Please select your home edition
Lennon Thermalite 728x90 2

Global Solo Challenge: What is an AIS? An essential instrument for safety on a sailing boat

by Global Solo Challenge 4 Sep 2021 03:10 PDT
Chart table © Global Solo Challenge

The acronym AIS stands for Automatic Identification System. It is used by ships, pleasure boats and traffic control stations. The system allows information on the position of nearby ships and shore stations to be exchanged electronically.

The tool supplements the information provided by the RADAR which still remains the main anti-collision tool for commercial ships today. The radar watch with automatic MARPA mapping remains mandatory for large vessels.

However, for years AIS has become mandatory for ships over 300 tons. It is also rapidly spreading in pleasure craft, particularly among fishing boats and racing boats. Initially, receivers became popular, relatively cheap compared to instruments capable of receiving and transmitting. However, more and more offshore regattas have made it mandatory to have a transceiver. This is starting from Category 2 regattas according to the World Sailing classification.

Information transmitted

The AIS transmits and receives on dedicated VHF digital bands, on channels not selectable by the on-board radio. Each vessel or shore station equipped with a transmitter periodically sends accurate information about its position, speed and course. It also sends other useful data such as the type, size and name of the vessel, the number of MMSIs. For large ships, the destination, estimated time of arrival, type of cargo, etc. are also indicated.

This allows any boat equipped with a receiver to have all the information necessary to avoid collisions and much more. With the radar it is possible to identify another boat in situations of bad visibility. With AIS it is also possible to instantly determine its speed and course and, if there is a risk of collision. Consequently, who has the right of way according to the type of boat. Moreover, knowing its name, it will be possible to call via VHF or DSC digital channel using the MMSI number.

AIS class A, B and C

There are instruments of various classes based on functionality and scope. All commercial ships over 300 tonnes and all passenger ships are equipped with AIS of class A. These instruments transmit with very high frequency through a dedicated antenna and receive data from all types of AIS. These units have a system of prioritization of the transmission of navigation data. This ensures that if there are many ships in the same area, none of the signals overlap with others.

The system architecture manages up to 4500 stations in the same area. Class A must also be equipped with a dedicated display and a calculator that analyses the risk of collision with any other signal received.

Class B

On the smaller ships, on many fishing boats or on pleasure boats there are Class B instruments. These also transmit and receive but are less powerful than Class A. They are also not equipped with a prioritisation system for the transmission of navigation data. They can have a dedicated screen or they can provide information to be displayed on the chart plotter or laptop. The installation of class B units is very often voluntary but, as already specified, it has become mandatory for Category 2, 1 or zero regattas. For example the Rolex Fastnet, a Route du Rhum or the Vendee Globe respectively.

Continue reading the full article here...

Related Articles

Global Solo Challenge reaches 40 entries
An incredible milestone for the event First, we received two new entries bringing the total to 40. It is such an incredible milestone for the event. We never imagined the first edition of the Global Solo Challenge could receive so much interest. Posted on 12 Jan
How to deal with seasickness and manage it safely
Seasickness poses major problems when sailing and can become a big risk factor Seasickness is caused by the interaction between the organs of balance, the visual and tactile systems and the brain. While being thrown around a boat, our brain cannot reconcile the messages it receives. Posted on 23 Dec 2021
Polyphasic sleep: sleep management solo and crewed
The fundamental principles of polyphasic sleep management Polyphasic sleep management when sailing single-handed is one of those aspects that terrorises each and every sailor who has not yet sailed by themselves. It is not a simple subject to deal with and requires plenty of practice. Posted on 20 Dec 2021
Preparing for a solo circumnavigation
Preparation is key to success, but the list seems never-ending Preparing for a solo circumnavigation by the three great capes is an enormous challenge. So much so that getting to the start line is often just as hard as the navigation that will follow. Posted on 17 Dec 2021
What brings people to like single-handed sailing?
Global Solo Challenge skippers asked for their reasons Sailing single-handed is one of those things that bring unparalleled sense of satisfaction and achievement. I remember my first solo Atlantic crossing, I was mesmerised, I loved it. Posted on 14 Dec 2021
What lessons can you learn from sailing?
Global Solo Challenge skippers interviewed Sailing can be considered a sport, but many prefer to refer to it as a discipline. Sailing, especially single-handed and long-distance, requires an incredible number and combination of skills. Posted on 4 Dec 2021
The biggest solo circumnavigation challenges
What are the recurring thoughts of many Global Solo Challenge skippers Preparing boat and skipper for a non-stop single-handed circumnavigation by the three great capes is no easy task. Many are the challenges during preparation, financial, practical, as well as during the navigation itself. Posted on 29 Nov 2021
Why did they sign up for Global Solo Challenge?
We asked our skippers what brought them to the race We asked our skippers what brought them to sign up for the Global Solo Challenge and below we picked a selection of answers which gives a feel of how the event is perceived by entrants. Posted on 27 Nov 2021
Racing ropes: making the right choice
The world of ropes is much more full of variations than we might think The ropes for a sailboat seem at first glance all the same except for the colour. Nothing could be that far from reality. Some ropes have truly remarkable technical properties. Others are not quite as noble and we need to understand the differences. Posted on 6 Nov 2021
Weather information on board a sailboat
Every skipper must have a clear idea of the current weather situation and the expected forecast Every skipper, whether on a sailing or motor boat, must always have a clear idea of the current weather situation and the expected forecast. Posted on 30 Oct 2021
Hella Dual Colour Floodlights - 728 x 90px - 004 gif BottomCoast Guard Foundation FOOTER 1Rooster 2020 - Impact BA - FOOTER