There will always be more to learn, but not all features are created equal when it comes to safety.    Two of the most important navigation features on all marine radars are the Electronic Bearing Line (EBL) and Variable Range Marker.   In basic terms, EBL provides the bearing between you and a target on the radar, while VRM tells you the distance between your vessel and the target.   In limited visibility situations, this can be critical information, especially when tracking other moving vessels.   If the EBL to another vessel remains constant (150 degrees, for example) while the distance to that target is getting smaller, you’re on a collision course. 


Use the right range.    Many new radar users make the mistake of selecting a range (the maximum transmit/receive distance in optimal conditions) and keeping it there over a range of conditions.   The “right” range setting can change dramatically based on the conditions and what you’re trying to achieve.     If you’re navigating into a narrow inlet in the dark or poking your way through a busy harbor in a thick fog, you’ll want to see close-in targets in as much detail as possible and should select a short-range scale.   If you’re crossing a crowded shipping lane at night, you’ll want to be aware of large ships in your path from a few miles away.    If you’re navigating to an offshore island and want to verify your relative position and course to a specific point, you may want to extend that range out to 16 miles or more.  These are just a few examples.  Again, “practicing” with your radar under the many navigational situations you encounter in the day will give you the confidence to select the optimum range when you need it.


Be sensitive with gain.   A radar’s gain setting adjusts the receiver’s sensitivity, so many boaters assume more must always be better.    Having the gain adjusted too high often results in unwanted “noise” on the radar display and can prevent important targets from being seen.  As a general guide, use less gain when operating on shorter range settings, and more when looking at a longer range picture.   Adjust the gain down and slowly add more until you start to pick up noise on the display.    Then back it off just until the noise disappears.

Don’t stop learning.  While it’s important to learn the basic features first, don’t fall into the common trap of stopping the learning process once you get comfortable.    Keep expanding your horizons.  Many modern radars have a “trail” feature to better discriminate moving from stationary targets, the ability to overlay radar onto electronic charts for enhanced situational awareness, integration with Automatic Identification System (AIS) to identify ship targets on the radar, and more.   Radar empowers navigators with information beyond what’s available to the eye.   — The more you know about your boat’s radar, the more information you can get. 


For example, high-power open array radars can be used by sport fishing vessels to “see” flocks of working seabirds miles away (bird activity often indicates schools of tuna or other pelagic gamefish).   Along the same lines, experienced offshore anglers can use radar to locate groupings of other sport fishing vessels and — when integrated with bathymetric charts and GPS — obtain the location of the hot bite.  If you can pick up a bunch of boats working around a known offshore canyon or seamount, it’s reasonable to assume they’ve found the fish.


“Radars can seem complicated to the average boater, and as a result, they often become little more than an expensive adornment,” said Heffernan.  “However, much like computers, smart phones and other technologies, the more you use and trust it, the more useful it becomes to you.   We encourage boaters to use their boat’s radar on every trip, so when they actually need it, it will come naturally.”


The GPS Store sells a wide variety of radar systems from most all major manufacturers such as Furuno, Raymarine, Garmin, Simrad, Lowrance, and SI-TEX, both through its Ocean Isle Beach, North Carolina showroom and popular website.  Its trained staff is happy to help boaters select the best radar for their vessel and navigation needs,  and eager to provide advice on how to get the most out of it.  For more information, visit www.TheGPSStore.com or call customer service at (800) 477-2611.


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