Guépard

History

Guépard was the lead ship of her class of destroyers (contre-torpilleur) built for the French Navy during the 1920s.

Design

Three years after the Jaguar-class, the Marine Nationale came back to the contre-torpilleur-types with a revised design. Key in the design points was improving over the initial class, in particular an improved main battery using a 138.6mm gun. As a result, displacement increased substantially, to 2,690 tonnes (3,220 tonnes at full load), requiring machinery power to increase once more – this time to 64,000 shp – to maintain a design speed of 35.5 knots.

Despite the increased power of the machinery, the Guépard-class used only four boilers (reducing weight considerably), made possible by newer and improved types working at a pressure of 20 kg/cm²/215°C. Additionally, lessons from cruiser construction were applied, with the machinery adopting a ‘unit’ arrangement – previously, all turbines were aft of the boiler rooms, which made it possible for the ship to be immobilized by a single hit. A unit arrangement alternated placement – a boiler room, then turbine room, followed by a boiler room, and another turbine room. Thus, no one hit could completely disable the ship, and one shaft would always (in theory) be operational.

The main armament adopted a considerably more powerful gun – the 138.6mm/40 Mle 1923. The gun fired a 39.9 kg SAP shell at a velocity of 700 m/s, allowing for a maximum ballistic range at +35° elevation of 18,200 meters. However, like the 130/40, effective range was lesser, only 12-13 km (especially with the early 3-meter rangefinders, which could not spot fall of shot over 13 km). Rate of fire on the guns was a little higher – 5-6 rpm – although still less than designed, as the gun rammers were too weak and the shells too large to be effectively handled by gun crew. The amidships gun benefited with a much larger ready rack, of 48 shells. Fire control arrangements were largely the same, although unlike earlier ships the Mle 1923B fire control computer was installed when the ships were built, not after. Anti-aircraft armament was also altered - the 75mm guns were disposed of and replaced by four 37mm/50 Mle 1925 semi-automatic cannons, designed to be similar to the Vickers 40mm pom-pom used by the British and Italian navies (the latter produced by Terni under license). The guns were relatively ineffective, due to a horrendously slow rate of fire for the caliber (15-21 rpm, versus 50-75 rpm on the 40mm pom-pom). These were backed up by two twin 8mm machine gun mounts, eventually replaced by 13.2mm machine guns.

Torpedo armament was more capable than the prior types – although it still used two triple banks, it used an improved 550mm Mle 1924T launcher, which was capable of using the new 550mm Mle 1923DT torpedo. Warhead power was increased considerably, as was range – now 9,000 meters at 39 knots. Fire control methods remained the same as previous classes.

Overall, the ships were a considerable improvement over the Jaguar-class. Although they still had stability issues, they were far more stable than their troubled predecessors. They exceeded their design speeds in trials, and were much faster in service than their predecessors. However, like both the prior destroyer classes, turbine machinery was still not particularly reliable, and fuel consumption was much greater than predicted, reducing operational utility.

Service

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  Guépard at anchor