YAAC does not handle AIS data directly. You will need to get an NMEA-0183 feed that provides the AIS sentences (such as the AIS-Catcher in TCP server mode via the marineports plugin's port driver). However, the DireWolf software TNC is also capable of demodulating AIS packets (assuming a suitable receiver and sound card are used) and converting them to experimental data APRS packets encapsulating NMEA-0183-formatted AIS frames. Connecting YAAC to such a DireWolf instance using AGWPE or KISS-over-TCP port types allows the AIS decoder plugin to parse the AIS frames and render the resulting ship information on the YAAC displays.
Per the DireWolf documentation, the direwolf executable (of release 1.6 or later) should be launched with the following command-line options:
-B AIS -r 48000
The normal configuration file options should be used to specify the sound card, which must
support at least a 44100 Hz sample rate (preferably 48000 Hz); note the -r
option above specifies the sample rate, which is required if the - final
command-line parameter is used to indicate audio is being piped into direwolf (such as
from SDR programs like rtl_fm) such that DireWolf doesn't know what the sample rate is.
Also, the receiver must have adequate audio passband; direct discriminator output (such
as the 9600 audio output on a standard data port) or a sufficiently wide-band Software-Defined
Radio (SDR) should be used to ensure the signal is not distorted beyond decodeability.
When using the AIS decoder plugin for YAAC, it is recommended not to use the
-A option to DireWolf, as YAAC can do the conversions for itself, so using
this option will cause duplicate displays for ships using the different AIS-to-APRS
translation algorithms in YAAC versus DireWolf.