The Maritime and Coastguard Agency (MCA) has updated its guidance on the use of a radar reflector on boats less than 15m/49.2ft and under 150 gross tonnage. 

Marine Guidance Notice (MGN) 349 states that a radar reflector or radar target enhancer should be permanently installed, and offer the largest radar cross section (RCS) as practical for the vessel.

Commercial ships use radar equipment that operates in the ‘X’ band (9GHz) and the ‘S’ band (3GHz).

A radar reflector on a recreational boat should have a RCS of at least 7.5m² at X-Band and 0.5m² at S-band when mounted at a minimum height of four metres above sea level.

The RCS should be maintained over a total angle of at least 280° of azimuth and not below this level over any angles greater than 10° (a null).

There should not be a distance of less than 20° between nulls.

For power driven vessels and sailing vessels designed to operate with little heel, such as a catamaran or trimaran, this performance should be maintained through angles of (athwartships) heel 10° either side of vertical.

For other vessels, the radar reflector should maintain this performance over 20° either side of vertical. Any radar reflector…