One World Karadeniz (previously Stena Explorer) is a former high-speed ferry owned by Stena Line and which operated on Stena's Holyhead–Dún Laoghaire service between Great Britain and Ireland until 2015. As of 2015 the ferry is owned by Karadeniz Holding to be used as a floating office in Karmarine shipyard in Yalova, Turkey. It is a member of the HSS 1500 class of high-speed ferries introduced and developed by Stena Line from 1996 onwards. The HSS 1500 class vessels became the largest catamarans in service in the world.