The requested vessel with name YEOSU 4 and MMSI:0 and IMO:9378890 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
YEOSU PIONEER 9231066 440168000 >KR YOS WS Feb 19, 2018 02:54 UTC
YEOSU NO.3 N/A 440310550 Apr 06, 2016 04:22 UTC
YEOSUCHOSUN1 N/A 440008030 May 31, 2016 03:06 UTC
YEOSUGYENGGOLFRESCRT N/A 440325250 YEO SU Jun 11, 2017 10:31 UTC

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