Circé-class submarine (1907)

The Circé-class submarines consisted of a pair of submarines built for the French Navy (Marine Nationale) during the first decade of the 20th century. One boat was sunk in a collision before the First World War and the other was torpedoed and sunk by a German submarine in the last year of the war.

Design and description
The Circé class were built as part of the French Navy's 1904 building program to a double-hull design by Maxime Laubeuf. The submarines displaced 361 t surfaced and 498 t submerged. They had an overall length of 47.13 m, a beam of 4.9 m, and a draft of 3.24 m. Their crew numbered 2 officers and 20 enlisted men.

For surface running, the boats were powered by two German MAN 315 PS diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 180 PS electric motor. During their sea trials in 1908, they reached maximum speeds of 11.9 kn on the surface and 7.3 - 7.7 kn underwater. The Circé class had a surface endurance of 2000 nmi at 7.3 kn and a submerged endurance of 76 nmi at 4 kn.

The boats were armed with six external 450 mm torpedo launchers; four of these were fixed outwards at an angle of five degrees, two firing forward and two firing to the rear. The aft tubes were reversed in March 1911 so they too fired forward. The other launchers were a rotating pair of Drzewiecki drop collars in a single mount positioned on top of the hull at the stern. They could traverse 150 degrees to each side of the boat. A support for a 37 mm deck gun was ordered to be installed on 29 March 1911, but the gun itself was never fitted.