Ferry to kagoshima

Hi!
I'm planning a trip in may, and i wanted to travel from naha to kagoshima using the ferry as it is a bit more eco friendly. But, it seems that the timetable is not available yet, so i can't really plan my trip fully without that.
Do anyone has any info on when there is one? Is taking the ferry is a good idea at all?
Thank you!

by louna312