Earnslaw back sailing after 'nerve-wracking' engine overhaul

Vintage steamship TSS Earnslaw is resuming its regular sailings from Queenstown to Walter Peak on Wednesday after a five-month engine overhaul.

Owner RealNZ said it had undergone the most intensive survey in the vessel's 113-year history, with both 16-tonne engines removed and transported to Invercargill to be dismantled, cleaned and reassembled.

RealNZ marine asset manager Matthew Slover said it was a nerve-wracking exercise.

"We held our breath a little bit, because the space under the engines had never been accessed before. But then we found that, thanks to all the lubricating oil used in the engine room, the structure was in remarkably good condition for a vessel her age," he said.

RealNZ said crews replaced several hull plates, upgraded bearings in the main engine connecting rods and completely re-tubed the boilers - replacing the 300 tubes that heat water to generate steam.

Earnslaw was among the world's largest and oldest coal-fired steamships still operating.

RealNZ chief executive Dave Beeche said it was an iconic piece of New Zealand's history and that came with a deep sense of responsibility.

"As kaitiakitanga of this precious taonga, I'm really proud of the care and expertise that's gone into this complex and unique project," he said.

RealNZ said over the past few days the ship had undergone successful trials on the water and on Wednesday it was due to be handed back to the company's guest experience crew.

The revamp would keep the the Earnslaw steaming smoothly for years to come while preserving a living piece of history, RealNZ said.