Bulgaria's transport ministry expects the capsized cargo ship Horiv to enter the country's area of responsibility within the next 24 hours. Officials are tracking it around the clock.
A Navy ship will be sent to inspect the vessel. Transport minister Georgi Peev and defence minister Dimitar Stoyanov met and agreed on options to keep shipping safe.
Regular notices to mariners will follow.
The Horiv called for help on 23 October after a suspected drone strike. It was then 13 nautical miles off the Romanian coast near Constanta.