It was run by the Union Steamship Company of New Zealand, using the identical 462 ton ships Hawea and Taupo. The company’s last ship on the crossing was the 400-passenger Tamahine, which was famous for her permanent list and unsettling corkscrew motion in heavy seas. Despite this, the ferry operated from 1925 to 1962.

By this point, the 350km passenger rail service from Waitohi/Picton and Ōtautahi/Christchurch had been in place for seven years and the Government decided the ferry service should be taken over by the Railways Department. It introduced the country’s first roll-on roll-off rail and vehicle ferry, the Aramoana. Cargo that had taken a day to load now took an hour: This caused a veritable transport revolution and by 1974, coastal shipping had disappeared.

During the 1970s, the Government added three more ships: The Aranui, Arahanga and Aratika. The Arahura, introduced in 1983, sailed until 2015. The ferries’ trademark dolphin logo was introduced in the 1980s and depicts famous Marlborough Sounds dolphin Pelorus Jack, which for 25 years escorted Raukawa/Cook Strait ships.

New Zealand railways were privatised in 1993 and bought by Americans. The railways were rebranded as Tranz Rail, and the ships were marketed as “Interislander” ferries. In the mid 1990s, attempts were made to shorten the 3-hour plus journey across the strait with fast catamarans. The privately-owned Top Cat proved unreliable and the Interislander’s own attempt, The Lynx, had a huge wake that tore up the Marlborough Sounds coastline. In 2005, after a public campaign to remove the fast ferries, the last one was withdrawn.

In 2006 Raukawa/Cook Strait freight shipping company Strait Shipping started its own passenger ferry service, the Bluebridge. Today both the Interislander and Bluebridge ferries make daily crossings both ways across the Raukawa/Cook Strait.