Captain Alan Stockwell on one of the tug boats pulling Prelude
Captain Alan Stockwell is on board the lead tug pulling Prelude

As dawn breaks over the green hills surrounding Geoje harbour in South Korea, Captain Alan Stockwell is giving instructions to his team on the radio of his tugboat.

The 40-year veteran of the marine services industry is leading a team of tugs, pulling the world’s biggest floating liquefied natural gas facility, Prelude, from its shipyard in South Korea to gas fields off the coast of Western Australia. It is a journey of some 5,800 kilometres (3,600 miles).

“This is the world’s biggest tow and far and away the highlight of my career,” says Stockwell.

Prelude is 74 metres wide and 488m long. It is being towed by three tugs, each more than 75m long. A fourth tug acts as an escort.

Prelude will cool natural gas and convert it into liquids at sea. Once it reaches its destination, it will tap into natural gas resources in the Browse Basin, an area 475km (295 miles) off the coast of Broome in Western Australia.

The liquefied natural gas that Prelude produces will be sold to customers around the world.

Precision start

The bridge on Stockwell’s lead tug is like a busy newsroom. Radios crackle and phones ring. Weather reports appear on screens. “We're in constant contact with typhoon monitoring centres in the USA and Japan,” says Stockwell.

Prelude now faces a journey of at least a month to its new home off the coast of Australia. The most difficult part was at the beginning, when nine additional tugs carefully coaxed Prelude from the harbour through a narrow U-shaped channel into open waters.

“The channel has strong currents and Prelude is very large, so you can imagine it’s like a fast car turning a tight corner. The manoeuvres had to be very precise,” says Captain Gerald Seow, Chief Executive of PACC Offshore Services Holdings, the Singapore-based marine services company in charge of the ocean tow.

Willem Keij, a Shell engineer responsible for the tow, experienced mixed feelings as Prelude departed. “I’m excited, of course. But I also feel a tremendous sense of responsibility,” he says. “All the years of planning have finally led to this moment: we are the team taking Prelude safely to Australia.”

Keij is one of 160 people staying on board Prelude during the journey. He describes his role as “the spider in the web,” gathering information from each of the tugs and from Stockwell, helping decide which route to take depending on the weather, and communicating with the Shell project team in Perth, Australia.

Prelude pulled by tugboats after leaving Georje harbour
Prelude left Geoje harbour pulled by a team of tugboats

Refuel on-the-go

At top speed, Prelude will be travelling at around five knots, about the same pace as a fast walk. Along the way, the convoy may encounter small fishing boats and other vessels that Prelude will need to safely avoid.

The convoy left Geoje at the end of June and moved into the East China Sea, across the Korea Straits. It will then go through the Philippine Sea, past the islands of Indonesia and across the Timor Sea. At the Indonesian archipelago, a fifth vessel will meet the convoy to help refuel, replenish supplies and replace the crew.

Once Prelude reaches its final destination, work will start to plug it into the undersea infrastructure. As 16 pre-laid mooring chains are lifted from the seabed and attached to Prelude’s 93-metre high turret, a sixth towing vessel will join the five boats to keep the facility in place.

Because Prelude sits in an area of cyclones and strong ocean movements, the turret will allow the facility to pivot safely with the prevailing current and wind. Once operational, this ability to act like a weathervane means Prelude can ride out storms without having to disconnect the flexible pipelines that feed in gas from deep below the waves.

When all 16 chains are in place, Prelude will be considered storm-safe and the work of the tugboats will be officially complete.

Meeting demand

Keij, Stockwell and their teams have played a critical role in this latest step for Prelude, but it’s the start of an even bigger journey.

In the next two decades, Prelude is expected to produce 3.6 million tonnes of liquefied natural gas a year, as well as liquefied petroleum gas and condensate, a light oil. It is also expected to create 350 direct jobs for Australia.

Keij still marvels at the technology. “One-third of the world’s gas resources are in remote areas. With this floating liquefied natural gas technology, we can now tap into those fields,” he says.

Crossing cultures

Workers talking to each other

Prelude was built at the Samsung Heavy Industries (SHI) shipyard in Geoje, South Korea.

The construction team included 20 nationalities, from countries including Australia, South Korea, France, the UK, the Netherlands, Bulgaria, India, Indonesia, Russia, Spain, Turkey, New Zealand and Portugal.

Fostering a sense of community in this group which crossed cultural and language barriers, was a challenge, says Rob Harwood, Shell’s construction manager for Prelude.

“We had to find a way to unite everyone and get them on the same page, especially when it came to safety,” he says.

One way of achieving this was to request that everyone wore a safety card with their staff identification tags. Each card also had a photo of the person’s family, and a pledge to stay safe for them.

For YG Kang, SHI’s Prelude project director, the experience of constructing Prelude has left a lasting mark. “We have learned many new things and we have made many new friends,” he says.

By Soh Chin Ong and Ryan Harrison

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