The requested vessel with name RIVER THAMES and MMSI:0 and IMO:6525727 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
RIVER THAMES 8601563 577232000 ORISTANO Feb 24, 2018 15:28 UTC

Also, you may try to find the vessel in our comprehensive Vessels Database or track this ship on the map.