Naval Analyses: Durand de la Penne class destroyers of the Italian Navy

Written by D-Mitch

D560 Luigi Durand de la Penne, lead ship of the class.
Photo: Marina Militare Italiana

Elegant lines and powerful armament. These are the characteristics of the Durand de la Penne class destroyers of Italian Navy (Marina Militare), the last class of non-stealth major surface combatants in service with Italian Navy and some of the most beautiful and well-armed warships ever built. Two ships belong in this class of anti-aircraft warfare (AAW) destroyers, the Luigi Durand de la Penne and the Francesco Mimbelli. The ships were built by Fincantieri and they were commissioned in 1993. Initially there was a plan to built four ships of the class but the second pair was cancelled as Italy joined France in the Horizon project for AAW destroyers. The ships of the class are advanced and quite capable to perform any kind of mission given due to their extensive armament and electronic equipment.

D561 Francesco Mimbelli, the second destroyer in the class. Photo: Marina Militare Italiana

The aft 76mm gun atop of the hangar
and the SSM/ASW launchers amidships

OTO Melara 127mm, Albatros launcher
and 76mm guns of Francesco Mimbelli

The general characteristics of the class is displacement of 5,400tons at full load, length of about 148m, beam of 16m, maximum speed of 32knots (!) and a range of 7,000n.m. with a cruising speed of 18knots. The ship has a crew of 350 persons, a typical characteristic of the warships of that era. Each destroyer can accommodate two AB212 ASW helicopters in its double hangar while heavier helicopter types such as the EH101 or NH90 can land on the large flight deck but cannot fit into the hangar (perhaps the hangar has been modified to fit also NH90). As an evolution of the Audace destroyers, the ships of the class have a heavy gun armament; each destroyer has one main gun on the bow deck, the dual-purpose OTO Melara Compatto 127mm/54cal dated from the late '60s. The mounting has 66-ready-to-fire rounds in three drums located below the gun house. Each drum can hold a different ammunition type and each can be independently selected; the drums are automatically reloaded even while the gun is firing. The gun is capable to intercept air and surface targets at a distance of 7km and 15km respectively (24km maximum range) unleashing 45 rounds per minute weighting greater than 32kg each. Watch a video of the gun in action here. The previous month it was reported that the gun of destroyer Francesco Mimbellli has been upgraded with the VULCANO module (source). VULCANO system consists of four key sub-systems: the medium caliber 127/64 LW Gun assembly, the Automated Ammunition Handling System, the Naval Fire Control Support and the VULCANO family of ammunition. The system is intended for surface fire and naval gunfire support as main role and anti-aircraft fire as secondary role. The 127/64 LW - VULCANO is equipped with a modular feeding magazine, composed by 4 drums with 14 ready to fire ammunition each (56 in total), reloadable during firing, and highly flexible in terms of selection of ammunition, independently from their position in the drums. Ammunition flow is reversible as rounds can be downloaded automatically. The 127mm VULCANO ammunition family, is composed by Ballistic Extended Range (BER) and Guided Long Range (GLR) ammunition with different multifunctional fuses, sensor and final guidance that extend the range of the gun up to 100km. The rate of fire is 32rds per minute. General Purpose FREMMs are getting the highly Automated Ammunition Handling System for the 127/64 mm gun, which holds 350 127mm shells in addition to the 56 in the four reload drums of the gun turret.

Francesco Mimbelli's 127/54C gun under upgrade
with Vulcano module. Via Larry, difesa.forumfree.it.

In addition to the 5in gun, each destroyer is equipped with three fully automatic OTO Melara Super Rapido 76mm/62cal guns; the two of them are located at each side of the Albatros missile launcher which is located behind the 5in gun. Each 3in gun is capable to intercept air and surface targets at a distance of 4 km (at 85 degrees) and 16 km (effective 8 km) respectively unleashing 120 rounds per minute weighting greater than 6kg each. The effective range is between 5-8km. The revolver magazine in the mount holds 85 ready rounds. With the use of sophisticated fuses the guns can engage at 6 km even anti-ship missiles. The guns are remotely controlled but there is provision for an emergency local control.

