From fukuoka to bussn

Hello,

I’m an exchange student and would like to take to boat from Fukuoka to Busan. My visa is a single entry so I need to fill the speacial re-entry permission before I leave Japan for a short time travel. I know that at the airport there surely are documents for this but I couldn’t find sure information that is is tge same way when leaving with a boat. Is there anyone here that knows anything about this?