The French knew that minelayers would be needed in any new European conflict. Mining the English Channel to deny it to enemy shipping and submarines was an important part of the combined Royal Navy, French Navy strategy. The Royal Navy laid down their Adventure class minelayers and the French followed suit with the first pair of Pluton Class ships. While classed as minelaying cruisers (CLM) they were also able to be used as training ships and as troop transports, or bits of all three, the huge mine deck could be split with plywood to make up any design required. Armed with the same twin 6.4" as the Leon Gambetta class, these were recycled turrets removed from earlier armoured cruiser and pre-dreadnought battleship classes. These guns gave the two ships decent weapons to fight off the most common ships that would be sent after them - enemy destroyers. AA weaponry was not stinted either, 37mm, 20mm, and single 3.9" sprouted like a porcupine from the ships. But the ships most natural defense was speed. The ships were powered to achieve 33 knots, the same as the Duguay Trouin and Duquesne class cruisers which would be their cover force for offensive missions.
The first two ships were completed in 1932 and proved to be good investments. A further pair of the same class were laid down in 1933 for completion in 1936. The main difference between the pairs was the main armament. The later pair were to be fitted with twin 5.1" dual purpose turrets in place of the 6.4". This also meant that the single 3.9" were no longer required and were replaced between the funnels with a catapult and aircraft that was useful for their 'other than minelaying' duties. Extra 37mm were added over the earlier ships. Recognition of aircraft being a countermeasure to fast minelayers added extra AA weapons and the upgrade in the main armament.
All four ships went into World War Two, but the Pluton was an early loss. September 1939 the ship was lost to an internal explosion while being loaded for minelaying operations in the Channel. Two more were lost on mining operations, with only Auguste making it to the end of the war.
