This was reported by Vesselfinder, to which the CTS refers.
The publication notes that the Russian ferry was heeled over (three ballast tanks were flooded) and returned to the Bulgarian port of Varna for inspection.
At the same time, New Raouf continued to move toward Turkey and is now near the entrance to the Bosphorus.
According to Bulgarian media, the vessel is owned by Liberian New Raouf Shipping Ltd and operated by Romanian Daytona Management.
It is specified that the Slavyanin ferry has been running for about 10 years on the Varna-Caucasus line, transporting railroad tanks. Vesselfinder notes that it is unclear what it was doing near Shabla/Tyulenovo because the line to the port of Kavkaz runs in a straight line in a more easterly direction, while the Russian vessel was moving somewhat north.