There are more than 400 undersea telecommunications cables connecting the world. Every few days one of them is cut. In almost every case the damage is accidental or an act of nature. The most likely causes, in descending order are underwater earthquakes, rock slides, anchors and fishing boats.
A small international fleet of specialist repair vessels works to fix broken cables. They are distributed along the main cable routes. The ships patrol the seas so they can get to a break quickly. If a cable operator is lucky, they may be only a day or so away from a break.
Once there, the repair ships go to work fixing the break. It’s not necessarily a long or difficult job, but there is a limited number of specialist cable repair ships in the world. They operate like taxi cabs on a first-come-first-served basis. If a number of cables in a region are broken at the same time, the last cable operator to call in for help may wait for some time while other cables are fixed.
Vocus Head of International Luke Mackinnon says the Australia Singapore Cable (ASC) passes through some of the world’s more risky waters. "The Java Sea is located right on the ring-of-fire, a geologically active zone where the earth’s tectonic plates meet. There are active volcanoes, frequent earthquakes and rock slides.
Mackinnon says on top of that the area has typhoons. "It's not just nature that we're up against. The Java Sea is shallow and busy with shipping traffic. That means ship anchors and fishing nets often accidentally drag along the sea bed. And then there are the sand pirates. These are contractors who illegally scoop sand from the sea bed to order".
All in all there’s a lot of activity that could damage a submarine cable. The existing SEA-ME-WE3 cable covering the Perth to Singapore route through the Java Sea has had more than a normal share of disruptive breaks. It was cut three times during 2017.
To minimise the risk of damage to the ASC, the Java Sea stretch, which runs from Christmas Island to Singapore is buried in a trench up to four metres below the sea bed. That’s deep enough to avoid fishing nets and anchors and provides protection from most earthquake or rock fall damage. But that’s not all; a 10km stretch of the cable leading into Singapore Harbour is buried at a depth of 10 metres, using sophisticated underwater machinery, for maximum protection. The ASC also uses armouring on segments where the cable reaches across an underwater chasm.
"We're confident the design of the ASC mitigates many of the common risks that can cause problems in the area where the cable is located. This means less disruption for customers and maintained network performance for consumers, a win-win for everyone," says Mackinnon.