Duguay-Trouin-class cruiser

The three Duguay-Trouin class light cruisers were built for France in the early 1920s.

The fate of these three ships after the French surrender illustrates the dichotomy within the French armed forces at the time: one ship was interned, then joined the Free French, another twice resisted Allied bombardment and was destroyed, and the third was disarmed at a French colonial port and subsequently sunk.

The ships

 * Duguay-Trouin (decommissioned 9 March 1952)
 * La Motte-Picquet (disarmed December 1941)
 * Primauguet (lost 8 November 1942)

Design
The design of this class was the result of a protracted process that had started in mid-1919, with the Italians as likely adversaries. A detailed design (Project 171) had been completed by the end of 1919, but there were significant reservations within the Navy and the Chief of the General Staff withdrew them in February 1920. While discussion continued, there were opportunities to compare with newly commissioned cruisers of other navies. The foreign designs were indeed superior, particularly armament.

At the end of 1920, after having examined copies of the plans for the U.S. Omaha class, four designs had been drafted. All four used hulls based on the Omahas, with eight newly designed 155 mm and four 75 mm anti-aircraft guns and twelve torpedo tubes. The differences lay in the combinations of power and protection.

Design C was selected and detailed work started. The new class would achieve 34 kn, using oil firing and single-reduction geared turbines, and have minimal protection; barely splinter-proof on the gun shields. The main armament would be a new breech-loading M1920 gun of 155 mm calibre, based on an army weapon, with a range of 26,100 metres. In action, this weapon proved to be slow to operate. The 75 mm anti-aircraft battery was of the M1922 type.

Orders were placed during 1922 on this basis, despite determined efforts to "improve" the design.

None of the ships had their light armour truly tested by equivalent adversaries: Primauguets destruction at Casablanca was at the hands of a greatly superior force. As intended, they were fast and economical, although with a limited range.

Modifications
After completion, single catapults were installed on the quarter-decks of each ship, initially with two Gourdou-Leseurre GL-812 HY flying-boats, later the GL-832. The Duguay-Trouin and Primauguet were subsequently equipped with a single Loire 130 in the 1930s.

In 1942, Primauguet had her anti-aircraft battery increased.

Once back with the Allies, Duguay-Trouin had her torpedo tubes and aircraft installations removed in 1943 and her AA weaponry was augmented in 1943 and again in 1944, when radar was also added.