Johann A. Revil-class destroyer
DDG-786 Johann A. Revil
|Name:||Johann A. Revil-class destroyer|
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Dar-es-Salaam Navy Yard
Kure Naval Arsenal
Mehmud-Tabnit Lagos Shipyards
Philosir Industries Dakar Yards
United Nigerian Lagos Steelworks
Utsuho Marine Technologies
Yokosuka Naval Arsenal
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|Preceded by:||Elementario-class destroyer|
|Cost:||NSD$2.90 billion (FY2014)|
|In commission:||1 March 2009|
|Length:||187 m (614 ft)|
|Beam:||22.5 m (74 ft)|
|Draft:||9.1 m (30 ft)|
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1 × IDOS Power Systems NCV4-D1 PWR (480 MWt, 200 MWe)
1 × United Nigerian PR-1100EX gas turbine/generator set (29 MW)
2 × electric motors powering D6SN integrated motor-propulsors (140,000 shp, 104 MW)
|Speed:||34 knots max, 22 knots cruise|
|Range:||50 year projected service life|
|Boats & landing |
|2 × RHIB|
|Complement:||27 officers, 340 enlisted|
|Sensors and |
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SW/ETS-971 X/S-band multifunction radar
SW/ETN-975 X-band navigation radar
SW/ETI-848 multi-spectal IRST
SW/ESH-820 sonar array
SW/EST-822S towed array sonar
|Electronic warfare |
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2 × SR/EWS-654(AM1) electronic warfare suite
2 × Mark 40 Integrated Countermeasure Dispenser
Mark 111 missile decoy
SDC-729 torpedo countermeasure system
SR/ENS-670 torpedo decoy
SSI-725 torpedo interceptor
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30 mm spaced steel box around magazines and engines
50 mm kevlar over magazines, engines, and bunkers
|Aircraft carried:||2 × QMS-50 Gannet medium ASW helicopters|
|Aviation facilities:||Aft flight deck with enclosed hangars, forward VERTREP station|
The Johann A. Revil-class destroyers are a class of nuclear-powered guided missile destroyers in service with the Punic Navy. The first surface combatant of the NP21 program to enter service, the class is derived in large part from the previous Elementario-class destroyer. It is equipped with the Stele combat management system and a large array of weaponry, including vertical launch systems, torpedo tubes, and aviation facilities for helicopters and drones.
The class began development in the early 2000s as the projected replacement for the existing Elementario and Sabah Khayyam-classes, with greater capability and nuclear propulsion to support expeditionary missions in conjunction with carrier groups. Due to rising costs, procurement was cut back and a number of technologies developed for the NP21 program and integrated into Johann A. Revil were fitted to the existing Elementario-class design, creating the Elementario Flight IV design. Under the 2007 program restructuring, Revil-class destroyers are assigned as escorts for carriers attached to rapid deployment corps, while the Elementario-class continues to serve as the most common surface combatant in the Punic Navy. Johann A. Revil was commissioned on March 1, 2009 at the Dar-es-Salaam Navy Yard, with an additional 71 ships entering service over the next five years. The class has also been ordered by the Imperial Japanese and Gensokyo Republic navies.
- 1 History
- 2 Characteristics
- 3 Operators
- 4 See also
By 1995, the advancing age of several major warship classes in Carthaginian service had prompted the establishment of several separate development programs, ranging from nuclear submarines to aircraft carriers. The Elementario-class had been the only warship class to enter service in the 1980s following more than a decade of budget cuts and political opposition to military spending. However, the signing of the Pretoria Agreement in 1987 precipitated a shift in defense policy in the 1990s, and several projects were established to develop replacements for aging 1970s-era warships, including the Hannibal Barca-class aircraft carrier, the Sinai-class cruiser, and nearly the entire submarine fleet.
Based on the rising defense budget, it was hoped that a major fleet renewal program could be implemented. However, budget projections by the Legislative Budget Office in 1993 indicated that the current structuring of the various programs was inefficient and lacked unified oversight. The projections were especially critical of what it deemed unnecessary repetition of work developing separate components for separate designs with essentially the same function. The massive expansion of the research apparatus to support the programs had led to inefficiencies, and in 1995 the legislature ordered the Navy to integrate most of its development projects or face funding cuts. In response, all warship programs with the exception of the submarine program were rolled into the Naval Power in the 21st Century program, with the submarine projects later folded in at a later date.
