Types of AIS - Understanding Class A & Class B AIS Systems for Boats

Auto Identification Systems, also abbreviated as AIS have made the life of mariners a lot simpler, better, and safer. How? They do it by helping with not only exchange navigational information between different AIS-equipped terminals but also by keeping you seen and safe wherever you sail!

With the advent of technology, now you can avail different types of AIS systems for small boats, yachts, and other vessels. From the most-hyped Raymarine AIS, Garmin AIS, and Humminbird AIS to Vesper Smart AIS, Digital Yacht AIS, and FURUNO AIS - the choices are many and all come with different sets of features accommodate your needs.

Knowing marine technology is improving every day and becoming affordable than ever, you can actually get the best AIS for yachts, or small boats from trusted brands to ensure your safety and comfort onboard. In this post, we’ll talk about the types of AIS devices and the concept of AIS on the Internet. Let’s get started:

Types of AIS devices:

There are generally three types of AIS equipment for shipboard fitting, these are - Class A, Class B, and receive only.

Class A AIS Systems

Class A category of AIS is meant for vessels with a mandatory fit. They transmit more data, at a higher speed, and at a higher power compared to Class B.

Most information in an AIS transmission is received from other devices on the vessel, for example, Course Over the Ground (COG) and Speed Over the Ground (SOG) from GPS. However, there are some data that need a manual entry like vessel status that can be “underway”, “at anchor”, “alongside” or more. In the same manner, the next port of call and the numbers of passengers.

Full-function transceivers are needed for ships above 300 gross tons traveling internationally, as well as for passenger ships. Different classes of commercial vessels are recently added to these requirements a few years ago. Class A AIS systems incorporate both transmitters and receiver. They automatically transmit every 2-10 seconds while the ship is underway, and every 3 min while the ship is anchored. Transmitting at 20 watts, Class A AIS use ample electrical power. These units are additionally costly.

Class B AIS Systems

Class B AIS is meant for voluntary fit watercrafts and vessels. It is mainly “fit and forget” and doesn’t need manual updating. Vessel details are entered when it’s installed. Afterward, it sends vessel details such as name, callsign (MMSI), location, COG, SOG, etc.

Both the categories (Class A and Class B) of AIS receive data from different vessels. This data is then used for the placement of icons on the plotter screen. These AIS, in turn, can be examined to confirm all the data provided.

Class B AIS units offer a slightly reduced set of features at a pretty lower cost. These are ideal for recreational vessels and vessels that don’t need to carry Class A AIS. Class B category of AIS has been approved for use throughout the U.S a decade ago. It is almost indistinguishable to Class A, except that Class B AIS offers less frequent reporting rate in comparison to Class A. it offers the reporting rate of every 30 seconds while traveling at more than 2 knots, while Class A offers every 10 seconds). And it doesn’t transmit vessel destination, IMO number, ETA, draft, or the rate of turn either. Saying positively, Class B AIS uses less electrical energy as compared to Class A.

You can easily choose between Class A and Class B AIS from popular brands like Garmin AIS, FURUNO AIS, Humminbird AIS, Raymarine AIS, and more.

Receive-Only AIS Systems

The third and the last option of AIS for small boats is receive-only. It means, such a unit will only receive AIS transmissions from other vessels and show them on the plotter’s screen. The outdated equipment for the small boats used to be received-only. A few years later, the Class B category came into the market and is now a preferred choice over this one. With receive-only AIS, you are only able to view what other vessels are doing. The drawback is, they won’t know you exist! You wouldn’t want your small boat to be ignored by a large vessel and lead to a mishap just because they couldn’t see you. Large vessels have become more used to seeing small boats on AIS. given that, vessels transmitting AIS are more likely to be noticed as compared to those that aren’t.

Models such as Raymarine AIS350 is one of the receive-only units. It doesn’t work like two-way transceivers do, and allow you to recognize what ships are in the proximity while you are off the AIS grid. Imagine a receive-only unit that works more like a radar than a radar unit having a radar reflector. These receivers, having only the 2-channel VHF receiver & decoding software, don’t belong to Class B category. Why? Because they aren’t active transmitters on the AIS system.

Recently, AIS Man Overboard marine devices have gained popularity. One out of few manufacturers integrates such capability into its lifejackets. These have a plus point over the traditional satellite-based units (like EPIRBs) given they show up on chart plotters on surrounding vessels while the EPIRBs only alert the shore side SAR authorities.

AIS on the Internet

You will find multiple websites and apps on the web that enable you to look over AIS. These sites work by fetching the data from different receiving points surrounding the coast and summing up it to provide an overall clear picture. The coverage persists to improve; however, there are gaps. While tracking a vessel going out of coverage and coming back infrequently, the application will show a straight line between the two.

You will also find some applications transmitting AIS from a smartphone or a tablet. It is vital to remember they aren’t transmitting on VHF, but only sending data directly to the Internet over the phone data system. That been said, the information will not be displayed on a regular VHF AIS receiver.

Conclusion

So now you know what are the three main types of AIS systems that you can consider. No matter you have a small recreational boat or a big yacht, you can choose from the best AIS for yachts, AIS systems for small boats, check AIS transponder price, and everything online! There are many e-stores offering you a wide collection of AIS for different vessels. So don’t hold back. Choose one for your vessel today to let yourself free and enjoy the marine view while the AIS takes care of your course.