Émeraude-class submarine (1906)

The Émeraude-class was a class of six submarines built for the French Navy prior to World War I. They were designed by Maxime Laubeuf and represented an evolution from his earlier Aigrette-class. Key improvements included a more powerful engine, increased surface speed, and an improved hull design intended to enhance stability and underwater performance.

The class comprised the Émeraude, Opale, Rubis, Saphir, Topaze, and Turquoise. They were commissioned between 1908 and 1910.

The Émeraude-class submarines displaced approximately 395 tons surfaced and 425 tons submerged. They were powered by two Sautter-Harlé diesel engines for surface running and electric motors for underwater propulsion. Their armament consisted of six 450mm torpedo tubes, with four located in the bow and two externally mounted in trainable mounts.

These submarines served primarily in the Mediterranean Sea during World War I, participating in patrols and convoy escort duties. Turquoise was lost in 1915 after running aground in the Dardanelles. The remaining vessels were largely obsolete by the 1930s and were withdrawn from service, with some being scrapped. Their service provided valuable operational experience that influenced subsequent French submarine designs.