A severed undersea cable, a ship that switched off its transponder, and a case that may never close

Two undersea data cables were severed nine hours apart along a forty-kilometre stretch of seabed. A survey vessel has since photographed a continuous drag mark crossing both cable routes, consistent with an anchor being dragged along the bottom.

Vessel tracking data reviewed by investigators shows a single ship whose transponder stopped broadcasting for eleven hours, resuming after it had cleared the second location. Transponders switch off for many reasons, including equipment failure, and switching one off is not by itself evidence of anything.

The jurisdiction problem

The cuts occurred outside territorial waters. The ship is registered in one country, owned through a holding company in a second, chartered by a firm in a third and crewed by nationals of four more. Under the law of the sea, the flag state has primary responsibility for investigating conduct by its vessels — and the flag state has not opened an inquiry.

Prosecutors in two of the affected countries have opened files anyway, on theories that reach conduct causing damage to their infrastructure. Neither expects to obtain custody of the vessel or its crew.

We can establish what happened to a high standard. Establishing who is answerable for it is a different problem with a much worse success rate.— A prosecutor with one of the national investigations

Repairs and capacity

A repair vessel is on site. Splicing a deep-water cable is slow work — locate, grapple, lift, cut out the damaged section, splice, test, lower — and operators expect about three weeks per cable.

Traffic has been rerouted over remaining paths. Capacity is sufficient, but latency on affected routes has risen by between eight and twenty milliseconds, enough to be noticed by financial systems and by anyone playing a game against a server on the other side of the break.

• Cables cut: two, nine hours apart across a 40 km stretch
• Evidence: continuous seabed drag mark; one vessel dark for eleven hours
• Jurisdiction: flag state has not opened an inquiry; two others have
• Repairs: about three weeks per cable; latency up 8–20 ms on rerouted paths

Cable operators have been pressing for years for a faster route to protective orders and for mandatory anchor-monitoring in designated corridors. Both proposals require agreement among states that have so far preferred to handle each incident individually.