A radar reflector is a device which is attached to a boat to make it more visible on radar. Radar reflectors consist of several pieces of metal which intersect with each other to create a geometric shape which will strongly reflect radar. There are a number of different styles and designs available, and several boating safety organizations have tested a range of radar reflectors to see which models and designs seem to work best, obtaining varying results which seem to indicate that even with a radar reflector, a boat can sometimes be hard to spot on radar.
Boats made from wood or fiberglass tend to show up poorly on radar, in contrast with metal boats, which provide a nicely reflective target. The lower a craft is to the water, the less it will show up on radar, and the smaller a craft is, the less visible it will be. All of these problems can compound to make a small boat virtually invisible to passing ship traffic, which can be very dangerous. A radar reflector is designed to address this problem.
A radar reflector reduces navigational hazards by providing a surface for radar to bounce from, generating a return which can clearly be read on radar screens. This will allow larger ships to clearly see small boats in front of them, which can help captains reduce the risk of collision. Using a radar reflector also makes a craft like a lifeboat more visible on radar, allowing it to be found more quickly.
The rules of the sea dictate that smaller craft need to yield to larger craft, because small boats are easier to maneuver. However, it is also important for captains of boats of all sizes to take care to avoid hitting other craft, which can include sounding horns to alert small boats to an oncoming large ship, changing course slightly to avoid hitting another boat, and being especially alert to disabled boats which cannot yield. Large ships use radar to detect passing and oncoming ship traffic, and boats which are invisible to radar may be not be spotted, which means that a collision could occur, and on a huge ship, people might not even be aware that a collision had happened.
Many marine supply stores and catalogs sell radar reflectors, which usually come with the necessary mounting equipment. It is important to mount the reflector high on the mast so that it will be well above the water level, with heights of at least 15 feet (4.6 meters) above sea level being strongly recommended to ensure that a radar reflector will be clearly visible. Boaters who do not feel comfortable performing the installation on their own can hire someone to do it, and some boating safety organizations may perform free installations on days when they hold safety workshops and informational sessions.