Modified photo of Durand de la Penne class destroyer of the Italian Navy. In high resolution here.

Launch of an Aspide 2000 from Albatros Mk2 launcher

Immediately behind the 5in gun, it is installed an MBDA Albatros Mk 2 8-cell launcher for Aspide surface-to-air missiles. The system launches two types of semi-active missiles, the standard Aspide Mk2 with 15km range for point defense and the new Aspide 2000 with 25km range for limited area defense. Both versions have a speed of Mach 2 and they carry a 35kg warhead. Aspide is a well proven, all weather and highly ECM (electronic countermeasure) resistant naval system designed to counter aircraft, UAVs, helicopters at sea, as well as sea skimming and diving anti-ship missiles and PGMs. The system is integrated completely with the fire control systems of the ship which are also guide the guns. Aspide missile uses the same airframe of Sea Sparrow (RIM-7) SAM. One or two missiles can be simultaneously guided against the same target. The system provides for a Single Shot Kill Probability greater than 0.8 with a single missile and 0.96 with two missiles. Each destroyer carries 16 Aspide missiles ammunition (which is mounted below the launcher deck) in addition to the 8 ready-to-fire loaded in the launcher. A Riva-Calzoni system can quickly load 4 at once in the 8-cell launcher. The maximum firing rate is one missile every 2.5 seconds.

Riva-Calzoni's automatic reloading system for the Albatros launcher.
Photo: Military Technology Magazine 1982

Aft 3in gun and Mk13 launcher armed. Photo: Samuele Risolo

Another view of the aft 3in gun and Mk13 launcher

Conceived as air defence destroyers, the primary anti-aircraft equipment, except the Albatros launcher and the guns, it is a single-arm Raytheon Tartar guided missile launching system (GMLS) Mk13 Mod 4 launcher for Standard SM-1MR (RIM-66E) surface-to-air missiles. Italian Navy has not replaced the SM-1MR (Medium Range) missiles with the newer and more advanced SM-2MR missiles despite some reports the last decade about a possible purchase by Italian Navy of this variant of Standard missiles after the New Threat Upgrade programme (NTU). NTU was a United States Navy program to improve the capability of ships equipped with Terrier and Tartar anti-aircraft systems. According to the U.S. Department of Defense, in July 2000, Italy requested a first batch of 50 SM-2MR (Block IIIA) missiles with weapon system components, four MK 74 Mod 15 (X-band) missile fire control systems, containers, test sets, systems, transmitters, modification kits, spare and repair parts, support and test equipment, publications and technical documentation, training, U.S. government and contractor technical assistance and other related elements of logistics support. The estimated cost was $135 million (U.S. Department of Defense, Release No: 440-00, July 24, 2000). The source reported that "Italy will use these missiles as replacements for older missiles currently in the Italian fleet. Italy, which already has Standard missiles in its inventory, will have no difficulty absorbing these additional missiles". However this purchase never took place. It can be confirmed on the Raytheon's website where the eight counties-users of the SM-2 are reported and Italy is not among them. the The launcher is capable of firing the Standard missile at a rate of one per eight seconds; the Mk 13 Mod 4 GMLS can stow up to 40 missiles. The SM-1MR has a speed of Mach 2.5 and a range of approximately 45km (the range is almost double for the SM-2MR, about 70-80km). In addition to the greater range, the SM-2MR has improved performance over low attitude targets and a greater resistance to ECM. The RIM-66E variant has the monopulse seeker that developed for the SM-2MR, the Mk115 warhead that is being used by the SM-2MR, proximity fuze and a high grain explosive warhead (125kg?). The missiles are guided by inertial navigation (the SM-2MR only) and there is a communication link for mid-course commands and monopulse semi-active radar homing for the terminal guidance phase of the interception. The Standard missiles have also significant secondary capability against naval targets.

