Collision Regulations:  (Radar & Passive radar reflectors)

Radar is an electronic system used for detecting the presence, position, or movement of objects. Mounted high on a vessel, radar antennas rotate and can be of the open array, such as the two wing-like ones shown at left above, or they can be enclosed within a dome, (like the upper most one).  As the antenna rotates, it sends out short radio waves that can be reflected back by objects all around, such as other boats, buoys, land, and even heavy rain. 

A "radar reflection" from these objects appears on the senders radar display screen.  However, non-metallic objects do not reflect radar waves very well.  Therefore, small non-metallic vessels, even close & directly ahead, may not show-up on radar screens and are therefore at a greater risk of collision at night, or in fog.

To be better seen by vessels (with radar), especially during periods of restricted visibility, the Collision Regulations require all pleasure craft 20 metres in length or less, or those vessels which are constructed mostly of non-metallic materials, (such as wood, or fibreglass), to be fitted with a passive radar reflector.  Passive (means not powered) radar-reflectors are lightweight thin metallic devices, shaped to reflect the microwave pulses back to vessels fitted with radar.  For the best effect, the device should be mounted 4 metres above the water or more, if practicable.  (Note the passive radar reflectors shown in the pictures top right and at left).

Compliance with the above rule is not mandatory if;

• the small size of your pleasure craft makes such an installation impracticable and,
  
• you only operate your pleasure craft during the day, in good seeing conditions where such a device is not essential for safety, or,
  
• you operate your small craft in an area away from radar navigation.
  

Radar screen showing the image of 3 vessels nearby.  Top of the image is looking ahead.

Some passive radar-reflectors fold-up for easy storage.  They can be unfolded and hoisted to a high point on your pleasure craft when required.  Sailboats often attach one (permanently), high on a mast shroud (one of the ropes or wires supporting the mast), shown top right above.

Even with a radar reflector, be sure to use sound signals when caught in fog!
Go dead slow and keep a sharp lookout!