Dan, one of the navy blogs has said that USA already has some stuff in the Black sea which can do some stuff if it has to. That was about it, and it has passed off the page now. At the bottom now is:

The Telegraph is reporting a Russian warship is patrolling the Black Sea coastline around the port of Poti and was said by coastguard officials to be enforcing a 50-mile exclusion zone.

“We haven’t tested what the Russians will do, so I suppose there is a blockade,” said Alan Middleton, the port’s British general manager, who is from Bristol.

The events of the last week have dealt a huge blow to confidence in the port, which handles metals and commodities transhipments to Central Asia, and in Georgia’s wider economy.

“It is certainly force majeure for ship owners,” Mr Middleton said.
Ukrainian news is running several stories about “a big Ukrainian ferry with 48 crew members on board [that] was blocked in the Georgian port of Poti.” The Ukrainian government is working with Russia to allow for the ship to get to sea.