Mk13 launcher

Mk 13 launcher of USS Byrd (DDG-63) destroyer

Mk13 launcher

Twin Otomat launchers and single MILAS launchers on
a Durand de la Penne class destroyer

The destroyers carry the MBDA Otomat/Teseo Mk2A block IV guided anti-ship missile in four twin launchers amidships. The missile has a range of up to 180km, a high subsonic speed Mach 0.9 and carries a warhead of 210kg capable piercing up to 80mm of steel. The warhead is designed to explode inside the ship with the force of the explosion directed to the bottom of the target ship. Capable of ranges from 6-180km in all directions, the system relies on powerful mission planning (3D way-points, terminal sea skimming profile, simultaneous attack from different directions). Target data is derived from the ship's Command System or taken directly from the ship's surface search radar. Mission Planning allows the selection of different firing modes (such as Fire and Forget or midcourse guided) and of specific trajectories and evasive manoeuvres. Cruise and approach phases may be either fully inertial or partially guided from the launch ship through a radio-link. Mid course re-vectoring from a co-operating ship or helicopter is also possible. The excellent capabilities of the missile (short reaction time, Fire and Forget, INS/GPS navigation, high target selection, ECCM and anti-CIWS manoeuvres, warhead lethality with no collateral damage) allow the system to operate effectively in littoral warfare environments, as well as in blue waters. The terminal attack phase is based upon an autonomous terminal guidance using an active homing head with improved target selection capabilities in complex scenarios. It should be mentioned that Otomat is one of the most powerful western anti-ship missiles having a mid course data-link and land attack capability.

HMAS Toowoomba launches MU90
torpedo. Photo: Royal Australian Navy

Eurotorp B515 324mm torpedo launcher

For anti-submarine warfare (ASW) operations the vessels have two triple Eurotorp B515 324mm (similar to Mk32) torpedo launchers for MU90/Impact torpedoes. MU90 is a lightweight torpedo with a warhead of 32.7kg, a speed from 29 to a maximum of 50 knots (!), about 10km with maximum speed and 23km with minimum speed. The maximum depth is 1,000m. The torpedo, is of fire-and-forget type and it has been designed to counter any type of nuclear or conventional submarine, acoustically coated, deep and fast-evasive, deploying active or passive anti-torpedo effectors while it has an extreme agility and maneuverability. In the main counter-counter measures are included stationary target detection capability, decoy classification and anti-jammer tactics.

Modified photo of Durand de la Penne class destroyer. For a higher resolution image click here.

MILAS ASW missile. Photo: MBDA

Instead of a full load of anti-ship missiles, the destroyers can replace some of their Otomat with MILAS anti-submarine missile system. MILAS is the European counterpart to the ASROC. Derived from the Otomat MK2 missile system, MILAS is an all weather, anti-submarine warfare weapon system designed to operate in conjunction with modern detection systems such as very low frequency active and passive sonar which provide long range detection combined with very high precision. MILAS is designed to carry and release an MU-90, or similar lightweight torpedo, close to the designated submarine position, as indicated by the ship sonar or by a co-operating ASW helicopter or MPA. MILAS is capable of ranges from 5 to in excess of 35 km in all directions. The firing system is highly automated and requires only a single operator. Once the ship’s sonar has detected an enemy submarine, the sonar contact is analysed and classified before a target designation is sent to a dedicated MILAS console. The system effectiveness relies on the capability to update the trajectory and the torpedo release point continuously during the missile flight, with the added advantage of modifying the torpedo settings in respect of target manoeuvres. The MILAS missile, featuring 360° gyro-deviation and in-flight re-vectoring to counter any avoidance measures carried out by the target, then delivers the torpedo in the immediate vicinity of the enemy submarine. On entering the water, the torpedo activates its own sonar detection and propulsion systems. Then, after a rapid searching phase, it proceeds to attack and destroy the target. With its fast reaction time, operational range and availability, the system provides the launching ship and the escorted naval formation permanent and effective defence against the submarine, be it conventional or nuclear. MILAS missiles can also be used together with OTOMAT MK 2 missiles in a common system/ launcher for combined ASW and ASuW. It is bigger than Otomat, 6m long and 800 kg. Developed in co-operation by France and Italy, MILAS is in operational service only with the Italian Navy till today.

