The Shallow End

On Christmas Day 2024, an oil tanker called Eagle S sailed west from a Russian port on the Baltic Sea. One of its anchors was down, dragging along the bottom. Finnish prosecutors say the ship dragged it for about 56 miles over six hours, damaging a power cable between Finland and Estonia and four internet cables.

When authorities called the ship that afternoon, two officers said both anchors were up and secured, according to the charges. The first officer's defense later said the answer was given in good faith; the anchor's fall could not be seen from the bridge. When the crew finally hauled in the chain, the anchor came loose and stayed on the seabed, the charges say.

For businesses that depend on these connections, the cause can remain uncertain long after service is restored. Near shore, undersea cables are vulnerable to shipping accidents, and deliberate damage can be difficult to distinguish from an accident.

Fiber-optic cables carry emails, video calls and stock trades across oceans as pulses of light through glass fibers. Telecom companies have long shared ownership of cables or sold their capacity. Google, Microsoft and Amazon now invest in them too.

Amazon is involved through Amazon Web Services, its cloud computing business. The cables connect the network that delivers customers' software and data across continents. Google uses its cables to support services including Gmail and Google Cloud.

Companies can pay to use another operator's cable or help finance a new one. At the scale of Google or Amazon, investing in the cable can cost less over time. It also gives them more say in where it connects and how much data it can carry.

The cables follow the seafloor from coast to coast. On one charted route from Long Island to France, the cable lies more than a mile down for 94 percent of its length, by our calculation.

Near France it climbs the continental slope and crosses the continental shelf, the shallow underwater edge of the continent. Every ocean-crossing cable eventually enters shallow water to reach land, bringing it within reach of anchors and fishing gear.

In one manufacturer's cable family, the deep-ocean version is about two-thirds of an inch across. Steel wires strengthen the cable, while copper carries electricity to power signal boosters along it.

Near shore, extra steel armor makes the cable about 1.4 inches across, and crews usually bury it for protection. In deep water, beyond the reach of anchors and fishing gear, the cable can lie on the seafloor with much less protection.

An anchor holds a ship in place by digging into the seabed. The one Eagle S lost was recovered in January 2025. The recovered anchor, shown in photographs released by the authorities, was about 13 feet long and weighed about 12 US tons.

Burial helps, but a heavy anchor can dig deeper. A 2009 industry and UN report describes a roughly 9,000-pound anchor penetrating about 16 feet into soft seabed, below the two feet or more at which many cables are buried. If an arm catches the cable, the moving ship can pull it until it snaps.

The Baltic averages about 170 feet deep. Another cargo ship involved in a cable break, Yi Peng 3, carried about 1,080 feet of anchor chain. Over the deep Atlantic, that same chain would end thousands of feet above the bottom.

Eagle S flew the Cook Islands flag. Estonia's security service identifies it as part of Russia's shadow fleet, the tankers used to keep Russian oil exports moving despite Western sanctions. That connection is not proof of an order to cut cables. The charges allege neglected duties and knowledge of faulty anchor gear; they do not allege an intention to damage the cables.

In a separate incident in January 2025, the cargo ship Vezhen damaged another cable. Swedish investigators found that two anchor restraints had failed and a wave broke the third. The autopilot compensated for the drag, and no alarm reached the bridge. The prosecutor concluded it was an accident.

For Yi Peng 3, Swedish investigators could not rule out either an accident or a deliberate act. They boarded more than a month after the damage, by which time the voyage recorder had recorded over the trip.

Specialized submarines can reach cables beyond anchor depth. In April 2026, Britain disclosed that it had tracked Russian submarines in the North Atlantic for more than a month. It said the specialist vessels were built to survey infrastructure and sabotage it in conflict, but reported no evidence of damage. Russia has denied targeting cables.

This is a vulnerability in the confrontation between Russia and NATO. Gray-zone warfare uses disruption and coercion while avoiding an open military clash. A state could exploit ordinary shipping to damage a cable, then dispute whether anything deliberate happened. Proving who ordered it could be harder still.

Restoring the physical connection takes longer than rerouting the data. A repair ship must reach the site, recover the ends and join them to spare cable aboard, then lower the repaired section. Each joint can take a day or more. One Finland–Germany cable damaged in November 2024 was restored about 11 days later.

A broken cable does not necessarily mean an outage. Finland's telecom regulator said traffic on the damaged data cables was immediately switched to backup connections, though users might notice some slowness.

Amazon's planned Maryland–Ireland cable, due in 2028, shows what businesses can do. Its landing points avoid traditional cable corridors, giving AWS another path if other routes fail. Governments are spending on protection too: NATO began Baltic patrols in January 2025 using ships, aircraft and naval drones.

For investors, the exposure reaches beyond cable owners to the businesses relying on their service. Repeated damage could use up spare routes faster than crews can restore them. Extra routes and protection cost money, even when no attack is proven. Businesses have to keep their connections working while the argument over responsibility is still going on.

Anthony

The Luniter Observatory

Disclosure: I own shares of Alphabet (GOOG), Microsoft (MSFT) and Amazon (AMZN).

Research and educational analysis only — not financial advice. Every investment carries risk.