The $170-million-dollar project, owned by Vocus, will link Australia with Singapore and Indonesia.

Luke Mackinnon, head of Vocus International said the laying of the main cable would begin in February next year and continue throughout March.

"We will perform the final splice in April, enabling the commissioning to begin. That will take place in May and June, giving us a ready-for-service date soon after," he added.

On the other side of the English Channel, the company is finishing work on the repeaters at a factory in Greenwich in the UK. Once the cable and repeaters are ready, ASN will assemble them at the Calais site.

“Next month the components will be loaded on a ship and brought to Singapore. We expect it to arrive either in late December or early January. At this point we will offload a third of the cable and repeaters at Singapore. The Ile de Re cable laying ship will pick them up in January and start laying in February,” Mackinnon said.

The other two-thirds of the assembled cable is to be transferred from ship to ship in January near Christmas Island. From there, a second cable laying vessel, the Ile de Batz, will lay the cable as it travels south from Christmas Island to Perth. The Ile de Re will start in Singapore and head south to Christmas Island.

Mackinnon said two ships were being used because the two legs would use different cable-laying techniques. “From Singapore to Christmas Island the cable will be buried up to four metres below the seabed using a 40-tonne plough. This is far slower than the usual cable-laying technique; the ship can only move at a few hundred metres per hour”.

He said while it was unusual to bury a submarine cable, it was necessary in this instance because the ASC travelled through the Java Sea which is shallow and highly trafficked.

An earlier cable running through this area was frequently broken, mainly due to fishing boats cutting the cable, and this could take weeks to fix, Mackinnon pointed out.

He said there were issues getting permits for ship movements in the area and Indonesian maritime law requires contractors to use local crews.

"The situation is quite different on the ASC leg between Christmas Island and Perth. The southern cable section passes through a deep ocean. Here the cable is simply laid on the sea bed. The boat laying this section can move far quicker, covering kilometres in an hour."

Graphic: courtesy Vocus