In the last months of 1940 the Supermarina (headquarters of the Italian Regia Marina) understood that the escort of the traffic heading overseas was starting to present difficulties which had not been foreseen and which seemed hard to overcome. Besides, the scarcity of available naphtha advised against an excessively prolonged utilization of units, above a certain tonnage, for convoy escort missions. However, the threat from the Royal Navy, which could interrupt the flow of supplies, forced to use large units as well, which was a high risk, if considering that the strong fuel consumption would have led, sooner or later, to the immobilization of the fleet. It was then decided to build units of the same type than the British corvettes, adapted to escort, particularly to the anti-submarine one, in such a way that they were quickly built, with a reduced initial cost and good qualities, nautical and structural ones. The research began in the first months of 1941, and the 3rd October 1942 the first corvette, the "Gabbiano", entered service. Out of the other 59, all of them already started, only 29 could be delivered to the Regia Marina due to the arrival of the armistice. The units in question, which had been designed to operate as "guard dogs" by quickly moving within a "herd" of merchant ships which advanced at a maximum speed of 11-12 knots, had an interesting propulsion system, constituted by two Diesel engines actuating in two axes, with a total power of 3500 horsepower, which during anti-submarine hunt operations gave way to two silent electric motors, of 75 horsepower each, fed by accumulators and capable of moving the ship at a speed of 7 knots without betraying her presence to the hydrophones of the attacked submarine. The units had echo-goniometric systems as well. The installation of a demagnetization system allowed to face with enough safety the danger posed by magnetic mines. They showed themselves as good units in overall and many of them had a very long operative life after the war. Among these was the "Baionetta", which was decommissioned by the Marina Militare the 1st January 1971 after long years of training service. In 1977 the corvette "Ape", modified as a raiding support ship, was still operational in the role of pilot ship.