As a four‑ship multinational task group conducted a replenishment at sea (RAS), the surface was alive with coordinated movement.

Below the waterline, one department bore the responsibility of keeping calm amid the chaos.

For the stokers, if a RAS isn’t done right, or the fuel received isn’t up to scratch, it can be an environmental disaster.

On her regional presence deployment navigating the South China Sea, HMAS Toowoomba recently sailed in company with Royal Canadian Navy frigate HMCS Charlottetown, and United States Navy dock landing ship USS Ashland.

Canadian Oiler MV Asterix provided support to the task group.

Toowoomba’s assistant marine engineering officer, Lieutenant James Scotson, said the support was as seamless as refuelling from a Royal Australian Navy vessel.

“With our partners, RAS is universal. We have a set procedure, we know what to expect and it’s hard to stray from that; everything is the same,” Lieutenant Scotson said.

Completing a RAS requires all hands-on deck. Outside, three-connected ships travel at 12 knots (almost 30 kilometres per hour), just 50 metres apart, while transferring up to tens of thousands of litres of aviation and diesel fuel to each vessel.

'During a RAS we will also take up to 10 samples until we know it’s safe to burn, or if we have to take further steps to ensure it can be used.'

Inside Toowoomba the Marine Engineering Department runs the machinery control room like a mission control centre, ensuring the resupply of the vessel at sea.

Senior diesel technician Leading Seaman Paul Richards said fuel quality security was a never-ending process, to ensure the sustainability of the ship.

“Before receiving fuel, we will be given a fuel condition statement; we will then be provided with a sample,” Leading Seaman Richards said.

“During a RAS we will also take up to 10 samples until we know it’s safe to burn, or if we have to take further steps to ensure it can be used.”

All fuel received during a RAS is quarantined in its own tank, until safe for release into the ship’s fuel service system. Testing the supply is constant throughout a deployment, only pumped through to the engines when stokers are satisfied it is safe to use.

“The fuel quality control is to keep everything in storage, and we continually monitor those storage tanks,” Leading Seaman Richards said.

The ever-vigilant marine engineers know that keeping a ship running is essential, which is why fuel security is often the most overlooked, yet vital, component of any ship at sea.

“If a storage tank becomes contaminated, we will need to quarantine that tank and potentially lose it. This could reduce our capability and length of time at sea,” Leading Seaman Richards said.

Fortunately, thanks to the interoperability, skill and professionalism of the Royal Australian, Royal Canadian and United States navies working as a joint force, they are able to sustain themselves during operations in the South China Sea.