Seeing everything that’s around you at night makes you feel more confident while cruising, and that’s just what radar (radio detection and ranging) is: your sight when your eyes are blind.It shows you what’s out there and tells you how far away it is. Ask a group of experienced boaters what they rely on most at night — besides their own eyes — and most will say radar.
While a chart plotter shows fixed objects, radar can show you just about everything above the water’s surface, including other boats. Marine radar has been around for decades, but today’s radar systems are more
refined, easier to use and less power hungry than ever before.
Traditionally, radar loses effectiveness at very close range due to a phenomenon called “main bang,” which results in a blob in the middle of the screen that obscures targets close to the boat.
However, newer radars such as the Lowrance and Simrad Broadband units (navico.com) don’t have the main bang, so they can read an object very close to the boat. While such units are not very effective at ranges beyond a few miles (the new Simrad Broadband 3G radar has greater range), the close-in target detection feature can be useful when cruising crowded waters in the dark.
Most multifunction displays, such as the Furuno NavNet system, can also be configured to “overlay” the radar readings on an electronic chart display. This provides an enhanced view of the surroundings at night and also allows you to more readily interpret the radar images, relating them immediately to objects on the chart.
Plus, you know any radar target that is not on the chart is most likely another boat or barge, though it could also be an off-station buoy.
You can also set the radar guard zone, but in crowded waters with lots of fixed objects, the guard zone alarm tends to sound too frequently. This feature is most helpful when cruising open water far from the clutter of the harbor.