Naïade-class submarine

The Naïade-class submarines, sometimes referred to as the Perle class were a group of submarines built for the French Navy at the beginning of the 20th century. There were twenty vessels in this class, which was designed by Gaston Romazotti. The class introduced internal combustion engines into French submarine design. They remained in service until just prior to the outbreak of the First World War.

Design and description
The Naïades were designed by Gaston Romazotti, an early French submarine engineer and director of the Arsenal de Cherbourg. They were of a single-hull design, following most previous French submarine designs, but with dual propulsion. The hull was constructed of Roma-bronze, a copper alloy devised by Romazotti to resist corrosion and reduce interference with the boat's magnetic compass; it was also believed to offer more flexibility at depth. The Naïade design was based on the first French submarine, FRENCH SUBMARINE Gymnote. The submarines had a heavy lead keel for stability when submerged. The submarines had a surfaced displacement of 70.5 LT and 73.6 LT submerged. They were 23.7 m long with a beam of 2.2 m and draught of 2.6 m.

The underwater power for the single shaft was provided by a Société Éclairage Électrique electric motor rated at 95 shp, while on the surface a Panhard et Levassor benzol engine rated at 57 bhp was used, giving an improved performance on the surface. The submarines had a maximum speed of 5.98 kn submerged and 7.20 kn on the surface and a range of 30 nmi at 4.1 kn submerged and 200 nmi at 5.5 kn on the surface. The Naïade class were armed with two single 450 mm torpedoes located externally in Drzewiecki drop collars. These were the first French submarines to incorporate an internal-combustion engine into their design.

Assessment
The Naïades were smaller than Romazotti's previous FRENCH SUBMARINE Morse and Morse-class submarines, smaller in fact than any French submarine to that date except the pioneering Gymnote. However the Naïades had an adequate armament (two torpedoes, carried externally) and a good performance, with a better range than Romazotti's previous designs or the contemporary Farfadet-class submarine, though not as good as FRENCH SUBMARINE Narval and Sirène-class submarine. They were considered good surface boats, with good maneuverability but erratic when submerged.

Service history
The Naïades were ordered as part of the French Navy's 1900 building programme, and were constructed over the next five years at the naval dockyards at Toulon, Rochefort and Cherbourg. The entire class was assigned for service in the Mediterranean Sea apart from the three submarines constructed at Cherbourg which served in the English Channel.

By 1905, they had been reclassified as harbour defence boats. They remained in service until just prior to the outbreak of the First World War, but by then had been superseded by more modern designs and all were stricken by mid-1914. The wreck of Alose which was scuttled during an aerial bombing exercise in 1918, was discovered and raised in May 1975. The vessel is preserved as a museum piece at the headquarters of COMEX (the Compagnie Maritime d'Expertises) in Marseilles and was declared a French national historic site in 2008.