The teams at the Naval Group's Nantes-Indret site are at the origin of a world premiere: their propeller is a technological feat and a source of pride for the military naval sector.

An XXL propulsion propeller

With its 2.5 meters (8.2 feet) of wingspan supported by five blades of 200 kg (441 lbs) each, the 1.5 ton (1.47 imperial ton) apparatus left the workshops of the Naval Group site in Nantes-Indret in October 2020 to reach the site of Brest and be mounted on the propeller shaft. The assembly was transferred to the basin dedicated to the maintenance of the tripartite minesweepers to be mounted on the National Navy minesweeper, the Andromeda, in November 2020. The sea trials then took place in late December and were successful.

World premiere

Three years of research and development, conducted by the technical and Innovation department in conjunction with the Ecole Centrale Nantes as part of the LabCom Joint Laboratory of Maritime Technology, were necessary to qualify the metal additive manufacturing process. The technique consists of depositing layers of material (metal wires) in order to make a piece instead of cutting that piece, from a block of material. This is the first time that a 3D printing part will serve a ship in all its operational activities.

Demanding specifications

The severe operating conditions of the ships justify meeting strong requirements (corrosion, fatigue, impact resistance...). Naval Group has partnered with Bureau Veritas throughout its process to present its supporting technical file in order to allow the Fleet Support Service (SSF) and the DGA (Directorate General of armament) to authorize the installation of the blades produced, on a military ship under normal operating conditions. The Blades received a certification from Bureau Veritas.

Promise for the future

For Eric Balufin, director of the Naval Group site in Brest, "The assembly of this propeller made via additive manufacturing is a great promise for the future." This new technology will allow us to significantly reduce technical constraints and therefore propose new solutions for the manufacture of components of complex geometry unachievable by conventional processes. It will also reduce production times to facilitate operations to maintain operational readiness.

And this is only a first step. Additive manufacturing increases acoustic discretion, efficiency (stealth and lightness) and productivity. Arguments that weigh heavily in rethinking the design of other complex pieces. After Aeronautics and the space industry, military shipbuilding enters the era of 3D.

© Naval Group

SMARTAPPART, the housing solution in Saint-Nazaire

The SMARTAPPART residential hotel is an economical alternative to hotels in the city of Saint-Nazaire. Rates are discounted starting from two nights. Its furnished and connected apartments are suitable for any type of stay, business trip or family getaway. Emergency health measures have been taken to secure facilities and minimize contact. With its innovative concept of online booking and payment and its minimal staff, SMARTAPPART makes every effort to guarantee your autonomy and the tranquility of your stay. 

Related reading:

A fundraiser is launched to restore the submarine L'espadon de Saint-Nazaire

The sail of the future is invented on the Saint-Nazaire Atlantic shipyards