the concept. Design and construction At Euronaval 1998, France confirmed plans to build vessels based on the BIP-19 concept. Approval for construction of two ships, Mistral and Tonnerre, was received on 8 December 2000. A construction contract was published on 22 December and, after getting the public purchase authority's approval (Union des groupements d'achats publics, UGAP) on 13 July 2001, was awarded to DCN and Chantiers de l'Atlantique in late July. An engineering design team was established at Saint-Nazaire in September 2001 and, following consultation between DCA and the Délégation Générale pour l'Armement (General Delegation for Ordnance, DGA), began to adapt the BIP-19 design. In parallel, the concept was refined by DGA, DCN, the Chief of the Defence Staff and Chantiers de l'Atlantique. During the design validation process, a 1/120th scale model was built and tested in a wind tunnel, revealing that in strong crosswinds, the ship's height and elongated superstructures created turbulence along the flight deck. The design was altered to minimise the effects and provide better conditions for helicopter operations. The ships were constructed at various locations in two major and several minor components and united on completion. DCN, the head of construction and responsible for 60% of the value of construction and 55% of the work time, assembled the engines in Lorient, combat systems in Toulon, and the rear half of the ship, including the island superstructure, in Brest. STX Europe, a subsidiary of STX Shipbuilding of South Korea, constructed the forward halves of each ship in Saint-Nazaire, and was responsible for transporting them to DCN's Brest shipyard for final assembly. Other companies were involved in the construction: some work was outsourced to Gdańska Stocznia "Remontowa", while Thales supplied radars and communications systems. Each ship was predicted to take 34 months to complete, with design and construction for both costing 685 million Euros (approximately the same cost for a single ship based on or , and approximately the same cost as the preceding Foudre-class amphibious ships, which displaced half the tonnage of the Mistral class and took 46.5 months to complete). Starting from Dixmude, the rest of the French Mistrals and the two Russian Mistrals were built in Saint-Nazaire by STX France, which is jointly owned by STX Europe, Alstom and the French government, with STX Europe having a majority stake. DCNS will provide the combat system. The Russian ships' sterns were built in Saint Petersburg, Russia,