Jacob van Heemskerck class frigates of the Chilean Navy

Written by D-Mitch 

CS Almirante Latorre (FFG-14). Photo: Armada de Chile

The Jacob van Heemskerck class or else L-class of Chilean Navy (Armada de Chile ) is a class of two anti-aircraft warfare (AAW) frigates. These are ex-Royal Netherlands Navy (Koninklijke Marine) frigates and they are the air-defence version of the Kortenaer (Standard or else S-class). These two AAW frigates were built as replacements after two of the Standard class frigates (frigates n.6 and n.7) that were under construction for the  Royal Netherlands Navy were sold to Greece (Hellenic Navy) in 1980-81. The two vessels were launched the period 1983-84 and they were commissioned in 1986. In 2005 the two ships were sold to Chile. In Chilean service, the F-812 Jacob van Heemskerck was renamed FFG-14 Almirante Lattore and the F-813 Witte de With was renamed FFG-11 Capitán Prat.

CS Capitan Prat (FFG-11) in formation with an M-class. Photo: Armada de Chile

The general characteristics of the class is a displacement of approximately 3,800tons at full load, length of 130.5m, beam of 14.6m, maximum speed of 30 knots and a range of 4,700n.m. with the speed of 16 knots. The crew is about 190 while the total capacity is 200 passengers. The ships are provided with command facilities for a Task Group Commander and his staff. In consistence with specialization to the AAW functionality the medium calibre gun and the hangar are sacrificed. The propulsion is Combined Gas Or Gas (COGOG). It takes less than a minute to start the gas turbines, and within two minutes the ship is at full speed.

Modified photo of L-class frigate of Chilean Navy. For a high resolution image click here.

Armed SM-1 launcher of a Chilean L-class frigate

Conceived as air defence frigates, the primary anti-aircraft equipment, except the Sea Sparrow launcher, 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. The Mk 13 missile launcher replaced the helicopter hangar and deck of the Kortenaer class frigates. 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 (outer ring: 24; inner ring: 16). 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 but Chilean Navy has not upgraded the sensors and the launcher to receive this variant. 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 important secondary capability against naval targets. It is not known yet if the Chilean Navy will proceed with the replacement of the SM-1 missiles and the required upgrades as soon this Standard variant will be put out of service.

Mk 13 launcher

Mk 13 launcher

Mk 13 launcher

CS Capitan Prat (FFG-11). Photo: Armada de Chile

The only guns that the ships have are  two Oerlikon Mk10 20mm guns at each side of the main mast. The Oerlikon Mk10 20mm gun has a maximum firing range of approximately 4,500m while the rate of fire is approximately 450rds/min. The drug magazine holds 60 rounds.

Aft section of a Jacob van Heemskerck class frigate

 

Sea Sparrow launcher of Capitan Prat; notice the hatches for
the automatic reloading. Photo: Armada de Chile

The anti-aircraft protection of the ships is supplemented by a Raytheon 8-cell Mk29 Guided Missile Vertical Launching System (GMVLS) for RIM-7M/P Sea Sparrow Surface to Air Missiles (SAMs). Originally developed as an air-to-air missile by Sperry and the U.S. Navy, the later versions were developed and produced by Raytheon and General Dynamics. Sea Sparrow is a short/medium-range, all-weather, all-aspect, semi-active guided missile designed primarily for the ship self defense role. The guidance system of the -P- variant allows mid-course upgrades and the ability to accept delayed lock-on. Sea Sparrow, is used for shipboard point defense on more than 150 ships of various classes for the U.S. and numerous other countries. The RIM-7P is the most recent model of the Sparrow family of missile systems, which began initial deployment in 1956 and has become the standard upon which many worldwide systems are based. The 7P model features performance improvements executing a variety of maneuvers in heavy clutter environments and much lower altitude air and surface target capability. Additionally, it is more time immune to the ever challenging countermeasures threat. The speed is close to Mach 4 and the range greater than 25km. The new guidance system of the -P- models give also to Sea Sparrow missile a very useful secondary anti-shipping role that allows it to attack smaller boats. The Mk29 launcher can launch a missile every 2 seconds. Each frigate carries 24 missiles; the reloading is performed automatically in contrast with the launcher of the Kortenaer/Standard class, that's the reason why L-class ships lack the OTO Melara 3in gun of their sisters.

