The shipyards, the starting point of a value chain Brittany is characterized by a high density of construction sites, of varying sizes: - very small shipyards, with 0 to 10 employees, which work on boats of less than 12 m and individually; - intermediate shipyards, from 10 to 50 employees, who work on ships up to 35 m (e.g.: Gléhen); - large shipyards, for vessels from 20 to 120 m (e.g. Piriou or Socarenam); - major projects, with a structuring ripple effect on the industrial fabric regional and interregional (e.g. Naval Group, Chantiers de l'Atlantique in Saint-Nazaire). Often positioned as integrators or integrators, the sites appear as the conductors of construction and maintenance operations. They outsource however, for the majority of them, a significant part of these operations: services architecture, engineering and studies, purchases from suppliers, subcontracting, etc. contractual relationships that they establish with this network of partners are a trait characteristic of industrial organization: if the shipyards constitute the part visible from the value chain, and the most symbolic as the place where the ship is launched, a significant and growing part of added value today comes from manufacturing companies small and medium sizes, active in different markets.