Allseas

The offshore contractor that built and runs the deep-sea nodule collection system

PrivateFounded 1985Châtel-Saint-Denis

Allseas is a family-owned offshore contractor of roughly 4,000 people, founded in January 1985 and seated at Châtel-Saint-Denis in Switzerland, with its engineering in the Netherlands. It belongs on this site for one reason: it designed, built and operated the only fully integrated polymetallic nodule collection system to have worked in the Clarion-Clipperton Zone since the 1970s, and it owns the vessel that did it.

On May 11, 2026, The Metals Company and a wholly owned Allseas subsidiary signed a Contract for Development Work and Commercial Production, effective March 30, 2026, under which Allseas completes, commissions and then operates the first commercial nodule collection system. The rest of the business, which is most of it, is pipeline installation, heavy lift, platform decommissioning, offshore wind and nuclear work, and none of that appears here.

News and articles

Overview

• Founded in January 1985 by Edward Heerema, opening at Châtel-Saint-Denis in Switzerland and The Hague in the Netherlands. The engineering office is now at Delft.
• The seabed minerals work began with a strategic alliance signed with DeepGreen Metals, now The Metals Company, in 2019.
• In March 2020 it bought the ultra-deepwater drillship Vitoria 10000, 228 metres long and 42 metres wide with berths for 200, to convert into a nodule collection vessel. She became Hidden Gem.
• In January 2021 it contracted the Dutch subsea specialist Seatools for the complete electrical, hydraulic and control system of the collector, keeping the collection technology itself in house.
• In May 2022 the collector was pressure-tested in the Atlantic, driving more than 1 km at 2,500 metres.
• From September to November 2022 the whole system ran in the NORI-D block of the Clarion-Clipperton Zone, the first time a fully integrated collection system including a riser had been tested there since the 1970s. A team of 130 crew and engineers ran it.
• The company’s own figure for that pilot is 3,000 tonnes of nodules lifted from more than 4 km down. Its November 2022 release put the haul at an estimated 4,500 tonnes, and the lower figure is the one it has published since.
• Scientists on a separate monitoring vessel tracked sediment plumes and noise throughout, and that data went into NORI’s exploitation application to the International Seabed Authority.
• In June 2024 Greenpeace protested at both the Delft and Châtel-Saint-Denis offices. The company’s answer was that it believes nodule collection is less damaging than land-based nickel, copper and cobalt mining, and that if that turns out not to be so, it stops.
• In September 2026 it announced the purchase of a new fleet of Schilling Robotics hybrid-electric Heavy Duty remotely operated vehicles rated to 6,000 metres, which will gradually replace its existing fleet. It named deep-sea mineral collection among the markets they are meant to serve.

The collection system

What the 2022 pilot did

• The first collection run brought up more than 14 tonnes of nodules in one hour at 4,380 metres.
• Nodules travelled 4.3 km from the seabed to the surface in 12 minutes.
• Across the programme the collector drove more than 83 km over the seafloor.
• The system was built, fabricated and tested inside about two years from the start of construction.
• The company states 3,000 tonnes were collected and lifted. Its release at the close of the trials estimated 4,500 tonnes.
• At the time, Allseas and TMC put the intended commercial rate at 1.3 million wet tonnes a year and readiness at the fourth quarter of 2024. The 2026 contract sets 3.0 million wet tonnes and commissioning from the fourth quarter of 2027.

Ownership

Allseas is private and family-controlled. The chain is sworn to the United States Securities and Exchange Commission in the Schedule 13D it files as a shareholder of The Metals Company, most recently amended on July 7, 2026.

Listed exposure

There is no ticker for Allseas and no way to buy it. The exposure runs the other way: Allseas is the largest strategic shareholder in its own customer. On the July 7, 2026, filing, Allseas Group S.A. and Allseas Investments S.A. may be deemed to hold 66,502,501 TMC common shares, ~15.4% of the 433,221,138 shares TMC reported outstanding in its quarterly report of May 14, 2026. Counting Argentum Cedit Virtuti NV, the foundation and Mr Heerema, the figure is 67,502,501 shares, ~15.6%.

How the stake was built

Under the 2026 contract TMC reimburses Allseas’ eligible development costs, half as incurred and half deferred and repaid out of future commercial production volumes. The deferred half remains payable whether or not commercial production begins, so Allseas’ position in the project is part contractor and part investor.

SEC filing archive

Allseas files with the SEC only as a shareholder of The Metals Company. These are those filings, hosted here.