Online AIS Message Decoder
This web site allows you to enter AIS messages received from an NMEA-compliant AIS receiver - and have them converted to a more human-friendly format. The service is free, but be aware that each message supplied is stored forever for testing and debugging purposes (it will never be given to anyone).
You can for instance try with these sentences:
!AIVDM,1,1,,A,18UG;P0012G?Uq4EdHa=c;7@051@,0*53 !AIVDM,2,1,0,B,539S:k40000000c3G04PPh63<00000000080000o1PVG2uGD:00000000000,0*34 !AIVDM,2,2,0,B,00000000000,2*27
Decoding is performed by open source library 'AISmessages' - https://github.com/tbsalling/aismessages