Gâvres is a commune in the Morbihan department of Brittany in north-western France. French Navy Minister Hyde de Neuville chose this pl…Gâvres is a commune in the Morbihan department of Brittany in north-western France. French Navy Minister Hyde de Neuville chose this place as a military testing area in 1829 for heavy marine ordnance. The extensive experiments performed at sea have later provided part of the data upon which Hugoniot's theory is based.