After a traumatic accident during childhood play when he was thrown into water and injured his foot, which left him with a lifelong limp, Fernez became fascinated with creating a device which would enable a swimmer to stay under water for a few minutes to help save drowning people.
During the summer of 1912 Fernez tested his equipment by diving 6 metres deep in the river Seine near Alfortville and remaining immersed for 58 minutes, only being forced to the surface by the cold of the water.