Ciel et Marine offers two complementary devices. The first, the Mer-Veille, is a radar signal alarm. This device reacts when it detects a radar signal. It can then be used to intensify on-board surveillance (?387 incl. VAT). The second has the same alarm function, but this time on AIS signals.
The AIS (Automatic Identification System) is a worldwide system organized by the IMO (International Maritime Organization) which provides information on the navigational characteristics of vessels by transmitting radio messages in the VHF band. This information, provided on board a pleasure boat by an AIS receiver or transponder, indicates the presence, position and course of nearby vessels transmitting an AIS signal. This makes it possible to calculate the potential risk of collision.
However, most AIS receivers are black boxes, which need to be connected to a display (multifunction device or computer) to trigger an alarm. These screens consume a lot of energy if they have to be switched on continuously. The CA21 avoids this problem.
Very low power consumption
In standby, the CA21 consumes less than 10 mA! It's an information analysis unit. It automatically processes messages from the AIS. This information is fed into the CA21's alarm calculator to determine the CPA (Closest Point of Approach) and TCPA (Time to CPA), and decide whether to trigger an alarm based on one of four user-defined alarm levels. The CA21's extremely low power consumption means that it can be used as a permanent, display-independent collision-avoidance monitor, which can of course still be used, particularly in the event of an alarm.
4 alarm levels
The CA21 continuously analyzes the signals from the AIS receiver combined with the onboard GPS position. Each AIS message received is subject to an anti-collision check, with calculation of CPA and TCPA. An audible and visual alarm is triggered if the alarm level is reached:
- Level 1: All ships, each position message received triggers the alarm.
- Level 2: CPA < 6 miles and TCPA < 30 min.
- Level 3: CPA < 4 miles and TCPA < 20 min.
- Level 4: CPA < 2 miles and TCPA < 15 min.
The audible alarm is triggered by a buzzer inside the box. The duration of the buzzer at each alarm is indexed to the importance of the hazard, providing intuitive auditory information on the imminence of the danger and its evolution.
The visual alarm is given by the LEDS (indicator lights): the bearing (position relative to NORTH) is given by the lighting up of 1 or 2 LEDS, i.e. 8 possibilities.
The CA21 connects to a 12 V power supply and to the NMEA _0183 AIS and GPS network. Entirely assembled in France, it is available at ?190 (price incl. VAT 2024).
