This is not a maritime disaster I’m witnessing. David Allan is designed to do this, and the ship’s hull is cleaved apart a number of times every day.

Still, it’s a disconcerting sight, to be peering at the swell through a ship’s split hull.

David Allan deliberately opens itself to the sea so that other ships’ hulls don’t become stuck on the bottom of Newcastle harbour. For David Allan is a dredger, picking away at the Hunter River’s muddy mouth and keeping clear the commercial shipping channel and berths in what is one of Australia’s busiest ports.

OF the more than 2200 ships that cruise in and out of Newcastle harbour each year, none is seen more often than David Allan. It is perhaps the most visible vessel on the water, for it seems to be a constant presence.

Even the most casual observer of harbour life would have noticed this 71-metre vessel, as it ploughs in and out past Nobbys or slowly picks its way around the port. 

“It’s just like a great, big vacuum cleaner,” says Keith Wilks, Port of Newcastle’s executive manager operations and infrastructure.

The ship’s official title is a trailing suction hopper dredger (TSHD), which, Wilks explains, is essentially what David Allan does; it drags a trail, sucks in what it stirs up, and that pours into the ship’s hopper. The process is dredging.

To see the TSHD in operation, Keith Wilks and David Allan’s crew of seven invite the Herald on board. Wilks can quickly find his feet on a ship’s deck. He went to sea for the best part of a decade and, before this job, he worked for the tug company Svitzer and was involved in the Pasha Bulker salvage operation in 2007.

David Allan is berthed at Dyke 6, on the edge of the former BHP steelworks site, in the Hunter River’s South Arm. 

On the other side of the river, along the Kooragang shore, are a few of the reasons David Allan’s work is crucial.

A row of bulk carriers is being loaded with Hunter coal, each tonne pushing the massive hulls ever closer to the harbour bottom. By the time some of these ships depart, there may be clearance of little more than a metre in the channel. David Allan provides certainty for those on board that there’s enough water under them in the port.  

“A ship has to have uniform depth; it’s critical in keeping a port going,” Wilks says.

The dredger maintains the channel at a depth of 15.2 metres from the breakwalls to the Kooragang 10 berth in the river’s South Arm, which is a distance of about nine kilometres.

“It’s a lot of channel for us to maintain,” Wilks says. David Allan also keeps clear 20 ships’ berth boxes, and the Basin area off Carrington to a depth of 12.8 metres.  

David Allan is on the harbour seven days a week. Its role is ceaseless, flowing on as surely as the river that makes the ship’s place in the port so necessary. The Hunter carries the silt into the harbour, and the dredger clears at least some of it.

The Port of Newcastle is licensed by the federal government to remove 650,000 cubic metres of silt and sand a year. On average, Wilks says, about 500,000 cubic metres are removed annually. About 30,000 cubic metres of sand are removed from the harbour entrance. The rest is silt that has come down the river.

“We help it on its way, because it’s coming anyway,” Wilks says. “It’s fair to say the Hunter River is a fairly disturbed system.”

The river becomes more disturbed after major storms, and what is washed into the Hunter upstream will most probably show up in the harbour, creating even more work for the crew. After the 2007 “Pasha Bulker” storm, Wilks says, there was so much sediment the channel lost about a metre and it took six months of dredging to clear.

“Probably in nooks and crannies, they’d still have [silt from] the Pasha Bulker storm in there,” he says.

“Most of the silt comes down the North Arm,” he explains, because it is broader and shallower than the South Arm, and the particles are carried along more quickly, before a lot of it is dumped in the slow sweep of the river off Stockton known as the Horseshoe.

That is the area the dredger is bound for on this day. The port’s hydrographic survey team has been measuring the harbour’s depth in the vessel JT Gowlland, and its data determines what parts need dredging. So that information has helped set the course for David Allan.

The ship doesn’t begin at one end of the port and works its way down. Rather, “we jump around according to what needs dredging,” explains Wilks.

“And dredging can’t get in the way of shipping movements.”

After he has coaxed David Allan away from the wharf and we cruise downstream, Trent Hollis, who is the ship’s master today, points to patches of pink on a computer screen. That’s what has to be dredged. Hollis will guide the ship, while crew member Mick Crabb, who is sitting beside him, will operate the drag head and pump. 

Crabb has been a crew member for about six years, and before this, he worked on gas tankers and rigs, mostly off Australia’s north-west coast.

The dredger cruises at under two knots, while the drag head is lowered over the starboard side and into the mud.

“The first law of dredging - don’t go backwards,” says crew member Colin O’Donnell, who has worked on the ship for 25 years.

The first law is followed, the pumping begins, and a slurry pours into the hopper. It looks as though the harbour is being turned upside down, as the mud and water flow in. Keith Wilks says the sediment is sampled and tested before it is pumped up and disposed of out to sea.

