A cut to the Australia Singapore Cable (ASC) has been repaired in record time, with services restored in just 13 days—a process which would normally take months.

The ASC is a fibre cable system with a capacity up to 60 terabits per second (Tbps), stretching 4,600 kilometres between Perth and Singapore, with connections to Christmas Island and Indonesia.

On Sunday 1 August 2021, the cable was cut off the coast of Perth after a container ship allegedly dropped its anchor in a cable protection zone. The break impacted services passing into and out of Perth, while services between Christmas Island, Jakarta and Singapore remained operational.

Vocus’ Operations Command Centre, field technicians, and submarine cable maintenance partners were immediately deployed to the Perth cable landing station, where optical testing confirmed a break to the cable approximately 10 kilometres off Perth’s coast, at a water depth of 27 metres.

Vocus IP services and traffic were immediately re-routed where possible, and remained operational as traffic destined for Asia was temporarily routed through Australia’s east coast via Hong Kong and the United States. Our engineers worked tirelessly through the night and successfully optimised traffic out of Perth to Singapore via an alternate cable system.

We also quickly engaged with our marine repair partner, SubCom. Its repair vessel the CS Reliance was located nearby off the coast of Perth, allowing it to be rapidly re-deployed to commence repairs to the ASC.

After obtaining all the required permits and approvals, the CS Reliance began repairs on Thursday 5 August—just four days after the break occurred. It was an all-hands-on-deck effort as the team worked around the clock to repair the ASC. Scuba divers and a remotely operated vehicle were deployed to identify both ends of the cable break, with the faulty segment (which was several kilometres long) then removed from the water.

By Monday 9 August, just four days after commencing repairs, the south side of the break had been spliced, while a section of new cable was laid toward the north end of the break. Bad weather in the region slowed repairs as the CS Reliance temporarily anchored for the safety of the crew, with repairs recommencing on Wednesday 11 August.

The final splice reconnecting the north and south ends of the cut section occurred on board the CS Reliance in the early hours of the morning on Friday 13 August. Vocus commenced testing of the cable soon after, and normal services were restored as of 13:36 AEST on 13 August.

From the time the cable was cut on Sunday 1 August to the resumption of normal services, Vocus staff and the crew of the CS Reliance worked 24x7 and through turbulent weather to complete the repairs. Because the CS Reliance was already in the area, repairs were conducted in record time—a major effort that normally would take months was completed in just 13 days.

Vocus would like to thank our customers for their patience during the outage, and also offer our thanks to Vocus team, and the team on board the CS Reliance, for their incredible efforts to restore services in record time.