Detailed 3D maps of the bottom of the Swan River have led maritime archaeologists to a sunken barge right in the heart of Perth that has lain unexplored for about a century.
Patrick Morrison, who is completing a doctorate in archaeology at the University of Western Australia, said the find was made after studying maps of the riverbed released by the state government.
“We had seen … some of the shipwrecks that we knew existed, but we also saw some interesting lumps,” Mr Morrison told Nadia Mitsopoulos, on ABC Radio Perth.
“We ended up diving one of those after checking on the sonar, and it was a shipwreck … it could be about 100 years old.”
Mr Morrison was accompanied by maritime archaeologists Jess Green and Ian McCann on the dive.
Mr McCann said 37 wrecks had been discovered in the river over time, but the newly available government data was enabling researchers to find fresh areas to target for exploration.
The trio is now keen to explore the river bed further and to find out more about the boat they found last weekend.
Ian McCann and Patrick Morrison have been exploring the Swan River.(ABC Radio Perth: Emma Wynne)
“It’s about 20 metres long, and it’s in about 14 metres of water,” Mr Morrison said.
He said it appeared to have similarities to a known wreck in Fremantle, a barge called the Mayfield built in the 1890s, which was used to bring goods up and down the river and was wrecked in the 1940s.
“Now we’re going to be working with the museum to see if we can identify what the wreck is, but also what decade it was from and what industry it was involved in,” Mr Morrison said.
The team will also gain information from the items left on board when the boat sank.
A demijohn spotted on the wreck means it likely hasn’t been explored before.(Supplied: Patrick Morrison)
“We saw items there that we will definitely be able to date,” Mr McCann said.
“For example, there are a couple of what we call demijohns. These are about five-gallon (19 litre) ceramic containers that would hold things like whiskey or beer.
“They’re sitting in the wreck [and] we can identify those for sure. But there’s lots of other lumps and bumps, little hints of things.
Researchers found the wreck while examining 3D mapping of the floor of the Swan River.(Supplied: Patrick Morrison)
“If we gently fan away that silt, we’ll be able to identify what those items are.
“That’s also why we know this wreck hasn’t been dived before, because those are the kinds of things that people like to collect.”
The team is also keen to find out how old the wreck is, because that determines whether it’s subject to protection under the state’s Maritime Archaeology Act.
“The wrecks before 1900 are protected but wrecks after that aren’t,” Mr Morrison said.
The team used a side-scan sonar to pinpoint the right place to dive.(Supplied: Jess Green)
The team think it’s likely the boat was sunk deliberately, as the river was often used as a dumping ground for unwanted property in the early 1900s, and the wreck was found in one of the deeper parts of the river.
“Back in those times it was expensive to break up a ship … you’d have to take it to a boat yard to be broken up and it would cost money,” Mr McCann said.
“It was a lot easier to take it to the middle of the river in the middle of the night and open up any holes or smash a hole in the side and let it sink.”
The wreck is at 14 metres depth and covered in silt.(Supplied: Patrick Morrison)
And it wasn’t just boats that were pushed into the murky deep — cars and even buildings could end up in the river as well.
“People pushed factories into the river, just to demolish them and get them out of the way,” Mr Morrison said.
“There’s a soap factory down in [the river in] Fremantle, there’s all sorts of stuff.
“There are old pumphouses … you can find on the riverbed, where they’ve been pushed over.”
It’s believed the wreck is likely a barge.(Supplied: Patrick Morrison)
While the wrecks are interesting finds, ultimately the team have their sights set on archaeology that stretches back much further.
“These wrecks are 100, 200 years old, but Aboriginal people have been here 50,000 years,” Mr Morrison said.
“They’ve been using this river probably for most of that time, and the river has changed course.
“We’ll be finding, probably at some point, both maritime sites and also sites that used to be on land that have now ended up preserved on the riverbed.
“Part of this project is to work out a process where we can start to identify these Indigenous sites underwater.”
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