The Basslink Interconnector, the world's second-longest subsea cable providing energy and wholesale high-speed telecommunications services across fibre-optic assets to Tasmania, will be repaired by May after a six-month outage, the company has announced.
Basslink said it found the fault around 98km from the Tasmanian coast after collating over 500 hours' worth of images and data from 20 remote-operated vehicle dives. The company said it has conducted 24-hour fault location identification work on more than 30 days since December.
It is now able to proceed in repairs, the first stage of which involves cutting the cables. Further cable cutting may be required to narrow down the exact location of the fault due to its "complex nature" and "lack of visible damage", Basslink explained.
After cutting the cables, the ends will be brought onto the repairs ship, tested, and capped to prevent water leakage.
This process is expected to take around two weeks.
"While there remains some more days of work and analysis to be done before we can provide a more accurate estimate of return to service, it is an important milestone," said Basslink CEO Malcolm Eccles.
"We empathise with the community over the time that it has taken. However, the decision to cut the cables must be made with great care and consideration due to its complexities and challenges. The consequences of a hasty and ill-considered decision will be far-reaching. We have reached this milestone only after detailed analysis of the test results and close consultation with leading experts from around the world."
Once the cables are cut and capped, the ship will return to Geelong, Victoria, to pick up further equipment, spare cables, and specialised repair workers to take back to the fault location. New cables will be inserted where the cuts were made, with Basslink estimating the entire process to be complete by late May.
The Basslink outage affected repairs to telecommunications provider TPG's own submarine cable between Sydney and Guam, which experienced an outage in early February.
TPG's maintenance contract provides for relatively fast shipments based out of New Caledonia for hardware to repair any cable faults that arise; however, the maintenance ship was at the time already repairing the Basslink cable system fault.
"TPG Telecom has a maintenance agreement which provides the group access to the CS Ile De Re based in Noumea, New Caledonia. This ship is stocked with spare cables and other hardware for repairs to the cable system. We have been informed that the same ship is being used to repair the Basslink cable system," a TPG spokesperson told ZDNet last month.
"As a result of the Basslink repairs, extra delays can be expected and therefore TPG is currently considering other options for a faster repair using an alternative vessel. At this stage, TPG is not able to quote exact restoration times.
"Once TPG has a firm handle on the restoration times we will update our customers accordingly."
On February 17, TPG updated the issue on its website, saying it had sourced an alternative cable repair ship that had departed Taiwan for Cairns, Queensland, where it would be loaded with repair equipment on February 28.
The ship was due to arrive at the repair point on March 2, with TPG having previously said the repair would be complete by March 7. However, the fault is still listed as a current major outage on its website.
TPG did not respond to a request for comment on the status of its submarine cable repairs.