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post #9 of Old 11-27-2012
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Re: AIS very handy yesterday...foggy on SF Bay

In New Zealand they have started to use AIS as remote navigational markers in places they can't put a buoy...
The transmitter is 4 miles away from the place it appears to be on AIS receivers.


Using our core AIS technology Vesper Marine has deployed a Virtual Aid to Navigation at the entrance to Doubtful Sound, a fjord in New Zealand’s South Island.

The 80 cruise ships entering and exiting the beautiful Doubtful Sound each summer need to be able to identify a very dangerous underwater obstacle known as Tarapunga Rock. This rock lies just below the surface, close to the entrance to Doubtful Sound. In the past an isolated danger buoy had been moored at the rock’s location; however as the swell could exceed 7 metres at times the buoy broke up and had to be removed.

Vesper Marine provided a Virtual Aid to Navigation system that enables proactive electronic visibility of Tarapunga Rock for all vessels using AIS. A Virtual Aid to Navigation (VAtoN) is created by sending a signal from one location (point A) that marks a remote point (point B). This virtual mark, point B, is displayed as a navigational hazard on a ship’s chart plotter, AIS display or other receiving equipment when within range of the transmitting equipment installed at point A. A ship’s onboard equipment is also able to alert crews if they are on a collision course with the marked navigational hazard.

The VAtoN system was installed at an existing navigation light stationed on nearby Secretary Island. The location of this light is so remote it can only be accessed by helicopter and has to be solar powered.

Despite the remoteness and rugged landscape the installation is proving to be successful and it is achieving good coverage. Ships entering Doubtful Sound can now identify Tarapunga Rock from as far out to sea as 10 nautical miles (nm).

This has been a fantastic project to work on and the ease and relative low cost of deployment gives us confidence that many more navigational hazards can be marked in this way improving environmental and passenger safety for any coastline.


Sea Life
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