SCLAR-H decoy launcher on a Horizon class destroyer. Photo: Enrico Veneruso

It is clear that the ships of the class are equipped with two OTO Melara/Selex SCLAR-H decoy launchers for 105mm or 118mm multipurpose rockets and not with the Matra CSEE Sagaie launchers which have been replaced.

Luigi Durand de la Penne prior the modernization with its SPS-768 and SPS-52C radars and Sagaie decoy launchers

The destroyers were initially built with the US origin Hughes SPS-52C 3D air search long range radar and the SPS-768 (RAN-3L) air search radar which both have been replaced during the last decade by the modern Selex SPS-798(V) (RAN-40L) 3D air search long range radar. This is an L-Band search radar designed to operate within complex naval combat defence systems. It ensures an instrumental detection of aircraft at a range of up to 400 km while it can track more than 500 targets simultaneously. The radar is placed at the foot of the main mast.

At the foot of the main mast the new RAN-40 while on top the RAN-21 radar.
Photo: Stefano Coglia Cagliari

As all ships that are equipped with Albatros launcher, the destroyers of the class have a Selex SPS-794 (V) (RAN 21S) 3D medium range air and surface search E/F-band radar on their main mast. The stabilized solid (vice mesh) antenna has a range of about 150km while a sea-skimming missile of a 0.1m² dimension can be detected at 10km. An Identification Friendly or Foe (IFF) is integrated into the antenna; it is placed on the top of the reflector.

D560 Luigi Durand de la Penne prior the modernization.
Photo: Luis Díaz-Bedia Astor

D561 Fracesco Mimbelli after the modernization with one AB212 on the flightdeck.
Photo: Stefano Coglia Cagliari

The pair of SPG-51D radars and one
of the three NA-30E FCS on Francesco
Mimbelli. Photo: Stefano Coglia Cagliari

Luigi Durand de la Penne.
Photo by @YorukIsik

Behind the main mast there are two Raytheon AN/SPG-51D (G/I-band) fire control missile systems that guide the Standard Missile-1 (SM-1) surface-to-air missiles to their maximum range. AN/SPG-51D radars, part of the Mk74 Missile Fire Control System, are located directly aft of the aft funnel. The systems have not been upgraded to Mk74 Mod14/15 configuration in order to guide the SM-2MR missiles as it was already mentioned Italy never proceeded in the purchase of the upgraded variant. Aircraft tracking is based on monopulse radar utilizing Pulse-Doppler radar signal processing in Mk74 Mod 11 and not the Mod 14/15 that the New Threat Upgrade (NTU) would have included. The Mk74 Mod 15 configuration includes X-band continuous-wave radar tracking in addition to pulse-Doppler tracking with the use of a secondary antenna and it supports terminal illumination, rear reference, and uplink requirements of SM-2. It provides illumination for bistatic radar operation associated with missile guidance in all configurations. The Naval Institute Guide to the World Naval Weapon Systems, 2006 reports "NTU is usually characterized as a poor man's Aegis, in that it exploits the commandable autopilot of the SM-2 missile to increase firepower without requiring a precision radar. NTU was originally associated with weapons direction system Mk 14. Like Aegis, NTU entails target illumination only near the target; up to that point, the missile is intermittently command-guided on the basis of search radar (track-while-scan) data. The lack of precision in the ships' main radars (compared with SPY-1) reduces firepower in two ways. First, command guidance is less precise, so the missile is not brought as close to the target before switching to semi-active guidance. Second, NTU ships cannot use the slaved illuminators of that system. Instead, illuminating radars have to search for and lock onto targets for terminal illumination. That increases the time per target and reduces overall firepower compared with Aegis. Even so, NTU drastically increases the efficacy of non-Aegis missile ships".

