Marine Electronics: Using Marine RADAR

Marine radar (Radio Detection and Ranging) is used to detect objects and their position relative to your location. It works by sending out a radio signal. When the signal hits an object it is reflected back to the radar unit which can then calculate the bearing of the object.

A marine radar device is an essential navigation aid for boaters. It is useful for detecting boats, birds landmasses, and weather systems even when visibility conditions are less than favorable.

Marine Radar: Top Features to Look For

The two most important features of any marine radar device are the transmitter power and the beam angle. Power can range from 2 to 4 Kilowatts. The higher the power, the better your transmitter can see through fog and rain and the further the signal can reach. Power is a factor in how well your radar does in bad weather. Blinding rain can cause low power marine radar to be less than effective.

Beam angle is determined by the size of your marine radar's antenna. A long antenna will produce a narrow beam that gives good discrimination between objects close together. A short antenna has a wider beam angle allowing the radar to scan a wider area at one time.  Antennas are often customizable or configurable and can be purchased separately.

Guard Zone Alarm
Most marine radars allow you to set a guard zone around your boat. You specify the safety distance and set an alarm.  If your vessel detects a buoy, landmass or other obstacle within the proximity of your guard zone, the alarm sounds.

Split Screen Displays
Split screen displays allow you to monitor objects close to your boat and objects further away at the same time. This feature is useful, among other things, for navigating buoys as you leave the shoreline while heading out towards a more distant spot.

Best Use of Marine Radar

One of the best features of marine radar is its ability to determine where you are with respect to where you were a few minutes ago. This "echo trail" feature can be used to determine how well you are navigating an obstacle as well as how well you maintaining the bearing you have set for your vessel. The echo trail is displayed on the radar's display screen so you can quickly assess visually what is going on.  

Integrated Marine Radar and GPS/Chartplotters

Marine radars are fairly expensive; many units run in the thousands of dollars. It is a good idea to talk with other boaters and see what they are using and what features they like before committing that much money. To get more bang for the buck, look for marine radars that are already incorporated into other marine electronics such as GPS units and Chartplotters. Integrating your marine components reduces the complexity of your visual displays and reduces overall cost of items.  Even though sometimes you have to compromise with the features of each component offered in the integrated package, integrated marine radars offer good value for hobbyist boaters.

Tracking other vessels with Marine Radar Systems

Whether you are at sea on a relaxing sailing holiday, engaged in a commercial fishing trip hundreds of miles off shore, or carrying freight from one location to another, keeping track of any other objects such as other boats and larger ships in the area is essential if you want to maximize your safety on the water.  By using one of the latest generation of marine radar systems, you will be able to take advantage of a number of technologies that make tracking other vessels easier than ever, and even mark their positions and routes on the screen.

The sea can be a cruel mistress, and a change in conditions can come on pretty much instantly.  One minute you can be scudding along over practically smooth water, the next, a fog can come down obscuring the world around you, and you can be battling against thirty foot waves and high winds.

This ever changing nature of the ocean means that as conditions change you can face different challenges that can impinge upon your safety.  The key to ensuring that you remain as safe as possible is to remove as many of the factors that can change from the overall picture.

Other vessels are often the biggest threat any seaman can face.  Smaller boats in particular are often not picked up by the radar systems of large container ships and cruise liners, and this can make things quite dangerous.  It is incumbent upon all sailors to keep a check on the sea conditions around them in order to stay safe from other vessels.

Thankfully, even the fastest ships do not usually move at more than about 25 knots, which means that if you have a radar that covers 50 nautical miles, you will have roughly 30 minutes from the moment when you first make contact with another vessel until the time when you would meet, which should give you plenty of time to react and plan your navigation accordingly.

If you package together a high-speed antenna with a large format radar screen, you will be able to get a very detailed picture of what events are going on around you.  A modern radar array like the Furuno 1932MK2 will allow you to enjoy a 10" screen that provides plenty of scope to see what is happening.  The whole Furuno range are well known for the high quality of their equipment, and the regularly updated range boasts the latest technology, and is always at the cutting edge of marine radar systems.

One of the great things about modern marine radar systems like the Furuno is that they plot the relative position of other ships over time.  Rather than being just abstract dots on the screen which convey little information, other vessels appear as a track through the area.  Their movements are shown in clear detail, allowing you to easily gauge which other vessels pose a threat to you and take appropriate action.

When you are at sea and out of sight of land, your safety should always be your priority, so rather than leaving your own safety up to the actions of other people, you can keep yourself safest by having a marine radar system that works, and make your course corrections based on the up to date information that it provides.

By learning to read the information provided by your marine radar system, you will be able to make informed decisions about how to navigate, in order to best avoid trouble at sea.  Knowing what is approaching you and what is happening beyond your visual range will allow you to be certain that you are safe, and also able to react in a timely manner to anything that happens, whether it is a weather system, a super tanker, or even a wave..

