The French Navy was also already working on another design, Plongeur, with a compressed air engine, which was launched in 1863.
Towards the end of his life, Dupuy de Lôme worked on a project for an electrical submarine, largely inspired from the experimental results of the submarine Plongeur.
He held the rank of captain when he presented together with Bourdelle his project for the submarine Plongeur in 1858, and when he created the plans in 1860, under the code name Q00.