The two Chilean frigates. Photo: Tomcat_I

The two Chilean frigates. Photo: Tomcat_I

Goalkeeper of Capitán Prat. Photo: Tomcat_I

The anti-missile protection is provided by a Close In Weapons System (CIWS), the Thales Goalkeeper. According to Thales, Goalkeeper is an autonomous and completely automatic weapon system for short-range defence of ships against highly manoeuvrable missiles, aircraft and fast manoeuvring surface vessels. The system automatically performs the entire process from surveillance and detection to destruction, including selection of the next priority target. However, manual override is possible at any stage in the sequence. Goalkeeper incorporates the 30 mm, 7-barrel GAU-8/A Gatling gun with special missile-piercing discarding-sabot (MPDS) ammunition, operating on the kinetic energy principle. The combination of MPDS ammunition and a firing rate of 4200 rds/min (!) gives the system the power necessary to destroy missile warheads. A high detection probability for small targets is ensured in all weather conditions by the use of a high-power, I-band search radar. Pin-point target tracking is achieved by the dual frequency I/K-band track radar. Continuous search with track-while-scan ensures rapid engagement of the next priority target in multi-target scenarios. Watch some nice videos of the system's performance here and here.

View of an L-class frigate. Photo: ssbn70

Three Harpoon canisters amidships. Photo: Jorge Molina Herrera

Each frigate carries eight (8) Boeing RGM-84D/G Harpoon anti-ship missiles in two Mk141 quad launchers installed amidships. These missiles have a range greater than 120km, a sub-sonic of speed of 860km/h (Mach 0.9) while they carry a warhead of 221kg. Harpoon missile has a low-level, sea-skimming cruise trajectory, active radar guidance and it is capable to perform pop-up manoeuver which it is a rapid climb of the missile to about 1,800m before diving on the locked target.

Mk 32 torpedo launcher, view from
the interior of a ship

Twin Mk32 torpedo launcher of a
Greek S-class. Photo: N.Che Ypologos

For Anti-Submarine Warfare (ASW) the L-class ships are equipped with two twin Mk32 Mod 9 324mm torpedo launchers in fixed positions (similarly to S-class) for Honeywell Mk46 Mod 5 active or passive/active acoustic homing lightweight torpedoes. These torpedoes have a range of approximately 8,500-11,000m at 45 knots (maximum speed) and they carry a very powerful warhead of 44.5kg for this category of lightweight torpedoes. They are designed to attack fast submarines and to engage them even over 400m below sea level as well as surface targets (latest variants such as Mod 5).

The two L-class air-defense frigates of Chilean Navy

SMART-S of L-class frigates.
Photo: Tomcat_l

Thales SMART-S is the E/F-band (S-band) medium-to-long range 3D multi-beam acquisition radar for targeting of the ships. This system has replaced the previous DA-05 medium-range surveillance and target indication radar system. SMART-S is capable of automatic detection of targets (multi-target tracking capacity), followed by automatic track initiation and accurate tracking of these targets. It simultaneously deals with high-priority targets such as very small and fast low-flying or high-incoming antiship missiles and all other types of air and surface targets. Smart-S makes use of modern radar and signal processing techniques, such as a multiple-stripline receiving antenna, digital FFT beam forming, and FFT doppler processing, which drastically reduces susceptibility to clutter and jamming. Smart-S' 3-D capabilities are therefore virtually invulnerable to degradation from both natural environmental effects and intentional jamming. This provides an essential contribution to the threat evaluation process, especially in multiple-attack scenarios. It results in an accurate and timely target information exchange with the weapon control systems, enabling them to perform the fastest possible lock-on. The antenna system is bi-axially stabilized, using a lightweight hydraulically controlled platform, to enable a high mast position. Finally, the entire system has extensive automatic built-in test facilities and is easy to install and maintain. The system can detect a 0.1m² target at 45km while for 2m² target the range is increased to 90km and with speeds as high as Mach 3. The tracking capacity is 40 tracks for surface targets and 160 for air targets.