Under the objectives of the program, the Navy sought to develop a series of surface combatants, amphibious assault ships, aircraft carriers, and later submarines that would replace the majority of its fleet by 2040. After a broad survey of developing technologies, it was hoped that nuclear power could be more widely used as the powerplant of the proposed fleet, extending range and reducing response times. A nuclear destroyer was also sought as a fast carrier escort, replacing the last of the Sabah Khayyam-class and eventually replacing the Elementario-class as well. The proposed destroyer had a projected displacement between 12,000-15,000 tonnes and would have full multirole capability, including the in-development SW/ETS-971 radar system.
Following the technology development phase of the NP21 program, four designs were submitted to the Bureau of Ships in 2002. Two were clean-sheet tumblehome designs while the remaining two were based on the Elementario-class hull with significant modifications. During the evaluation phase, rising program costs had made it clear that replacing nearly the entire fleet was not possible, and cost-reduction measures were implemented. This included a reduction in the expected destroyer order from 350 to 240 and later 208 units, as well as a lean away from more radical technologies and hull forms. In late 2004, it was announced that one of the Elementario-based designs, dubbed DX-04, had been selected as the winner, with final changes to be made before the laying down of the first ship in 2006. As a result of the reduced order for nuclear destroyers, a number of the technologies developed for the NP21 program were integrated into the existing Elementario-class, leading to the creation of the Flight IV variant of which an additional 90 units were ordered.
The first ship of the class, Johann A. Revil, was laid down on August 15, 2006 at the Dar-es-Salaam Navy Yard. Construction progressed on schedule and Revil was launched on February 3, 2008 for sea trials. After over a year of trials, Johann A. Revil was commissioned into the Navy on March 1, 2009. Additional ships of the class were commissioned throughout the year and class remains in production. Despite being intended to replace the Sabah Khayyam-class destroyer, retirement of the class was accelerated due to budget issues and the last of the class was retired in 2005. As a result, the Johann A. Revil and Sabah Khayyam-classes never shared a period of operational service and for four years the Elementario-class was the only active destroyer class in the Punic Navy.
The Johann A. Revil-class is 187 m (614 ft) in length and 22.5 m (74 ft) across the beam, with a draft of 9.1 m (30 ft) and a displacement of 13,800 tonnes. The hull is based on a stretched and widened variant of the Elementario-class, incorporating a significant degree of bow flare for seakeeping and an all-steel design for strength and fire resistance. The class introduced the enclosed deck design in Carthaginian service, increasing interior space and reducing radar cross section. Due to the Elementario Technology Integration Program, Flight IV Elementario-class destroyers bear a significant resemblance to Johann A. Revil-class destroyers, including a largely enclosed hull but excluding the Integrated Sensor Mast. The increased space due to the hull stretch is largely used for the engineering plant, enlarged helicopter facilities, and an increased armament.
Despite their larger size, the Johann A. Revil-class has a significantly reduced radar and infrared signature compared to the Elementario-class due to the use of an integrated sensor and communications mast in place of the older conventional masts of previous designs. The exhaust system also makes use of seawater cooling and waterline-level expulsion to limit the vessel's infrared signature even when steaming with the turbine running. In addition, the class makes use of the same hull-shaping features incorporated into later-model Elementarios, fairing over most external fittings and using inclined structures to reduce radar returns.
Powerplant and propulsion
Primary power is supplied by an IDOS Power Systems NCV4-D1 pressurized water reactor, delivering 200 MW of electricity through its accompanying generator. A separate United Nigerian PR-1100EX gas turbine is also installed to provide boost power as well as backup power in the event of a reactor accident. The reactor itself is designed to last the entire expected lifetime of the ship without refueling, allowing the ship to maintain a higher readiness state. As with other ships in the NP21 program, the Revil-class uses integrated electric propulsion, eliminating the need for propulsion gearboxes and allowing the reactor output to power the ship's electronics suite.
The Revil-class uses a pair of D6SN integrated motor-propulsors, unlike the conventional propellers of previous warships. The motor-propulsors eliminate the shaft run through the hull and reduce the vulnerability to debris while reducing the ship's acoustic signature. The twin-rudder system of the Elementario-class was retained for maneuverability, and the electric motors remove the need for reversing turbines or controllable pitch propellers. Estimated maximum speed is 34 knots, while the more common cruising speed is 22 knots. Using nuclear propulsion however the class can sustain speeds as high as 30 knots indefinitely if needed. The use of nuclear power also allows the class to operate its radar suite at full power without compromising range or speed.
Compared to previous ships including the Elementario-class, the Revil-class is designed with a higher overhead of additional electricity to support additional electronics and modernization throughout the projected lifetime of the class without the need for engine overhauls or replacements.
The Johann A. Revil-class carries the Stele combat management system, receiving data from a multitude of sources. The primary radar system is the SW/ETS-971 search and tracking radar, supported by the SW/ESH-820 hull-mounted sonar and SW/EST-822 towed array sonar.
