Guêpe-class submarine

The Guêpe-class submarines, designed by Emmanuel Petithomme and built under French Minister of Marine Camille Pelletan's ministry, were solely intended for use in harbor defense.[1][2] Although ten were projected, only two of the class were laid down in Cherbourg.[2][3] Neither of these were completed before Camille Pelletan was replaced as Minister of Marine and his successor cancelled their construction.[2][4] The class-name, "guêpe", is French for wasp.

With a single-hull design, the Guêpe-class submarines were planned to have a surfaced displacement of 44 tons,[1] and were 20.5 metres (67 ft 3 in) in length, with a beam of 2.1 metres (6 ft 11 in).[2][5] If built, the Guêpe submarines would have been powered by one Schneider diesel engine driving a single shaft, which would have provided a top speed of 10.5 knots (19.4 km/h; 12.1 mph) when surfaced and 9 knots (17 km/h; 10 mph) when submerged. Each vessel would have had a range of 128 nautical miles (237 km; 147 mi) at 10.5 knots (19.4 km/h; 12.1 mph), while surfaced, and 80 nmi (150 km; 92 mi) at 6 knots (11 km/h; 6.9 mph) when submerged, and had a crew of seven. Guêpe-class submarines had a maximum depth of 20 m (65 ft 7 in).[5] The vessels' armament would have consisted solely of two 450 mm (17.7 in) Drzewiecki drop collar torpedo launchers.[5]

Ordered in 1904, Guêpe 1 and Guêpe 2 were laid down in 1906 at the Cherbourg Naval Base.[2][3] Eight more boats, Guêpe 3 to 10, were planned to be built in Cherbourg, Rochefort, and Brest.[5] Only the first two submarines were ordered on 8 October 1904 and laid down. Construction stopped in March 1908.[5] The pennant numbers Q 51 to 58, reserved for Guêpe 3 to Guêpe 10, were assigned the following year to Pluviôse-class submarines.[5]