Massive undersea cable break — three repaired, one to go

Three of the subsea cables connecting Africa to the rest of the world have been repaired after they suffered breaks in mid-March 2024, with repairs still ongoing for one.

Repairs on the Africa Coast to Europe (ACE) cable were successfully completed on 17 April 2024, while work on two breaks on the West Africa Cable System (WACS) cable concluded on 30 April.

Repairs to the Sat-3 cable were completed in early April. This leaves just the Equinix-owned MainOne cable, for which repair work is estimated to conclude on 11 May.

Philippe Devaux, a well-known global submarine cable systems industry commentator, says the CS Sovereign cable laying ship has moved to the position of the fourth and last damaged cable after completing a second fault repair on the WACS cable.

This included replacing a repeater on the cable.

The four subsea telecommunications cables went offline around the same time on Thursday, 14 March 2024. The disruptions were discovered to have occurred off the coast of Cote d’Ivoire, near Abidjan.

Two vessels — Orange Marine’s Léon Thévenin and Global Marine’s CS Sovereign — were mobilised to repair the breaks.

ArcGIS projection showing cable repair progress. Credit: Philippe Devaux

The Léon Thévenin was destined for the site of the SAT-3 cable break, while the CS Sovereign was tasked with repairing the breaks on the ACE, MainOne, and WACS cables.

The companies and consortiums that own the cables have said a submarine landslide knocked them offline.

While the U.S. Geological Survey detected no earthquakes in the vicinity of the cable breaks at the time, this doesn’t rule out other possible activity on the seabed.

According to MainOne, the cable breaks occurred roughly 3km below sea level, making it highly unlikely that any human activity caused the disruption.

The cable breaks wreaked havoc with Internet connectivity in South Africa, resulting in a two-hour outage on Vodacom’s data network and taking down Microsoft’s locally hosted cloud services.

C.S. Sovereign, photograph by Ein Dahmer / Wikimedia Commons

The Microsoft outage prevented users from accessing their email, Teams meetings, and other Microsoft 365 services.

The Microsoft Azure region in South Africa was also offline for several hours, leading to knock-on effects for local companies that rely on these services.

Although repairs on the MainOne cable are still in progress, the WACS undersea cable is more important for most South African network service providers.

The MainOne cable connects West Africa and Europe, originating in Portugal, with African landing points in Cote d’Ivoire, Ghana, Nigeria, and Senegal. It has a capacity of 4.96Tbps

On the other hand, the WACS cable also originates in Portugal but has a landing point in South Africa in Yzerfontein, in the Western Cape. It has a capacity of 14.5Tbps.

WACS also has “express lanes” — including a dedicated fibre pair connecting South Africa directly to Europe — making it a critical resource for content delivery networks and South African network providers.