We are looking at the latest in AIS equipment. AIS transponders, AIS receivers, & AIS engines, including class B now available in the US.

Since the original story on AIS we wrote over a year and a half ago there are many changes to be mentioned. The basic system has not changed. What has is the increasing number of AIS receivers, transponders, made by manufacturers plus the increasing number of software applications available.

The second most important development is the approval of AIS class B transponders in the US. United States Coast Guard on Class B approval October 2008

AIS transponders have been a legal requirement on ships over 300GT for a while. Yachts and boats with AIS receivers can see those vessels, on a radar type plot shown on their chartplotter. All they require is an AIS receiver, sometimes known as an AIS engine, connected to a VHF aerial and to the GPS plotter.

There are two types of AIS transponders, class A & class B. Class A AIS transponders are for Commercial shipping, and transmits, via 2 channels and typically are fully integrated into the ships navigation systems. Class B transponders are for smaller vessels. Class B signals are sent every 30 seconds, compared with as frequent as 2 seconds for Class A.

AIS signals are different from radar and can be used as a supplement to radar or an alternative if you do not have radar. AIS signals only show the shipping traffic and not weather and can also see around corners.

Now you can transpond or transmit as well as receive, there is a debate about which unit you should go for. Receive only allows you to monitor all AIS traffic, while the transponder allows you to send your own signal.

Manufacturers of AIS equipment

Full AIS Class B receivers & transponders

Not included here are the electronic manufacturers own AIS devices including the AIS500 from Raymarine due out next month.



Nauticast B AIS
Class B Automatic Identification System FCC Approved

The Nauticast is an example of a receive and transpond AIS unit which has received FCC approval for the US.

The ACR Nauticast-B Class B AIS Transponder kit includes the following items: Class B AIS transponder unit, Product manual, GPS antenna with 20 foot cable GPS mount VHF ACR A-3200 AIS antenna with mount and 15 foot cable Power/ECS/PC interface cable (4 foot).

ACR Nauticast features:

Transmit and receive AIS

Plug and Play

GPS Receiver

Water Resistant

Remote SRM Switch

Small in Size

Cost around $799

The Nauticast B AIS RS232 and RS422 NMEA electrical interface communicate data directly through the users chart plotter or laptop. All in all Nauticast B is one of the best AIS class B units on the market.

 

In order to comply with FCC regulations, these units must be pre-programmed with your vessels information. See more information below.

Full manufacturers details

 

RadarPlus AIS-BX- Class B AIS
Full Class B AIS Transponder including Dual AIS receivers, Class B AIS transmitter, internal 16 Channel GPS, power/serial interface cable

AIS-BX Class B AIS is Approved in the U.S

This unit is sold by many instrument retailers maybe under a different name.

AIS-BX features:
Transmit and receive
The AIS-BX includes an integral 16 channel GPS. (Antenna sold separately.)
The AIS-BX can interface with any NMEA compatible GPS plotter or suitably configured PC.
Water Resistance; IP65 rated aluminum case ensures that the AIS-BX is able to operate in harsh environments.
RS232 38.4K baud bi-directional
RS422 NMEA 38.4K baud bi-directional
VHF Antenna Connector: BNC female, GPS Antenna Connector: TNC female
Cost around US$800

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Programming required for Class B AIS

(not required for the receive only units)

You will need to have the init programmed by an approved merchant and have an MMSI number.

MMSI Number

 

If you elect to get a class B transponder you will need to program the unit with certain information including your MMSI number. If you have not already got one You will need to apply for a MMSI number the same as for DSC.

 

Register here for MMSI numbers

 

Some of the details you will need to get programmed into the transponder include; Ship's name (20 characters maximum), Vessel's radio call sign (7 characters maximum), MMSI number, Vessel type  and certain vessel's dimensions. This information is sent in your AIS signal which tells the receiver who you are COG, SOG, call sign etc.

In addition to your MMSI number, you will also need to provide the following information that will be programmed into your Class B Transponder:

• Ships name (20 characters maximum)

• Vessels radio call sign (7 characters maximum)

• MMSI number

• Vessel type

• The vessels dimensions as follows (to the nearest meter): distance from bow to GPS antenna location, distance from the GPS antenna to the stern, distance from the port side to the GPS antenna, distance from the GPS antenna to the starboard side

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More AIS equipment (non Class B)


AIS repeater/display

AIS WatchMate

Sail magazine recognized 15 sailing products for its 2009 Pittman Innovation Awards. One of Peter Nielsen’s Cruising Gear awards went to Vesper Marines AIS WatchMate.

AIS WatchMate is a repeater connected to an AIS receiver and is a stand alone display showing AIS data from all shipping in the area.

It can serve as a backup to seeing the AIS target on your chartplotter.

This device would work well if you do not want to clutter up your chart screen with loads of AIS data and keep it solely for navigation, while looking at the WatchMate to see AIS traffic.

AIS receivers only (non Class B)

ICOM

ICOM make some very good VHF and navigation units. So it no surprise they are entering the AIS field as the same VHF airwaves are used. The MXA-500 is a AIS Duel Channel receiver, which is fine with many boaters. Being able to plot AIS targets on your chartplotter aids your navigation.

By having an AIS transponder allows you to send your target, but many ships in a shipping channel will ignore it or filter it out, putting the burden on you to keep clear.

The MXA-5000 dual channel AIS receiver allows boat owners to receive AIS information (both Class A and Class B AIS signals) on two channels simultaneously and outputs this real-time information on a computer, radar or a chart plotter, thus aiding navigation and collision avoidance.

The MXA-500 was first shown at the London Boat Show 2009.

Smart Radio SR161, AIS Receiver is a well respected and cheap option if you are looking for an AIS receiver, but not interested in transponding or broadcasting.

Class B AIS units are available in the US now but they run closer to $800 and may not be worth it. The SR161 costs closer to $190.

Sending an AIS signal lets other vessels know where you are but many believe its better to know the other vessels in your area and not send a signal yourself. Pilots in heavy shipping areas will be filtering out signals to reduce their screen down the commercial vessels only.

The SR161 is a single channel receiver, flipping between channels and hence will not report as fast as a dual channel receiver. This can be an issue if you are tracking fast craft.

Useful resources

marinetraffic.com

This site and others below let your monitor shipping traffic in commercial ports.

Real time plots of traffic can be seen along with their name registry etc. See the box to the left. Both these images are of traffic in Baltimore and the Chesapeake Bay.

This means that even though you may not have AIS on your boat, if you have an internet connection you could see what is happening around you.

vessel tracker