Initially built between 1895 and 1907, Zeebrugge’s enormous artificial harbour had been in use less than a decade when Allied forces sank ships to block its entrance, thus preventing German naval use during WWI. Further bombed in WWII, the harbour finally reopened to sea traffic in 1957. The departure terminals for overnight P&O ferries to Hull are 2km north of Zeebrugge-Strandwijk tram stop, or 3km from Zeebrugge train station. It’s an unpleasant walk. It's far better to arrive directly at the boat on the connecting bus from Bruges bus station.
Zeebrugge's play for the tourist euro is Seafront, whose main attractions are a parked Russian submarine and a lightship (sister to the one you'll see in Antwerp).