Dilandu

The "Thetis"-class cruisers were 142 meters long, 15,2 meters wide and with a draft of 5,2 meters (5,7 fully loaded). Their standard displacement was 5200 tons, maximum - 5780 tons. They resembled the traditional French Navy armored cruisers of "Ernest Renan" type.

They were armed with 138-mm/55 cannons, modele 1910, the same guns that were used as secondaries on French Navy dreadnoughts and superdreadnoughts. The intial design suggested the use of older, 45-caliber long guns, but eventually ships were re-designed to use newer guns.

Eight main guns were placed in four dual turrets, one on bow, one on stern, and two at the center, in echelon arrangement. All turrets were electrically-powered; the max elevation was 30 degrees, which gave guns the maximum range of 18000 meters (by using the heavy SAP shell).

The secondary armament was composed of eight quick-firing 47-mm Hotchkiss guns, placed on weather decks and in hull ports. Also the cruisers were armed with four 450-mm underwater torpedo tubes, five torpedoes per each.

The armored belt have a maximum thickness of 80 mm at upper edge and reduced to 40 mm at lower edge. At the ends, the belt thinned to 40 mm at upper edge and 20 mm at lower edge. The belt was 2,5 meters high, of which almost a meter was below the waterline. Horizontal protection was composed of 30 mm armored deck with 45 mm slopes. Turrets were protected by 100 mm plates, their barbettes were 65 mm. Conning tower was armored with 80 mm plates.

The powerplant differ from ship to ship. All have mixed, oil-coal boilers of different designs. "Thetis" have combined powerplant with two Rato turbines and VTE at central shaft; other cruisers have all-turbine arrangement, but their turbines were from different builders. They generally have around 25000 ihp, and speed around 26,2-27 knots. The coal & oil supply allowed 4500 nm of 10-knot steaming.

The "emergency naval program" of Amiral de Villard, adopted by French Navy in 1908, not only included large-scape shipyard reorganization and re-ordering of the last three "Danton"-class semi-dreadnoughts as "Mirabeau"-class dreadnoughts, but also the re-start of French cruiser shipbuilding. Three "petites croisières à turbine" - "small turbine cruisers" - were ordered in 1908, to act as scouts and counter-scouts for main battleline.

Contrary to usual light cruiser development of other countries (such as Britain and Germany), the French light cruisers weren't the up-armored & faster protected cruisers, but rather smaller & faster versions of armored cruisers. They retained complete armored belt and main artillery in armored turrets, as well as classic French "multi-funnel" outlook. The main difference was the smaller size (less than 7000 tons), and higher speed, made possible by the use of steam turbines instead of triple-expansion engines.

Three cruisers of initial order - "Thetis", "Atalante" and "Reine Blanche" - were comissioned in 1912-1913. The additional cruiser "Neptune" was ordered as part of "supplemental naval program" in 1912. Also, in 1913 Peru ordered one cruiser for their own navy; initially named "Peruvier", this "export" cruiser was requisitioned by French Navy when World War I started, and comissioned as "Ocean".

The five turbine cruisers served as backbone of French Navy scout & patrol forces in Atlantic and Mediterranean. After Italy joined the war on Central Powers side, all of them were concentrated in Mediterranean, to serve as forward scouting forces for the French Navy battleships. Two of them were lost during the war; the "Neptune" was irreparably damaged by torpedo from Italian submarine in late 1915, and "Reine Blanche" was sunk with almost all hands by the fire of Austria-Hungarian battleships in 1917. Three more cruisers generally of the same layout - "Friedland", "Montebello" and "Marengo" - were ordered in 1915 to compensate for anticipated war losses.

Of the surviving ships, "Thetis" and "Ocean" were considered to be too worn-out by the end of the war, and both were decomissioned early. "Montebello" was transferred to Peru in 1919, as part of compensation for requisitioned "Peruvier" (she was renamed "Peruvier II"). Only "Atalante", "Friedland" and "Marengo" continued to serve until early 1930s.