Frigate Jacob van Heemskerck. Notice that the ship has not received yet the
SMART-S radar and she has the DA05. Photo: Matterson Marine Collection

LW-08 radar of Capitan Prat frigate. Photo: Tomcat_l

The Thales LW08 is a 2D radar system for long-range air surveillance in D-band (L-band), providing target indication to weapon control systems. LW08 presents a clear picture of the environment; it does so, reliably, under any circumstances. LW08 performs with great frequency agility over a wide band, due to its synthesizer-driven TWT transmitter. Excellent performance under various clutter conditions is ensured by the wide dynamic range receiver with application of digital video processing, supported by circular polarization. The LW08 antenna has a low side-lobe level, which assists the system in operating under ECM conditions. The radar can detect a small missile from 100km or a fighter aircraft from 230km flying with Mach 4 while the tracking capacity is 400 tracks. Minimum range is 2km. The LW08 radars of the modernized frigates have an increased performance.

CS Capitan Prat (FFG-11)

CS Almirante Latorre (FFG-14)

From top to bottom: SMART-S, STIR 1.8, STIR 2.4,
Scout (left), ZW06 (right). Photo: Tomcat_l

Jacob van Heemskerck class frigates are equipped with two different variants of the STIR family of multi-weapon control systems for controlling SM-2 surface-to-air missiles and the 3in naval gun. Each frigate has one Thales STIR 1.8 medium-to-long range tracking and illumination radar (1.8m antenna). The other variant of the STIR family that the ships are equipped with is the Thales STIR 2.4 long-range radar tracking and missile illumination system (2.4m antenna). Each frigate is equipped with two such systems. STIR 2.4's long range tracking and missile illumination performance support ship and area defense with Semi Active Homing missiles such as the SM-2 surface-to-air missiles. Their design is optimized for stealth target detection in demanding littoral and ECM environments. STIRs are highly capable medium-to-long range tracking and illumination dual-band (I/K) radar systems. A full set of electro-optic equipment (TV/IR/laser) complements the system for optimal performance in demanding environments, The system has been designed primarily to control point and area defence missile systems such as NATO Sea Sparrow, ESSM, Aster and Standard Missiles. A secondary application is the direct control of various caliber guns. The extreme stable front end results in excellent detection of small targets in sea and land clutter environments. The high dynamic range of the low noise receivers in combination with advanced coherent Doppler processing ensure the detection of stealth targets in heavy clutter. It might be presumed that the STIR 1.8 has been upgraded to High Power (HP) from TWT and thus its performance is increased. The instrumental range (air and surface) is 120km for the I-band and 36km for the K-band. The isntrumental range for the STIR 2.4 HP (High Power) exceeds the 500km (effective range for 1m² target is about 150km for the HP version).

CS Almirante Latorre (FFG-14)

CS Capitan Prat (FFG-11)

Atop the bridge of Capitan Prat the
Scout radar is at the left and to the
right it is the ZW06 radar

ZW06 radar of Almirante Latorre

The Thales ZW06 is a surface search and navigation radar operating in the I-band (X-band). This radar is particularly suited for surface search, low elevation gap filler, helicopter control and navigation. The transmitter is coherent for clutter and jamming rejection. The radar can detect a 10m² target at 14n.m. The Thales SCOUT Mk2 is a Low Probability of Intercept (LPI) short-to-medium range surface surveillance and tactical navigation radar. The system can be operated remotely (radio or line connection). It is an all-weather fully solid-state system of high reliability operating in X-band radar featuring Frequency Modulation Continuous Wave (FMCW) and therefore has an extremely low output power which makes the system ideal for cover operations in hostile environments where radar silence is required and thus its transmissions cannot be detected by ESM systems or radar warning receivers. SCOUT Mk2 outstandingly detects targets in adverse sea clutter conditions, thanks to its very small range cell size. The system is also very suitable for coastal surveillance. A 1m² can be detected at 5n.m., a 100m² at 15.5n.m.