The two destroyers sailing alongside sail training ship Palinuro

It's clear that Durand de la Penne class destroyers would have been really powerful armed ships if the NTU upgrade and the purchase of the SM-2 missiles would have been proceeded but unfortunately this upgrade never went through and it was cancelled. SM-1 missiles are about to be retired from the Italian inventory (if this hasn't happened yet) so the ships maybe reclassified to frigates.

Luigi Durand de la Penne firing its main gun. Photo: Marina Militare Italiana

Halfway up the forward mast it is installed the SMA MM/SPS-702 (RAN 11L/X) air and surface search radar. This radar alternates long and short pulses for both medium range air and surface search and precise short range navigational coverage. It can be used also for target designation. The roll-stabilized mounting is sharing (together with the reflector) the associated IFF interrogator. On the foward mast there is also a GEM Elletronica MM/SPN-735 navigation X-band radar.

D560 prior the modernization.
Photo: Marina Militare Italiana

Luigi Durand de la Penne prior the modernization.
Photo: Marina Militare Italiana

Each destroyer is equipped with three (originally four) Selex NA-30E (Dardo E) radar and optronic fire control systems a system which comprised of the I-band fully coherent Orion RTN-30X automatic target acquisition and monopulse tracking radar with the addition of TV/IL/laser and IR electro-optical sensors. This system is particularly optimized to counter the low and very low altitude threat in an environment characterized by rain, sea, and land clutter, and dense ECM (electronic countermeasures) .Two of the systems are installed atop of the bridge while the third one is located at the port side, next to the aft AN/SPG-51D fire control system. Each FCS can control two weapon systems (Aspide, 5in gun or 3in gun). The system has a range of approximately 15km.

Luigi Durand de la Penne after the modernization.
Photo: Marina Militare Italiana

As it was mentioned earlier, each destroyer carries two Agusta Bell 212 ASW helicopters that can be accommodated in the double hangar. The helicopters of this type, provide an Over-The-Horizon targeting capability for the long range anti-ship missiles of the ship. Their main duty though is the ASW operations by using their dipping sonars and their A-244/S or Mk-46 torpedoes (each helicopter carries two). Other duties include long-range patrols or to carry specialist boarding teams.

NH90 on the flight deck of Luigi Durand de la Penne. Perhaps the destroyers can
accommodate into their hangars this type of helicopters. Photo: Giorgio Parodi

AB212 aboard Luigi Durand de la Penne. The ships of the class can accommodate
two such helicopters into their hangars. Photo: Marina Militare Italiana

SLC-705 jammer close to the mast

AN/SLQ-25 Nixie on USS Iowa

In the introduction it was mentioned that this type of destroyers can perform any kind of role given. And this is more than true. Except the anti-ship missiles, the guns, the two types of ASW weapons and anti-aircraft missiles, the ships are equipped with a comprehensive electronic equipment. The destroyers are equipped with an AESN-Raytheon DE 1164LF hull-mounted sonar, and an AESN-Raytheon DE 1167LF integrated towed sonar array (VDS - variable depth sonar). An additional interface unit is provided to process the signals from the VDS array. This hull-mounted and VDS configuration provides the best ASW coverage in all water conditions. As a typical equipment the ships carry the AN/SLQ-25 Nixie towed torpedo decoys. The system consists of a towed decoy device (TB-14A) and a shipboard signal generator. The decoy emits signals to draw a torpedo away from its intended target. In addition to the complete ASW electronic equipment, the ships of the class are equipped with the Elettronica SLQ-732 Nettuno integrated ECM/ESM which employs four stabilized radome-mounted antennas, SLC-705 jammers and COMINT intercept

The bridge of Fracesco Mimbelli with two NA-30 FCS atop and the forward mast; lower to the superstructure there is a 12.7mm mounting. Notice the variety of EW jammers: the DF collar around the masthead below the Tacan antenna, the omnis (passive DF jammers) on the small yardarms below it, and the high and low-band stabilized jammers on the atop and atop the bridge. Photo: Stefano Coglia Cagliari

The Comand and Control System is the Selex IPN 20 (or else SADOC-2 for Marina Militare Italiana). There is also an integrated ELMER TCL System with Link 11 and Link 14 communications.