Catching Ferry

We are getting the car ferry from Split to Hvar next Saturday and plan to get on the 14.30 ferry. How much time in advance do we need to get to the port to make sure we do get on that ferry?

I can't give you any details, but when I boarded the car ferry (on foot) in Dubrovnik last month, there were traffic jams around the port, while at other times the traffic around there was very light.