It is important to know what other vessels are doing, but it is also important to keep tabs on what you are doing.  By tracking your own progress across the ocean, and taking the time to do the same for other boats by using a marine radar plotter like the Furuno 1932MK2, which has a 10 inch screen, you will be able to protect your boat, crew and passengers in the most effective way possible. 
Instructions

Things You'll Need:

Operating manual for your radar unit

Step 1

Set the range rings of the radar. Usually, this is accomplished with a switch or dial on the unit; most units can be adjusted to cover a range from 1/4 mile to over 48 miles. The most useful settings are 4 to 6 miles for a small boat on open water and 1 to 2 miles (or less) on lakes or rivers. Shorter ranges give a more immediate picture of the situation surrounding a boat in close quarters.

Step 2

Use the Variable Ring Marker, or VRM, to determine the distance to a particular target, such as the mouth of a river, a sea buoy marking a channel entrance or another vessel. The VRM is like a standard range ring, but can be adjusted by a control (usually a knob) on the radar display so that it can be "moved" to a target. The VRM distance display will show the exact distance to the target.

Step 3

Use the Electronic Bearing Line (EBL) to determine the exact relative bearing to a target. The EBL, like the VRM, is adjusted by a knob on the display, allowing the EBL to be moved to a target and to display the exact bearing relative to the direction of your boat's travel.

Step 4

Use the EBL and VRM together to determine if a target is moving toward you in a "crossing situation" that will require your action. Put the VRM and EBL on the target; they will intersect at the target's location. If the range decreases but the relative bearing does not, the target is a vessel and a crossing situation is developing. If the range decreases and the relative bearing changes, a crossing situation is unlikely, but the prudent mariner will take care to maintain watch for the unexpected.

Step 5

Always trust your eyes before you trust the radar. Maritime law, the Rules of the Road for Inland Navigation and the Regulations for the Prevention of Collision at Sea, take no notice of radar except as a navigational aid, and then insist that decisions based on radar observations be confirmed visually. The ultimate responsibility for safe navigation rests with the master, not the radar, and numerous court cases cited in the Rules affirm this fact.

The Coast Guard's weather broadcast on your boat's radio may warn you of impending "heavy weather," but tracking an approaching storm's progress on your boat's radar allows you to take substantial action early enough to avoid the property damage and loss of life that a storm on the water can bring. Even after you make port, if you remain aboard your vessel (assuming your boat has a weather-tight cabin), you can still track the storm with your radar unit; should the storm blow itself out, either abandon your activities or enjoy the calm seas that follow.

Difficulty: Moderate

Instructions

Things You'll Need:

Stopwatch Calculator

Step 1

Change your radar's range to 48 nautical miles when you become aware of the storm visually or by radio broadcast. At 48 miles, your radar won't pick up anything below 1,200 feet in height, so you'll see the largest part of the storm. Once you've ascertained the general size of the storm, reduce the range of your radar until the edge of the storm is visible.

Step 2

Turn the "VRM" knob on your radar to set your radar's Variable Ring Marker on the edge of the storm. This will display a single ring that can be moved with the knob. Its range will be displayed in one corner of the screen. Note the range to the storm's edge.

Step 3

Start your stopwatch for a three-minute count and note the range of the variable ring marker. If the storm enters the area in less than three minutes, stop your stopwatch and decrease the range of the VRM until the line is again touching the edge of the storm. Note the new range of the variable ring marker.

Step 4

Subtract the new range from the original range to the storm; this is how far the storm traveled in the time recorded by your stopwatch. For example, 12.5 miles (original range) - 10.2 miles (new range) = 2.3 miles. If it took the storm 2.5 minutes to go 2.3 miles, then divide the distance traveled by the time and multiply the result by 60. For example, 2.3 (the distance traveled) / 2.5 (the time it took for the storm to travel the distance) = 0.92. Multiply the result by 60 to determine the relative speed (the storm's speed relative to your boat) of the storm. In this example, 0.92 x 60 = 55.2 miles per hour.

Step 5

Note the storm's apparent direction of movement, relative to your course, on your radar by turning the knob marked "EBL," or electronic bearing line, until the EBL parallels the course of the storm. Note the bearing indicated (also in the corner of the screen, similar to the VRM). This is the relative bearing of the storm.

Step 6

Subtract the relative bearing of the storm (the EBL bearing) from your course with your calculator. If your course is 245 degrees, and the electronic bearing line shows the course of the storm as paralleling the EBL set at 290 degrees, then 245 - 290 = -45. Add this to your course to determine the true course of the storm. In this example, 245 + (-45) = 200 degrees.

Read more: How to Use Marine Radar for Storm Tracking | eHow.com http://www.ehow.com/how_5872005_use-marine-radar-storm-tracking.html#ixzz0w1bV0k3G