Automatic Identification System (AIS) is one of the newer navigation technologies we have installed for our trip. It enables nearby vessel location and speed data to be shared automatically. All commercial vessels and many fishing boats have AIS, all yachts in the ARC have it too.

Each vessel broadcasts its location, speed, course and identity and receives this information for other AIS equipped vessels nearby. Each vessel’s system calculates the relative course and speed of nearby vessels and alerts possible collisions through an alarm. Vessels are plotted on a screen similar to a radar display, which can be linked to a chart plotter so that vessels are shown on the electronic chart.

AIS uses VHF radio for its communications. In practice VHF range is limited to line of sight, about 30 miles, ideal for local collision prevention.

Other most useful benefits of the system:

Man overboard alarm & location – each of us have an AIS beacon on our lifejackets which automatically activates if we fall in the water. This broadcasts an alarm with details of locations to all vessels in the vicinity, including our own of course! It is by far our best chance of recovery!

Remote tracking of vessels.

http://www.marinetraffic.com is a website which publishes the location of vessels within range of a network of AIS receivers operated by volunteers around the world. This allows search and location of vessels of interest – provided they are within range of one of the automatic shore stations operated by volunteers. Clearly this is excellent to locate vessels near to shore, but cannot help when they are far out to sea!

You can track our progress in real time by searching for Alize in the vessel search. Our boat is the first one that comes up in the search: a sailing vessel registered in UK.

Other benefits for navigation:

• The information on each vessel includes its call sign so that a direct radio call can be made to an individual vessel.
• Navigation marks also transmit their location using AIS and show up on the display – very useful as a check against the electronic chart.

 Mike, Tim & Mike (just off Benidorm!)