I'm not too familiar with Dubrovnik, but from what I've seen on google and wikipedia, Belushya Guba's not like that. Belushya Guba itself is along the coast, but the wizarding establishment is inland a bit, as it's on the outskirts of muggle Belushya Guba. It's also within a compound of four large buildings, and there's no real exposure to the sea.
I hope that answers your question.