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Friday 21 November 2014

Comandanti class and Sirio class offshore patrol vessels of the Italian Navy

Written by D-Mitch

Comandanti class patrol vessel.
Photo: Marina Militare Italiana
Sirio class patrol vessel.
Photo: Marina Militare Italiana
The most modern offshore patrol vessels in service with Italian Navy (Marina Militare) are the ships of the Comandanti and Sirio classes, two classes of the same design that share some common equipment.  The four patrol vessels of the Comandanti class were built by Fincantieri and they were delivered to the Italian Navy the period 2002-2004. The program is also known as Nuove Unità Minori Combattenti (NUMC). The last vessel, the Foscari, was built with composite superstructure made off glass reinforced plastic instead of steel having in that way less mass and therefore resulting in reduced fuel consumption and improved life cycle of the ship. The two vessels of the Sirio class, also known as Nuove Unità di Pattugliamento d'Altura (NUPA), were commissioned in 2005. The NUPA program gives less emphasis on stealth characteristics, performance and equipment for operations in low intensity conflict environment such as NUMC program as the main mission of the Sirio class patrol vessels is to safeguard national interests in the fields of anti-pollution and rescue services. Therefore, among others, Sirio boats lack the main naval gun and the fire control system, they have less powerful engines and they have no hangar but only a flight deck. However the ships have all the provisions to be equipped as their older sisters. Both classes can various missions such as patrolling and surveillance at sea, control of maritime traffic and inspections, humanitarian relief operations, search and rescue operations, control of the maritime borders, protection of merchant shipping and fisheries, support operations and many more. 

Modified photo of Comandanti class offshore patrol vessel. In high resolution click here.
Modified photo of Comandanti class offshore patrol vessel. In high resolution click here.
The general characteristics of the class is a displacement of 1,520tons, length of 88.6m, beam of about 10m, maximum speed of 25knots and range of 3,500n.m. with the speed of 14knots.  The ship has a crew of 60 persons while there is space for more. Each vessel has a flight deck and a retractable hangar that can accommodate an AB212 or a NH90 ASW helicopter. The vessels carry two large Rigid Hull Inflatable Boats (RHIB).

Modified photo of Sirio class offshore patrol vessel. In high resolution click here

Super Rapido/Strales. Photo: Marina Mlitare Italiana
The ships of the Comandanti class have one main gun on the bow deck which is the  OTO Melara Super Rapido 76mm/62cal gun. There is provision for future installation on the Sirio class ships. Initially the 76mm guns were housed in non-stealth cupolas but later they were integrated in the STRALES system which consists of the naval gun, a Radio Frequency Guidance System with the electronic control unit and the DART ammunition. STRALES is an all-weather system that was designed to engage and to destroy multiple manoeuvring targets with the use of guidance ammunition for increased accuracy and therefore lethality. STRALES includes a Radio Frequency Guidance System provided with a mechanical frame to be connected to the gun-mount structure. A gun shield is provided with a watertight cover which can be automatically removed to deploy the guidance antenna; once actual target position and stabilisation data are available, STRALES operates as a stand alone system. The DART projectile is equipped with the new DART microwave  programmable  multifunction  fuse. The effective operating range is greater than 8km while the maneuverability is higher than.. 40g! A new Multiple-Feeding (MF) ammunition loading system for the 76/62 mm is also available as a separate kit which is able to select any ammunition contained in the branches regardless of its position (typically, DART and standard ammo). The gun can intercept air and surface targets at a distance of 4 km (at 85 degrees) and 16 km (effective range 8 km, 6km the effective range against anti-ship missiles) unleashing 120 rounds per minute weighting greater than 6kg each. The gun has excellent performance in any kind of role, such as air defence, anti surface, anti-missile and shore bombardment role. It is claimed by OTO Melara that these guns can engage 4 missiles before they reach the ship.

