The space shuttle of the ocean and more complex than a fighter jet, the Attack class submarine will be a leading light in Australia’s Defence Force.

It’s the most complex design and build on Earth: one million pieces working together in an engineering feat of perfect harmony to create a 5000-tonne powerhouse tasked with defending Australian shores. The $50 billion Attack class submarine program – the largest defence acquisition in Australian history – is just three years into the 50-year process of bringing this amazing program to completion. From weight to weapons, food to fitness, every aspect of life on board must be analysed and tested before construction can even begin.

Breathe easy

“I talk about it being a village or town underwater, says Gary Swarbrick, chief technical officer for Naval Group Australia with more than 30 years of experience working on submarines under his belt.

“Everything you need to do in your normal life, you need to do on a submarine hundreds of metres below the surface. All these things you take for granted – like breathing. You breathe in and you breathe out and you don’t think about it because the trees take care of that and that’s what you do. But when you’re hundreds of metres underwater, within a couple of hours if you didn’t do anything, there would be no oxygen and really high carbon dioxide and everyone would die. So just that simple act of breathing has to be engineered, thought about. We have machines that produce oxygen, ma- chines that remove carbon dioxide, which have to work in tandem with the ventilation and air conditioning systems.”

Daily hygiene must also be planned.

“Just brushing your teeth – the water is made from seawater so there’s a plant on board the submarine that turns the seawater into freshwater,” Swarbrick says.

“When you spit it out into the sink, we have to collect that in a tank and store it. Any gasses or nasties that come off of that, we have to deal with because it’s inside a closed environment. Then there are rules of the sea which mean we can’t discharge it anywhere we want. So all of this has to be thought about, designed, engineered, constructed – just to do those everyday things. And you want to do that in as small a space as possible because the smaller the vessel is, the harder it is to detect, and it takes less power to move through the water. So you’re constantly trying to pack all these things in. For me, when you think about that and put all that together, it’s fascinating.”

Designing the future

If designing and building 12 state-of-the-art Attack class sub- marines for the Royal Australian Navy isn’t enough of a challenge, the longevity of the program makes things even more complicated. The first completed submarine isn’t expected to enter into service until the early 2030s and the last by late 2040. Given the rate at which technology can change, it means engineers have to allow for considerable flexibility in their design plans.

“We talk to the Navy, asking where they want to go with the submarines in the next 10, 20, 30 years and what kind of things they want to see,” Swarbrick says.

“That informs us as to what our technology roadmap needs to look like. For each submarine, we can change the design, the parts to keep it relevant and up-to-date. So it’s a constant rolling program.”

But before construction can begin, engineers need some- where to put these mammoth vessels together.

“Not only are we designing a submarine and ultimately building it, we have to build a shipyard within which to build it,” says Paul Pearce, test qualification and acceptance officer for Naval Group Australia.

“Not only that, we have to establish a supply chain in Australia to build the submarine. Those three chunks are each very involved and require thousands of people and varying expertise. So we have to orchestrate this whole project in parallel and that’s what makes this really challenging.”

Safety first

One of the most important aspects engineers must look at when designing the submarines is on-board safety. Operating hundreds of metres under the water makes escape challenging should something go wrong.

“We have humans in these things and we have to protect the men and women serving on them,” Pearce says.

“It’s a very confined space so when things go wrong, they escalate very quickly. A lot of thought is put into making sure we’ve considered all the different ways things can go wrong, whether it be a fire, flood, toxic gases ... We have to think what we can build into the design now to make sure those things don’t happen as best we can, which makes the design even more complex.”

The right balance

Ensuring the 5000-tonne vessel will submerge and then surface when required relies on a whole host of those million parts working in harmony with each other. One of the biggest challenges for engineers in building a submarine this large is what’s involved with keeping its engines running.

“We’re not making it as big as it is because we want to have the biggest submarine; it’s because Australia is so far away geographically from everywhere else,” Swarbrick says.

“It’s a conventional submarine so it has diesel engines and batteries: it needs a lot of fuel and a lot of batteries to go where it needs to go.”

Those fuel and batteries, of course, take up valuable space.

“Then there’s the tanks for water and the machines that make the air, the amount of food we’ll need on board ... then the cascade starts,” Swarbrick says.

“And the crew themselves,” Pearce adds.

“Each item brought on-board adds weight. Because a submarine is so dense, you want it as close to its neutral buoyancy as possible, which means it just sits in the water where it is, so you need to know almost to the kilogram the weight of the submarine. That means when a sailor brings along an iPad or a couple of books or a guitar, that all has to be accounted for, which is quite amazing.”

Testing times

Before any one of those million parts is cleared for use on the submarine, it must undergo rigorous testing.

“We’re going out looking at suppliers and when a product looks like it meets our specification, buying samples and then going to labs around Australia where we can do all kinds of full-on testing, pressurising them to see how they’ll react underwater, shock testing ... We put the equipment through its paces and if it survives all of that, then we can think about putting it on the sub- marine,” Swarbrick says.

“Steelmakers, with years of experience and extensive knowledge, have come together to create a steel grade to suit the requirements of the Attack Class submarines,” says fluid technologist Joisbel Castro Ramirez.

“Making sure our steel has the right properties and has the resilience to endure the different missions the submarine will be required to perform is paramount.”

The technical design and construction requires specific testing conditions which existing laboratories in the country cannot currently provide. Not to be swayed, Naval Group Australia is taking matters into its own hands.

“We’re looking to build a standalone, land-based test facility based out of the shipyard that will produce a new capability that doesn’t exist in Australia right now,” Pearce says.

“It will test the propulsion and electrical system of the submarine within a building to make sure everything works. As far as we know, it’s the first time in the world this has ever been done for a conventional submarine, and it’s all happening here in South Australia.”

Growing workforce

With the Attack class submarines expected to remain in service until the 2080s, South Australia can be confident of decades of employment for generations of workers.

“It really is its own ecosystem,” Swarbrick says.

“We have lots of heavy engineering tasks such as constructing the pressure hull, and classical engineering tasks such as running cables for electrical systems, right down to the design of the submarine’s computer control system, which is massively complex in itself. It really is all-encompassing.”

Originally published in Future Adelaide: Nerves of Steel