01 / MOULIN À VENT
THE FULL-SCALE PROTOTYPE
Moulin à Vent was an existing catamaran adapted into the full-scale Turbosail test platform. The 1985 technical paper documents the Cousteau–Pechiney program moving from theoretical and wind-tunnel development toward an experimental installation operating at meaningful marine scale.
Trials at Étang de Berre near Marseille, subsequent Mediterranean operation and the 1983 Atlantic experiment exposed the system to vessel motion, variable winds, structural loads and working conditions that laboratory research could not fully reproduce. The vessel itself—its engines, controls, hull and Turbosail installation—functioned as part of the experiment.
EXPLORE THE TURBOSAIL →02 / THE LESSONS
VALIDATION + LIMITS
The Moulin à Vent program produced full-scale performance information while exposing control, structural and operational questions that wind-tunnel testing could not completely reproduce. Sustained marine operation challenged the concept through changing conditions and generated practical experience for the next stage of development.
The surviving sources support continuity between the prototype program and Alcyone, but they do not establish that every later design feature resulted from one specific event or failure aboard Moulin à Vent. The 1983 passage was not the end of the Turbosail concept; it marked the transition from prototype testing toward a vessel conceived around the system.
MOULIN À VENT
Prototype platformExisting catamaran adapted for testingSingle experimental Turbosail installationMediterranean + Atlantic trialsPurpose: prove and challenge the concept at full scaleALCYONE
Purpose-built expedition vesselDesigned around the evolved systemTwin TurbosailsWorldwide expedition servicePurpose: integrate the technology into sustained vessel operations03 / ALCYONE
THE EXPERIMENT BECOMES A SHIP
Moulin à Vent was adapted to test the concept. Alcyone entered service in 1985 as a purpose-built expedition vessel incorporating the evolved system into normal operation through twin Turbosails working in combination with engine propulsion.
The surviving Cousteau vessel record describes Alcyone's worldwide research, exploration and filmmaking service and reports approximately one-third fuel savings from the combined propulsion arrangement. That figure is presented here as the vessel record's claim, not as an independently verified measurement.
Bureau Mauric's later retrospective traces the development from the Moulin à Vent prototype to Alcyone while providing the perspective of later operational experience.
04 / WHY IT MATTERS
A MISSING LINK IN THE STORY
Alcyone is the better-known operational expression of the Turbosail. Moulin à Vent preserves the experimental stage that came before it: the point where an existing vessel carried the concept out of controlled research and into full-scale marine testing.
Preserving the prototype preserves evidence of the difficult middle of innovation—concept, experiment, lessons and then operational vessel. That history complements Alcyone rather than competing with it: one vessel records the experiment, while the other records its evolved application in expedition service.