Although radar reflectors are required for boats under 20m (65’7”) and boats that are built of mostly non-metallic materials, there are some exceptions where a radar reflector is not required.
Small boats are generally not identifiable by radar by large ships because they are mainly constructed of non-metallic materials and because their superstructure is small. In bad weather, they are often not visible because of mist. When they are in the hollow of a blade and even in good visibility, the fact that they are very low on the horizon makes them difficult to see from the bridge of a large ship. At night, their navigation lights may well go unnoticed because of shore lights in the background. It is important that small boats use radar reflectors to signal their presence to other vessels in the area, especially in poor visibility.
A radar reflector can enhance your safety on the water, but only if it’s big enough and strategically placed on your boat. Reflectors help larger vessels spot smaller boats on their radar screens, which is often the only way to see you. When buying a reflector, there is no substitute for size — so buy the biggest one that is practical for your boat. Both the Collision Regulations and the Rules of the Road for the Great Lakes require a vessel that is less than 20 metres in length or is primarily constructed of non-metallic materials to carry a passive radar reflector that meets the required standards.
A radar reflector should be located above all superstructures. Height is very important, so also keep this in mind that the higher you can position the radar reflector the better it is. Reflectors should be placed higher than all superstructures and at least 4 m (13’1”) above the water if practical. There are many kinds of reflectors of varying quality on the market, so shop carefully before you buy.
A radar reflector can enhance your safety on the water, but only if it is big enough and strategically placed on your boat. When buying a reflector, there is no substitute for size, so buy the biggest one that is practicable for your boat. This being said, when navigating in busy seaways, at night or far from land, a radar reflector is a rather cheap device to have and one that is easy to rig up. It should be installed in an area where it is a minimum 4m (13.1 ft) above the waterline and higher than all the surrounding superstructures to ensure that you’ll be seen on the radar screen of large ships and fishing boats. Height is very important.