The retractable hangar of Cigala Fulgosi
Italian SH90 (NH90)

Borsini of Comandanti class
with the old gun cupola

Bettica of Comandanti class

Foscari with new turret


OTO Melara 25mm gun system
The ships of both classes have also two OTO Melara Oerlikon KBA 25mm/80cal  guns which are installed one to port and one to starboard. The guns are stabilized, electric servo-drive assisted, while a weapon control is featured in order to allow the gunner to remain steady at any barrel elevation, laying the gun with the maximum accuracy even against targets at maximum elevation. A conventional aiming system is fitted to the mount, but also an IR sight with integrated ballistic reticule is available. The rate of fire is about 650 rounds per minute and the effective range for aerial targets is about 2,000m. The gun has two 126-round boxes on each side of it. Perhaps the ships of the Comandanti class could also be equipped with SSM launchers as there is a good space amidships for such installation.

76mm naval gun on the bow deck of a Comandanti class patrol vessel. Photo: Marina Mlitare
Selex RAN30 surveillance radar.
Photo: Selex
The ships are equipped with an X-band multi-mode surveillance radar Selex RAN-30X (SPS-791). RAN-30 X/I features up to four operational roles: Surface and Air Surveillance mode (detection and tracking of small air/surface targets; max. range 102km); Navigation and Helicopter control (high antenna rotation speed for navigation close to the coastline; max. range 41km); Over-the-Horizon (OTH) detection (low antenna rotation speed and long range detection capability; max. range 200km); Anti-seaskimmer missile detection (max. rage 25km). This mode has an high antenna rotation rate to ensure the detection and tracking of very small targets manoeuvring in clutter environment and featuring very low Radar Cross Section (R.C.S.). It is an automatic detection/tracker radar that can carry up to 255 system tracks (air and surface targets).

Hatch has opened to retrieve/release an RHIB

Selex RTN25X FCS. Photo: Selex
Part of the electronic equipment of the Comandanti class (there is provision for future installation on the Sirio class vessels) is a Selex NA-25X Radar and Optronic Fire Control Systems (FCS). NA-25X which is a modern fire control system based on the ORION RTN-25X tracking naval radar, a J-band fully coherent equipment which is characterised by anti-nodding, extensive ECCM and anti-clutter features together with high tracking accuracy. A set of two EO sensors (TV camera, IR camera) can be mounted on the radar director, to enable firing assessment and to provide an alternative line-of-sight on the same target. A third sensor (Laser Range Finder) can be mounted to provide a complete EO tracker facility. NA-25X can be provided with a dedicated multifunctional console or controlled by any console of the Combat Management System (CMS). The FCS can be easily integrated in every CMS and completely remote accessible. A couple of Targets Designation Sight (TDS) enhance the FCS configuration. Through an internal additional function, NA-25X system can be integrated inside an Artillery System (including at least two FCSs), to optimize the use of all onboard guns against multiple concurrent targets (missiles, air and surface targets). The system perfomrs the following tasks: radar and optronic autonomous search with automatic/manual self-designation, surveillance and self designation on ship's search radar video, automatic engagement of evaluated priority target up to firing action, automatic air/missile/shore and surface targets tracking, automatic detection of launched missile, control of up to three guns with different calibres in the anti-air/anti-surface warfare and CIWS roles, line-of-sight/line-of-fire stabilization and Track While Scan (TWS) on external naval data.



Sirio during tests

Janus EO sensor. Photo: Selex
Each vessel of both classes has been equipped recently with a Selex Janus-N a stabilised high performance multi sensor that delivers medium to long range panoramic sight under any kind of environmental conditions (weather, day/night, rough sea etc.). The sensor is capable of tracking any kind of targets. he electronic equipment completes a GEM SPN-753G (V) 10 ARPA navigation radars that performs auto-tracking of up to 50 targets, a SATCOM UHF system and other communication antennas (satellite communications, INMARSAT).

Comandante Foscari (P-493) in 2010, notice the absence of the EO sensor. Photo: Jimmy C. Pan, US Navy
Until today the ships of the two classes have not been equipped with an ESM/EW system or chaff launchers. Elmer provides the communications system.

Sirio, lead ship of the Sirio class
Foscari, last ship of the Comandanti class

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