Almirante Latorre (FFG-14). Photo: Damien Horvath

L-class frigate without pennant number. Photo: Jorge Molina Herrera

Each vessel is equipped with two Thales Target Designation Sights (TDS) that provide means for optical investigation, target designation and weapon firing. The TDS is equipped with binoculars and the latest version includes a Laser Range Finder. Bearing and elevation data are fed into the CMS system but the TDS can also be used for emergency control of a gun or CIWS system. The importance of the function of the TDS is re-emphasized against asymmetric tactics such as piracy and insurgency.

Almirante Latorre frigate. Photo: Armada de Chile

SRBOC launchers of Capitan Prat frigate. Photo: Tomcat_l

The decoy launchers are the BAE Systems Mk 36 Super Rapid Bloom Offboard Countermeasures (SRBOC) Chaff and Decoy Launching System. It is a shipboard, deck-mounted, 6-barreled 130mm mortar-type array that launches type-specific countermeasures against a variety of threats. Following launch and dispersion, Mk36 SRBOC chaff and infrared countermeasures are designed to lure hostile missiles away from ships under attack by creating false target sets. The Mk36 SRBOC launching system is controlled from the ship’s combat management system (see last paragraph), and it is dependent on information provided by the ship’s detection and threat analysis equipment. The Mk36 SRBOC consists of the Mk137 launcher, firing stations at the bridge and CIC, the Mk160 power supply, Mk5 Mod2 or Mod4 Ready Service Lockers (RSLs), and a selection of munitions. Each vessel of the class is equipped with four Mk137 launchers. In Chilean service, except the SRBOC launchers, different kind of decoy launchers have been added also, perhaps of Israeli origin.

CS Capitan Prat (FFG-11) in formation with an M-class. Photo: Armada de Chile

SATCOM (top) and small radomes of
RAMSES. Photo: Tomcat_l

The electronic warfare system of the class is the Signaal's I/J-band Reprogrammable Advanced Multimode Shipborne ECM System (RAMSES) or else SLQ-02. The system uses a vertical pair of egg-shaped radomes on each side of the ship under the SATCOM radomes. Each EW radome carries an identical Luneberg lens antenna; one of each pair tracks the threat the other jams. The tracking and jamming antennas are well separated so there is no need to pause for look-through while jamming. Each pair operates independently so two targets (one on each side) can be jammed simultaneously.

Frigate Capitan Prat. Photo: Vermerris

The main mast. By jacob6

SPHINX exactly above the STIR
and below SMART-S

The Signaal's System for Passive Handling of intercepted X-missions (SPHINX) is included also in the electronic equipment of the ships. Eight-port DF antennas are wrapping the base of WM25 combined surface search and fire control radar while three omnis are at the masthead. Each sector of the DF antenna has five antennas including a horizontal cone. SPHINX can track 14 signals and can lock onto three of them. SPHINX automatically warns of radars lock-ons and it can blank out selected signals. The system's digital output can be passed to an ECM system such as RAMSES. All the vessels are equipped with either a  Canadian Westinghouse SQS-509 hull-mounted; active search and attack sonar. The combat management system of the ships is the Signaal (now Thales) SEWACO VI.

Frigate Almirante Latorre FFG-14. Photo: Victorddt

Bibliography:

• http://www.damennaval.com
• http://www.armada.mil.cl
• http://www.thales7seas.com
• https://www.thalesgroup.com
• http://www.boeing.com 
• http://www.baesystems.com
• https://www.natoseasparrow.org
• http://www.gd-ots.com
• http://www.navweaps.com
• http://www.raytheon.com
• The Naval Institute Guide to World Naval Weapon Systems