gimpy117,
To start with, there is some traffic in the Black Sea in the stock campaign but not much.
eweber created a number of mission for the 30th flotilla in the Black Sea for stock SH3. Take a look here
http://www.subsim.com/radioroom/show...ighlight=Black
I did not notice any game-killing issues when played them.
If you do not want to use big mods, the last version of U-boat War Ace 2 (do not mix up with WAC) should have some Black Sea operations if I remember correctly. It is relatively small download and can be still found on my SH3 web site. Again I do not remember (did not play or pay attention to SH3 lately), if the download is a complete package or you would need to download some extra mods from the same page. It should say in Readme.