Hi again!
Georges-Leygues-Class destroyers
To replace the obsolescent T47- and T53/56-type destroyers in the ASW and the AAW role, a new common hull type was designed. As the Tourville-design was considered thoroughly satisfactory, the new ship was to retain as many of her features as possible. It would however swap the former’s steam plant for a CODOG installation, which took up a lot less space, allowing for a significantly smaller hull. Malafon was deleted from the design because there was no space for its bulky magazine (and it performed underwhelmingly to begin with), and the second 100mm turret was also skipped to avoid bow-heaviness. The electronic suite remained identical. Seven ASW hulls and four air defence hulls were approved to replace the ASW and AAW variants of the T47 and T53/56 type one by one; the T47 command version had already been replaced by the Tourvilles, and a follow-on for the radar picket version (four T53s) was not considered necessary, thus a reduction in destroyer strength by four units (three if you count the one-off Aconit, which was a dedicated ASW vessel) was accepted. At that time, the SSBN fleet ate most funds, and the surface fleet could be happy to get at least eleven new destroyers (of which two were later cancelled).
The new type was dubbed F70; after the T56, France did not designate another ship class as Torpilleur, instead calling destroyer-sized vessels up to DLG size Frigates. The first batch of four ASW ships became the Georges-Leygues subtype. The class ship was delivered in late December 1979, carrying the first operational Crotale SAM system in the fleet, but still without Satcom.
The second unit, Dupleix, had Satcom upon completion in 1981. The third vessel, Montcalm, was identical when completed in 1982.
The fourth ship, Jean de Vienne, slightly differed; she was the only one to mount an additional deckhouse immediately abaft the mast, and she had a more modern decoy launcher (Dagaie instead of Syllex).
Modernization of these ships was undertaken in a rather piecemeal fashion, IMHO not warranting a drawing for every step taken. By the turn of the century, the class ship had received Satcom and Satnav, additional jamming gear and four 12,7mm machineguns. Modernizations to the Sonar suite were not externally visible. The hull was strengthened with an external strake similar to the one installed in the Tourvilles. Georges Leygues was mostly used as a TS after 1999, but occasionally took part in antipiracy or humanitarian missions. She decommissioned in 2013 without further modernization, and without replacement.
The other three were modernized more thoroughly. Most visibly, the open upper bridge was covered in all three, apparently because the bridge complex was too low to begin with and frequently got swamped in heavy weather. Montcalm and Dupleix replaced Syllex with Dagaie and added the deckhouse abaft the mast, as per Jean de Vienne. They augmented their Satcom and Satnav antenna array and their jamming equipment, replaced their 20mm Oerlikons with turreted 30mm Breda autocannon and added two sextuple Sadral CIWS missile launchers. Their DRBV-51 target indication radars were replaced with DRBV-15s with improved performance against very small surface targets (like sea skimming missiles). Montcalm and Jean de Vienne also replaced their single MM38 missile launchers with twin MM40 launchers, effectively doubling their long-range antisurface firepower.
Dupleix apparently never received MM40. The arrangement of her satellite antennae resembled Georges Leygues, differing from the other two. She retained her 30mm turrets throughout her service life, which ended in 2014 when she was replaced by the first FREMM.
The other two served till replaced with FREMM in 2017/8. For some reason, they replaced the 30mm turrets with a new model of 20mm cannon, received a new model of commo antennae and added more ESM gear on the mast. Montcalm was the only unit of her class which upgraded the DRBV-15 to the B variant with a larger reflector and improved performance.
Jean de Vienne on the other hand was the only one which replaced the Syracuse 1 with Syracuse 3 satellite antennae, with significantly bigger radomes. She also was the only one with a small radome of (to me) unknown purpose on the funnel platform, which remained empty on Montcalm and Dupleix.
The rest of the class to follow.
Cheers
GD