A Month Under the Sea: Divers Lived in a Hyperbaric Chamber for Genoa’s Breakwater

Eight hours a day on the seabed for 28 consecutive days, inside a hyperbaric chamber. The mission of the divers who carried out the ordnance clearance operations necessary to begin construction on Genoa’s new Breakwater resembles a journey into space.

Today, with the work in an advanced stage and eight enormous caissons already placed in the sea forming the outline of the future breakwater, the feat of the diving teams stands as one of the extraordinary stories surrounding the creation of this ambitious and complex infrastructure project—among the most advanced of its kind in the world.

The seabed where the caissons are laid reaches depths of 50 meters, making it one of the deepest sites for a breakwater in Europe. Working at such depths with traditional techniques would have allowed only very short work intervals, as divers would need to decompress before surfacing—the deeper the dive, the shorter the allowed working time.

For this reason, the team adopted the technique of saturation diving in a hyperbaric environment—a highly sophisticated method used only in extreme conditions, such as open sea interventions on offshore wells. The ordnance clearance for the new Genoa Breakwater was entrusted to Drafinsub, a Genoa-based pioneer in this field, operating under the coordination of the “Per Genova Breakwater” consortium, led by the Webuild Group, which is in charge of the overall infrastructure construction.

On the construction site of the Genoa Breakwater, the “space capsule” is actually a hyperbaric chamber—more precisely, a “hyperbaric apartment” built on a barge anchored offshore. Inside it, three diving teams, each composed of two expert divers, lived for 28 days. At their scheduled time, the first team descended 50 meters to the seabed inside a diving bell, which maintains the same pressure as the hyperbaric chamber.

Once at the lowest point of the seabed and before opening the hatch of the diving bell, one of the two divers puts on a helmet, checks communications and safety systems, and ensures the circulation of warm water in the suit to maintain body temperature. Only then does the diver exit to work on the seabed, while the second remains in the bell, ready to swap in and complete the scheduled eight-hour deep diving shift.

This scientific marvel is made possible thanks to the special technique of saturation diving. Inside the hyperbaric chamber, the divers are surrounded by a gas mixture made up of 97% helium and 3% oxygen. This is the same pressure environment as on the seabed, allowing them to live in the saturation system and work without decompression issues.

During breaks, divers live inside the hyperbaric “apartment,” where they eat, sleep, use the restroom, and enjoy moments of social interaction. All of this takes place under the constant supervision of specialized coordinators and doctors. After 25 days of work, the divers enter a dedicated decompression chamber where they remain for around three days before exiting and returning to open air.

Saturation diving is just one of the many examples of excellence at the construction site of Genoa’s New Breakwater. Building an infrastructure that spans 6,000 meters and lies 400 meters from the existing dam is an extremely complex task, requiring a wide range of interventions and specializations—all working toward a common goal.

By significantly expanding the turning basin, the New Breakwater will allow even the largest container ships — up to 400 meters long — to enter the Port of Genoa, Italy’s second largest port.

Moreover, this infrastructure project will support Genoa’s role as a natural entry point for goods destined for Europe, increasing its competitiveness against the Port of Rotterdam, currently the continent’s largest commercial port. It is a strategic project made possible by the excellence of the many companies contributing daily to the Breakwater construction site.