 Cousteau was not satisfied with the length of time he could spend underwater with the Le Prieur apparatus so he improved it to extend underwater duration by adding a demand regulator, invented in 1942 by Émile Gagnan.In 1943 Cousteau tried out the first prototype Aqua-Lung which finally made extended underwater exploration possible.In 1946, Cousteau and Tailliez showed the film "Épaves" ("Shipwrecks") to Admiral Lemonnier, who gave them the responsibility of setting up the Groupement de Recherches Sous-marines (GRS) (Underwater Research Group) of the French Navy in Toulon.