Newport Ship could be Wales' answer to the Mary Rose
A salvaged 15th Century ship has "significant potential" to do for Wales what the Mary Rose did for Portsmouth when it goes on show, an archaeologist says.
The remains of the vessel were found preserved in mud in a Newport riverbank in 2002.
One of the men who is restoring it said it will be the world's largest ancient ship rebuild project.
Newport council said it hopes to display the ship in a prominent place.
Toby Jones, project curator for the Newport Mediaeval Ship project, said 2,500 timber pieces had to be restored before the ship could be rebuilt and put on show.
The team working on it say they hope it could finally be put on public display by 2025.
They estimate it could attract up to 150,000 visitors a year to Newport, boosting the south Wales economy by £7m a year.
Mr Jones said the "unique" attraction could emulate the Mary Rose exhibition of Tudor king Henry VIII's 16th Century flagship naval vessel - renowned as one of the world's best maritime displays with its own £35m museum in Portsmouth.
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"Everyone knows about the Mary Rose but the Newport ship is even older than that," he said.
"The Mary Rose has had a measurable impact on Portsmouth and its economy - and this will be the same here.
"The Mary Rose is the world's 16th Century ship, the Vasa in Sweden is the world's 17th Century ship - Newport will be the world's 15th Century ship.
"Newport will be in that top level of important ships on display around the world. There'll be nothing else like it in the world.
The world's biggest 3D jigsaw
"The Mary Rose and Vasa were never taken apart, they were conserved and put on display whole - we have the largest ship that has ever been attempted to be put back together."
Putting the Newport Ship back together is described as the world's biggest 3D jigsaw puzzle, just without any instructions.
It is 18 years since builders of a new theatre in Newport had an almighty shock by discovering the remains of a ship in the banks of the River Usk.
Historians now believe the Basque country-built vessel, launched around 1449, was involved in the "lucrative wine trade" between Portugal and the Iberian peninsula and Bristol.
It is thought the 30m (98ft) long, 400 tonne medium-sized boat was having a refit in a Newport inlet between 1468 or 1469 when its moorings broke.
A lot of the oak planks and iron were salvaged before the tide hid the stricken ship, but a third of the ship succumbed to its muddy grave.
It lay buried under Newport's riverfront, oblivious to anyone walking above it, for more than 550 years in "perfect cold, dark and wet conditions" before a stroke of archaeological luck.
The painstaking restoration - which has required the equivalent of 17 years of hard labour - has been diligent and precise but it has not been quick.
Why does conservation take 25 years?
Now it could take another five years at least before the ship finally goes on show to the public.
"The preserving process for each of the 2,500 planks - some of which are 13m long and half-a-tonne each - is about four to five years," explained Dr Jones.
"Each plank is stored in water until they are wax-treated so the wood can absorb it and replace the water. After about four years, they are freeze dried to ensure the best restoration.
"We can do about 100 planks at a time. We've done 1,900 planks so 600 to go."
Archaeologists have been focused on preservation in the 18 years since the ship was unearthed but now their attentions are turning to reassembly
"We think we could start reassembly in three or four years," added Dr Jones.
"There's no book to follow so we'll have to make it up and hope it works.
Where will the Newport Ship live?
Historians can only begin putting the ship back together - which itself could take three to four years - when a home is found due to the size of the reassembly project.
The Friends of the Newport Ship, volunteers who support the campaign, say £9m of public money has been spent so far and they now want authorities to commit to a permanent home for their crown jewel.
Newport Museum in the city's shopping centre is a possible option but no final decision by Newport council has been made.
"There'll be nothing like it, it'll be a powerful attraction and economically beneficial.
"Economic impact assessments predict between 100,000 and 150,000 people a year and a £7m benefit to the local economy.
"The city are looking for sites to house it and I'm optimistic. We need a very large space with a controlled warm, dry environment."
How do you house a 15th Century ship?
Historians have been helped by famous medieval boat exhibitions to learn restoration lessons from Mary Rose and Vasa experts.
"One problem we know from other archaeological displays is they start sagging in museums," said Dr Jones.
"They're not happy out of water so the solution is to support it and we've a unique opportunity because the ship has been taken apart into thousands of pieces."
Newport Ship archaeologists have been working with Swansea University's engineering department to create a purpose-built cradle.
"We want every visitor to see the ship from every angle without any view being blocked so the idea is to build the ship around an almost invisible cradle," added Dr Jones.
"It will provide comprehensive support which will take the weight of the ship so it can be enjoyed by generations."
Newport council said it had managed the project to conserve the vessel for a number of years with financial support from the Welsh Government.
"It is council's ambition is to display the ship, and artefacts, in a prominent location in the city subject to funding and a suitable location being found, once the conservation and restoration work has ended."