Being a native Russian-speaking I would say that a similarity between Greek and Cyrillic-based languages is not that obvious (although does present, of course). For example, an average Russian-speaking can not read Greek letters (although may find some Greek letters to be "quite similar" to cyrillic). My personal solution is to learn Greek alphabets. After doing so, it's not a problem to read Greek map or names of Greek ships. So, I would suggest to do something similar in respect of Cyrillic-alphabets, which would enable one to read Belorussian, Bulgarian, Russian, Serbian and Ukrainian names.