In 1971 the Alinavi company began construction of small fast attack patrol boat named P-420 Swordfish, which was later renamed P-420 Sparviero (on the image). This company was actually a consortium formed by the Italian Government, the Italian commercial hydrofoil manufacturer Carlo Rodriquez and the American firm Boeing. The Sparviero was the first of a series of 7 boats, which were basically a smaller-scale copy of the US Navy’s Pegasus class. The concept was the same, installing powerful anti-ship missiles on a light, very maneuverable and very fast ship that would allow specific attacks against larger surface ships on coastal waters. It can be said that they are the Italian vision of the PHM (Patrol Hydrofoil Missile) concept proposed by the US Navy for some NATO countries in the early 70s.(P-422 Falcone image). The hull of these ships was built with welded aluminum plates and the superstructure was composed of welded and riveted light alloy plates. The interior of the hull was divided into 6 watertight compartments. The internal layout, from bow to stern, was as follows: crew quarters, service room, gun magazine, officers’ cabin, control room for electronic equipment and power plant, and the two engine rooms. These ships were characterized by being exceptionally stable during high-speed navigation, being able to navigate at 40 knots (74 km/h) in force 4 seas.(P-422 Falcone image). The Sparviero class was equipped with the Boeing Jetfoil system, which consisted of one forward hydrofoil, which supported around 30% of the ship’s weight, and two aft completely submerged in canard configuration. They were made of anti-corrosion stainless steel and could be retracted, the front one fitted into a structure in the bow while the two rear ones were placed vertically on the sides of the missile launchers. The automatic control of the ship’s position during navigation on the hydrofoils was carried out by a SEPA AN-700 system, made up of two aeronautical-type gyroscopes, three accelerometers and two ultrasonic sensors. The data from these devices was sent to a computer, which after analyzing it, sent the orders to the controls of the moving surfaces of the hydrofoils.(P-422 Falcone & P-421 Nibbio image). Like the Pegasus class patrol vessels, these ships had two different power plants. For navigation on the hydrofoils (lift) they had a hydrojet formed by a 4,500 hp Rolls-Royce Proteus 15M/560 gas turbine coupled to a double-suction centrifugal pump. For slow navigation they had a 160 hp Isotta Fraschini ID-38 N6V diesel engine that drove a 360º adjustable retractable propeller. Later the diesel engine was modernized, increasing its power to 290 hp. The maximum speed of the Sparviero class was 50 knots (93 km/h) and they had a range of 450 miles (832 km) at 45 knots or a maximum of 1,200 miles (2,220 km) at 8 knots.The armament consisted of a Teseo system formed by two single-cell container-launchers of Otomat Mk.2 anti-ship missiles with active radar guidance with a range of 150 km, although to reach this distance the help of a helicopter was necessary to correct the trajectory. The P-420 Sparviero (on the image) carried a single-cell launcher during trials, but later, she carried two launchers like the rest of the class. In addition to the missiles, these ships carried a 76mm OTO-Melara rapid-fire dual-purpose gun. The missiles were controlled by an AESN SPG-70 fire control radar and the gun was connected to an Orion-10X radar and a low light intensity TV system. These vessels carried an SMA SPQ 701 aerial/naval navigation radar and a MM/SSN-715 surface targeting radar along with an IFF.The Marina Militare had 7 Sparviero patrol boats that were commissioned between 1974 and 1984. The vessels were: P-420 Sparviero, P-421 Nibbio, P-422 Falcone, P-423 Astore, P-424 Grifone, P-425 Gheppio (on the image) and P-426 Condor. After an average of 15 years of service, all ships were retired between 1991 and 1999 and did not receive major modernizations. Although the possibility of installing new 6,395 hp Alison gas turbines was studied, this modernization was too expensive and was not carried out.The Japanese Navy used the Sparviero-class patrol boats as a base for its PHM Ichi-go class fast attack patrol boats (on the image), although they only used the architecture of the ship, so the weapons, power plant and electronics were totally different. The PG Ichi-go class were slightly smaller and had a 5,200 hp General Electric LM500 gas turbine with which they reached 46 knots (85 km/h). In addition, its armament was composed of two twin Mitsubishi SSM-1B Type 90 anti-ship missile launchers with a range of 150 km and a 20mm three-barreled Sea Vulcan rotary gun. Although the plans were to acquire 12 PHM Ichi-go boats, only 3 ships were built between 1991 and 1993 in the Sumitomo shipyards with Fincantieri assistance. The 3 ships were decommissioned between 2008 and 2010.
