COLLISION AVOIDANCE
There is a battery of technology available to stand watch and alert you to potential dangers
Lulled by the rhythm of the ocean swell and the long hours of scanning a horizon that is no more than a few miles distant, it is every sailor’s fear to strike some halfseen object in the water. Fortunately, a battery of technology is available to stand watch when you rest. Computing power that was inconceivable on a yacht just a few short years ago is now fairly commonplace.
There’s Automatic Identification System (AIS) of course, a relatively low bandwidth technology that should be in every offshore sailor’s toolkit. It is simple to set up a perimeter alarm to warn you when another vessel with AIS comes near.
New radar units that exploit greater processing power can crunch radar signals faster and more accurately, giving a far more detailed visual display for users. They can track targets using a Mini automatic radar plotting aid (MARPA) – another line of defence for weary mariners.
The next step up is a dedicated collision warning device like the new Oscar. This masthead-mounted unit uses thermal and optical cameras to scan the sea ahead. It can spot objects from 1m² and sound an alarm, but it cannot see past the surface.
A forward-looking sonar could in theory spot a submerged container or a whale lounging up ahead, although their main function is scanning the seabed for rocks and shallows.
Although the technology has existed for some time, solid-state radar has really emerged in the past five years in the leisure boating sector. At first it was hailed as a way to reduce the weight of the radar array up on the mast and to cut power consumption – both key benefits for sailors. But recent developments have enabled new Doppler functionality to appear, which makes them even more useful for collision avoidance.
The Doppler effect says that an object moving towards you will compress the reflected radar signal, while those moving away will do the opposite
– just as a car driving towards you makes a higher pitched noise than it does once it passes you. This characteristic means that the radar unit can identify much more quickly whether an object is approaching the boat. Then it can warn you accordingly, perhaps plotting the approaching object in red and sounding an alarm.
B&G’S Halo 20+ and 24, Garmin’s Fantom and Raymarine’s Quantum 2 radar units all have Doppler technology built in. ■ Halo20+ costs £2,480, Halo24 is £2,853 www.bandg.com
■ Quantum 2 costs from £1,699 www.raymarine.co.uk ■ Fantom is from £2,180 www.garmin.com