“What we’ve seen over time is a general improvement,” he says, citing the closure of the BHP works as contributor to a cleaner harbour bottom.            

The hopper, which holds about 1100 cubic metres, is quickly filled.  

The ship’s bow points to the immensity beyond Nobbys, and Trent Hollis hands over control of David Allan to crew member Jon Baxendale to guide her out to sea.

“She’s not too bad, very responsive,” says Baxendale, a second-generation mariner, as David Allan picks up pace at the touch of open water. “And I get a kick out of going to sea; it must be in the blood.”

The dredger doesn’t head out when the sea is angry. But today, the swell is about one and a half metres, and David Allan nods and gently sways, as Baxendale steers her to the disposal ground. The site is a one kilometre-square area, containing, on a chart at least, 100 “boxes”. This load is to be dumped above “Box 15”.

Trent Hollis orders a turn to starboard to “slow it down for the hole”.

“Coming around!,” responds Baxendale.  

David Allan steadies and then her hull parts on large hydraulic hinges.

“It splits 27 degrees,” says Colin O’Donnell.

The deck rises like a seabird’s wings, exposing the swell. One of the crew later says that as a mariner, it’s a disturbing sight: “Ships aren’t usually meant to split open.”   

Within about 10 seconds, the hopper is empty, and the hull is sealed once more. David Allan pushes towards the harbour entrance. The dredger makes this voyage on average five times a day.

On the way back in, Colin O’Donnell scans the water. Despite him having made this voyage thousands of times, he mutters, “there’s always something different happening on the water, always something”.

Brought up in Kurri Kurri, O’Donnell went to sea in the 1960s as a cadet on the Iron Wyndham, part of the BHP fleet that would load and unload in that stretch now occupied by David Allan.  

He has seen remarkable changes on the harbour and along its shores, a lot of it shaped by this ship he is on. When O’Donnell joined the David Allan in 1992, the BHP steelworks was still operating, and there were only a couple of coal-loading berths. He is amazed by the transformation of the South Arm, particularly at the Kooragang berths upstream, where great ships are nudged into the bank.

“All that up the river was just about swamp,” he recalls. “You could walk across parts.”

But some things don’t change.

“It’s one of those things that if you come back in 150 years, they’ll still be dredging the port of Newcastle,” O’Donnell muses.

If you went back more than 150 years, there was dredging in the port.

In the late 1850s, Edward Moriarty, who was the engineer for Hunter River Improvements, devised a plan for developing the harbour. From 1859, continuous dredging took place on the harbour. Within two years, he could report that parts of the harbour had been deepened by 10 feet, or just over three metres.   

Yet maintaining the port was an unrelenting challenge then, as it is now. In 1889, The Illustrated Sydney News reported how “a good safe enclosed harbour has been secured; but unfortunately, owing to the immense quantity of sediment brought down by the Hunter River, dredging operations have to continually kept up”.

The same story could well be published today.

“This never ends, we’re always on the river,” Keith Wilks says. “Unless you stop erosion, it’s just going to keep on coming.”

HAVING helped clear a path for other ships, David Allan then stays out of their way in the port.

Trent Hollis is alerted that a bulk carrier, Star Artemis, has just “lifted off” from the Kooragang 9 berth and is heading down the South Arm. He has to work out where to pass the fully laden ship.

“We can’t stay in the channel,” Hollis says.

Hollis peers at his paper charts then at a computer screen that marks other vessels on an automatic identification system, before looking up and out.

“Whatever we’re looking at electronically, you verify it by what you see out the window,” he explains.

The 44-year-old has been on ships for almost half his life. He’s been on water for much longer. He grew up by Lake Macquarie. Hollis has been on David Allan for four years and is the Mate and Relief Master.   

“It’s a good position,” he says, “and it can be stressful at times. The biggest stress is being aware of other vessels . . . You’ve got to be a step ahead.”

Just below Walsh Point, near where the North and South arms meet, Trent Hollis takes control to pass the approaching bulk carrier. He takes the dredger just out of the channel, and Star Artemis lumbers by. 

“I take a lot of pride in this,” says Hollis. “We realise how important it is to maintain those draughts of the big vessels.”

For if ships are stuck, a lot of trade would be left high and dry. In 2016, almost $16.7 billion worth of exports passed through the the port. While coal accounted for the bulk of that, everything from wheat to aluminium was shipped out. What’s more, almost $2 billion in products were imported through the port.  

“If we lost depth [in the port], then farmers can’t expect their wheat to be exported,” says Keith Wilks. “A lot of people rely on this port.”

So David Allan, he concludes is more than a constant presence on Newcastle harbour; it’s a vital one.

“It’s playing an important role in keeping an economy going,” Keith Wilks says, “and not just in the region, but also in the state and the nation.”