Also the Sea of Azov is very shallow. Wiki gives a mean depth of 7m (23 ft). It is too shallow for most warships.
A couple of years ago some US politician suggested sending a couple of Arleigh Burke class destroyers into the Sea of Azov as a show of force/show of support for Ukraine. Duh. An Arleigh Burke class has a 9.3m (30 ft) draft
