Work on the Upstream Gate of the Joubert Sluice Dock in Saint Nazaire

The replacement of the upstream gate of the Joubert sluice dock is intended to enhance the structure’s reliability, to extend its service life and to improve the level of service provided for maritime and land-based activities. This new gate will also open up new development opportunities for stakeholders in the sector. This major work project will begin in the spring of 2026 and will be completed in early 2029.

Traffic around the Joubert Sluice Dock and Progress of the Work

piste cyclable sont réalisés sur les avenues de la Prise d'eau et de Chatonay

Traffic : Work on Constructing a New Cycle Path

Since 3rd March, work has been underway to construct a cycle path along Avenue de la Prise d'Eau and Avenue de Chatonay at the Port of Saint Nazaire, between Gate 17 of the Chantiers de l’Atlantique Shipyard and the Joubert sluice dock.

The construction project will involve roadworks throughout the period from March to September 2026.

To ensure the safety of all concerned, including pedestrians, cyclists and motorists, we ask that you remain vigilant and observe the temporary road signs, traffic directions and speed limits in place within the area of the roadworks.

Some of the work will be carried out at night so as to minimize the impact on traffic.

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Work Project: Assembly of the New Gate in Dry Dock N° 3

Between March 2025 and April 2026, dry dock N° 3 at the Port of Saint Nazaire will be used for the assembly of the 34 sections that will form the future upstream gate. These sections are to be prefabricated by MATIERE at three factories (two in France and one in Belgium), representing a total of nearly 50 000 hours of preparatory work.

The assembly operations in dry dock N° 3 will take a year, and will include welding work and the application of anti-corrosion coatings. Between 30 and 50 people will be involved in carrying out this crucial phase of the project.

Once the assembly work has been completed, the new gate will be set afloat in the dock, then conveyed to the Joubert sluice dock, where it will remain until it takes the place of the existing structure.

key milestones

SPECIFICATIONS OF THE JOUBERT SLUICE DOCK

At the Port of Saint Nazaire, construction work on the Joubert sluice dock began in 1930, coinciding with the building of the cruise liner Normandie. The work was completed in 1934, and the structure was named in honour of Louis Joubert, then President of the Chamber of Commerce and Industry. The sluice dock suffered severe damage in March 1942 during Operation Chariot, when the destroyer Campbeltown collided with its downstream gate.

Serving both as an access lock to the Penhoët dock basin and as a dry dock for taking vessels out of the water, the sluice dock’s dimensions are remarkable: it measures 350 metres in length, 50 metres in width and 17 metres in depth. It is closed by two "barrow-type" rolling gates, which were rebuilt after the war. These gates move horizontally along rails to open or close the lock, then slide into their recesses once open. An entirely new gate replaced the downstream gate on the River Loire side in 2012.

The upstream gate, which was installed back in 1947, is now in such a state of disrepair that it must be replaced.

A Strategic Structure Right in the Heart of the Port of Saint Nazaire

A strategic piece of infrastructure for both military and civilian activities, the Joubert sluice dock plays a central role in Saint Nazaire’s maritime and port ecosystem. Its exceptional dimensions enable it to accommodate not only French Navy vessels but also cruise ships under construction at the Chantiers de l’Atlantique Shipyard, as well as projects for offshore wind farms along France’s Atlantic Seaboard. Ensuring its smooth operation is essential for the local economy and the Region Community’s industrial sectors.

FINANCING

This investment operation was approved by the Supervisory Board of Nantes ‒Saint Nazaire Port in November 2024, involving a substantial expenditure in the amount of 40 million euros.