In May 1935, the French Navy issued a specification for a long-range flying boat to replace the obsolete Breguet 521. To meet this requirement, Latécoère designed the Latécoère 611. This was a cantilever monoplane powered by four Gnome-Rhone 14N radial engines and fitted with a twin tail. It was also fitted with stabilising floats that retracted into the outer engine nacelles. The prototype was assembled at Biscarrosse, and first flew on 8 March 1939.[1]
Although it was intended that the aircraft be armed with a 25 mm cannon in a dorsal turret, this was unavailable, and was replaced by one carrying two 7.5 mm Darne machine guns, with a further four machine guns firing through portholes and two in a retractable tail position. In December 1939 the French Navy placed an order for twelve of a modified version, the Latécoère 612, which was to be powered by four Pratt & Whitney R-1830 radial engines. These aircraft, however, were never delivered.
The prototype Latécoère 611 was delivered to the French Navy on 12 April 1940[1] and named Achenar, being flown to North Africa in June 1940 and subsequently disarmed under the terms of the Armistice. After being damaged in a collision with another flying boat, it eventually entered full service with the Vichy French Navy on 15 October 1941, operating with Escadrille 4E at Port Lyautey and Dakar.[1]
In November 1942, following the Allied Invasion of North Africa, Escadrille 4E switched sides and joined the Free French, carrying out anti-submarine patrols over the South Atlantic, later (October 1943) being enlarged to form Flotille 7F, which continued to fly the Latécoère 611 alongside Short Sunderlands. The Latécoère was re-armed in 1944, with the dorsal turret being fitted with two 50 cal. Browning machine guns and a similar gun being fitted in the tail.[1]
The sole Latécoère 611 was finally retired from service as a transport in 1947.[2]