Google and Facebook lay thousands of miles of undersea cables to ferry internet around the world. Here's how they do it.
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Isobel Asher HamiltonSep 19, 2021, 15:05 IST
Specialised vessels like this one are used to lay thousands of miles of internet cable along the seafloor.Alcatel submarine networks
Google and Facebook are invested in dozens of subsea internet cable projects around the world.
Laying these cables takes months of preparation, and specialized vessels take them out to sea.
Once laid, the cables can ferry huge quantities of internet data around the globe.
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Google and Facebook have both laid thousands of miles of cables along the seafloor, stretching between continents, to carry internet around the world.
An undersea cable laying vessel sails past icebergs during a project to lay cable between Canada, Greenland, and Iceland.
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Often, the two tech giants invest in cable projects along with a consortium of other companies, although Google has five privately owned cable projects underway.
The landing buoy for Google's Curie undersea cable.
Google Cloud
In total, Google is invested in 19 cable projects around the world.
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Facebook is invested in two cables that are currently active. It is involved in five more cable projects currently under construction, a spokesman said.
Cable laying vessel Ile de Bréhat off the coast of Australia.
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Here's how the companies lay the cables along the bottom of the ocean.
The new Grace Hopper cable will join existing Google cables like Curie, pictured here.
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First, the companies have to plan the route they want the cable to take.
Jayne Stowell.
Google Cloud
Jayne Stowell, strategic negotiator for Global Infrastructure at Google, told Insider planning the route can take up to a year.
A Facebook spokesperson told Insider it conducts a bathymetric and geophysical survey along its expected route, which allows it to plan down to the meter.
Laying vessels Ile d'Aiz (in the foreground) and Ile de Batz (in the background).
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To do this, it sends out vessels equipped with sonar to map out the seabed and look for risks such as high currents, underwater landslides, and unexploded bombs or mines.
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The cable itself is about the thickness of a garden hose, Stowell said.
A subsea internet cable is loaded onto a laying vessel.
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Cables are wrapped in a copper casing for electricity conduction.
Subsea cables in the process of being manufactured.
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"A plastic and steel sheathing is then added to waterproof the cable and help it withstand potentially adverse ocean conditions such as heavy currents, earthquakes or interference from fishing trawlers," Stowell said.
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For Facebook's 2Africa cable, it's using aluminium rather than copper, which it said will lower manufacturing costs and enable longer cables.
A subsea cable before it's had its sheathing added.
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2Africa is in the process of being laid around the entire continent and is 37,000 kilometers long — only slightly shorter than the circumference of the Earth.
Once the route is mapped out and the cable is made, it's time to load the cable onto a specialised laying vessel.
Crew members spooling Google's Curie subsea cable into tanks inside the laying vessel.
Google Cloud
Google's Stowell said the company uses a fleet of 50 to 55 specialised laying vessels, with capacity for up to 100 crew members. Just loading the cable onto the ship can take four weeks, she said.
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Facebook said its vessels generally need a crew of 30 to 50 people.
A specialised subsea laying vessel.
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The vessel leaves port, spooling the cable behind it. Once it gets into deeper water, it deploys an underwater plow to dig a trench along the seabed into which it lays the cable.
Machinery on a subsea internet cable vessel.
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"The natural movement of wave action will then cover the cable once the ship moves on," Stowell said.
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"An ocean plough does not look too different from a plow a farmer might use in a field, except it is much larger - about the height of a two-story building," Stowell said.
A subsea laying vessel in the Greenland sea.
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The plow is only used at depths of 1,000 to 1,500 meters (3281 to 4921 feet), Stowell added.
"This is where it is needed to protect the cable from potential damage from other seabed users - most frequently bottom trawling fishing vessels or ships anchors that are put down at sea in a storm," Stowell said.
Subsea cables need to be buried to protect them trawler nets like this one.
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A cable is fairly safe in the deep seas and has no need for burial nor armoring, she added.
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For longer cables, Stowell said Google also installs a device called an amplifier every 100 meters (328 feet) to boost the signal and keep the data moving.
An amplifier is loaded onto a laying vessel.
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"Although fibre-optic cables are made of the purest glass, over long distances the intensity of a beam of light begins to weaken," she said.
Subsea cable amplifiers after being manufactured.
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Amplifiers help boost the light back to its original intensity.
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When the laying vessel reaches its final destination it isn't able to come close to shore.
Engineers land Google's Grace Hopper cable on the beach in Bude, UK.
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Buoys are used to float the cable at the surface and it is guided into position by divers, jet skis, and smaller boats.
A line of buoys helps float a subsea internet cable as it's landed on the shore.
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Finally, the cable is pulled up onto the beach to a ready-made trench, where it's connected to a beach manhole, a buried container where the undersea cable is hooked up to a terrestrial cable - which in turn connects to a cable station.
A machine helps land Google's Grace Hopper cable on the coast of the UK.
Google Cloud
These cables are able to channel a huge amount of data around every second.
Small boats guide Google's Grace Hopper to shore from its laying vessel in Bilbao, Spain.
Google Cloud
Stowell said Google's Grace Hopper cable — which was landed in the UK earlier this week — is set to funnel 340 terabytes of data per second, which would mean 17.5 million people could stream 4K videos at the same time.
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