The requested vessel with name PORTUNUS and MMSI:31981570 and IMO:0 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
PORTUNUS N/A 244050348 Nov 05, 2017 08:40 UTC
PORTUNUS N/A 205491790 Aug 21, 2016 09:19 UTC

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