According to Tribeca Shipping, a port operator, on February 5, there were 51 vessels in the queue with their cargo being about 38.7 million barrels.
In addition, tankers that leave the Black Sea, have to wait for about 16 days, which is a major change since the usual waiting time was 5-6 days maximum since 2014.
When taking the opposite direction, the waiting time takes approximately 14 days, in comparison to the usual 6 days.
The delays are mostly because Turkey introduced new rules for the passage of vessels in September 2018.
Consequently, there has already been a vessel jam in the Turkish straits in January, as the new rules focused on vessels being escorted by tugboats.
In conclusion, additional to the tugboat rules, the weather conditions aren't helpful either, worsening the situation.