Abstract: The present invention concerns a convertible the capable of being transformed to change from a conventional mode of propulsion to a nuclear mode of propulsion. The submarine includes an aft section delimited by a pressure tight hull and two transverse bulkheads in which are located electric energy production and storage installations using batteries and diesel-generators. The aft section can be transformed to convert the submarine to the use of an anaerobic energy source by substituting for these installations, installations adapted to the anaerobic source of energy while preserving the integrity of the pressure tight hull and bulkheads, without internal substitution causing any substantial modification in the weight or centering of the aft section.