Modifications - CARD System

Added to the boatís inventory on 26/5/02, this Collision Avoidance Radar Detection System is being evaluated in terms of its effectiveness and where on the boat it should be sited. Sensors within the antenna detect being hit by a ships radar beam. LEDs are illuminated according to which sensors registered a contact. In principle, the greater the number of LEDs illuminated the closer the relative position of the other vessel.

The screen shot below shows a practical illustration of a ship having been detected passing astern. In addition to the visible alarm, an audio warning may also be issued Ė the operator has the choice of High, Low or No audible alarm.

Initial trials with the antenna mounted low on the coach roof resulted in detection of ships after they had already entered visible range.

Further trials with the antenna mounted approximately 8ft above sea level produced mixed results. For example; two ships within the TSS (Traffic Separation Scheme) off Anglesey did not activate the CARD system (note that commercial ships are not legally required to operate their radar equipment at all times), alarm continuously sounded though no shipping visible in the vicinity Ė maybe rain confuses the sensors, and even at the new height ships still detectable by eye before their radar starts triggering the CARDís sensors. Also noticed when the Sea Cat was leaving Holyhead, a few miles distant to Balstara at the time, that itís radar caused only a weak signal on the CARDís display unit when itís bow was towards the CARDís antenna, but that the signal became much stronger when the Sea cat turned 90 degrees to take on a Ďbeam oní attitude.


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