The requested vessel with name RYOKO MARU and MMSI:0 and IMO:8028943 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
RYOKO MARU 9789087 431008051 >JP ANE OFF Oct 19, 2017 18:46 UTC

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