The SW/ETS-971 X/S-band multifunction radar provides integrated 3D air and surface search capabilities through a system of four S-band and three primary X-band antennas, supplemented by additional X-band arrays on the mast. Protracted development resulted in the lower cost, lower-complexity SW/ETS-970 derivative entering service first in the Elementario-class, eliminating the additional mast-mounted transceivers in favor of the standalone X-band SW/ETS-972 radar for surface search.
The SW/ETS-971 system uses larger and higher-powered arrays than the SW/ETS-970 with additional transmit/receive modules and uses a single processing system for reduced electronics footprint and latency. The mast-mounted arrays provide dedicated surface search, gunfire control, and navigation capability while the superstructure-mounted arrays are normally used for volume search and tracking. The main X-band arrays are also used for datalink and illumination purposes when guiding anti-aircraft missile launches. The system is estimated to be capable of tracking up to 1,000 aerial targets at up to 480 km (300 mi) and up to 950 km (500 mi) against ballistic missiles.
A supplementary X-band SW/ETN-975 navigation radar is mounted on the aft superstructure above the mission deck control level. This array can also provide supplementary surface search capability.
Infrared search and track
Infrared search and track capability was included to improve detection of low-RCS targets and non-emitting targets when operating in passive mode. Two SW/ETI-848 modules are mounted, one above the bridge tower and one on the aft communications tower, providing full 360° coverage. The modules are resistant to infrared jamming and are capable of cuing missile intercepts via parallax ranging.
Sonar capability is provided by the SW/ESH-820 bow sonar and the SW/EST-822S towed array sonar. The bow installation is identical to that of Flight III and newer Elementario-class destroyers and is the standard hull sonar for Punic surface ships. The SW/ESH-820 is capable of operating in passive and active modes in the medium to low frequency range, and can act in conjunction with sonobuoys, helicopter-borne and towed array sonar to triangulate the position of enemy submarines and torpedoes. A retractable mine and obstacle avoidance segment is also included to reduce vulnerability to enemy mines and improve navigational accuracy in shallow waters.
The towed SW/EST-822S is largely identical to the SW/EST-822 on the Elementario except for the use of four rather than two transducers in the low-frequency transmitter section. It otherwise incorporates the same 400 meter receiver array and 800 meter cable. In conjunction with the bow array, the towed array can act as a bistatic sonar, or a multistatic system when networked with other vessels or aerial assets.
The Johann A. Revil-class uses the standard Mark 18 vertical launch system employed aboard other Punic surface warships. In addition to the 64 cell bow installation, a 108 cell amidships installation provides the bulk of the class' missile space. Compared to previous destroyers, the Revil-class has a larger emphasis on land attack and anti-surface missions, 28 each of cruise and anti-ship missiles compared to sixteen on the Elementario-class. Space for medium-ranged surface to air missiles was also increased. Missile guidance for anti-air intercept is normally via multiple input guidance (MIG), although land attack and anti-ship cruise missiles are normally self-guided.
Launch and guidance is handled by the Stele combat management system. Due to the class' young age, no members of the class are expected to carry the older SR-150 series of surface-to-air missiles, and the ships were designed for the SAR-77X series. The class also integrates missile defense capability against short and intermediate range ballistic missiles using the SAR-777 Madoka ABM and can provide supplementary tracking for ICBM interceptions launched from heavier warships such as the Karisimbi-class cruiser. The class also incorporates an enlarged combat information center to handle the increased data flow from the sensor suite, allowing for the more effective engagement of larger numbers of targets.
Short-range defense is provided by three 24-cell Mark 99 rolling airframe missile launchers, one mounted in front of the bridge and two amidships abeam of the communication tower. Each carries an onboard radar and short-range IRST sensor but is also tied to the ship's centralized engagement system and can be cued to fire by any of the onboard radar. The system is effective against both high-altitude and sea-skimming missiles using a dual-mode guidance system.
Each ship is armed with a single 155 mm Mark 44 rapid-fire gun mounted on the forward deck. It is capable of firing both ballistic and rocket-assisted projectiles, and uses a larger automated magazine than previous classes. The magazine can hold up to 350 rounds when fully loaded, and can load and fire the entire magazine capacity without human assistance. Rounds are loaded into the magazine in eight-round packs and the handling system can process and stow a full pack within 45 seconds. The Mark 44 has a maximum range of 44 km (27 mi) with conventional ballistic projectiles, and over 100 km (62 mi) with rocket-assisted projectiles. The normal rate of fire is ten rounds per minute. Due to gun length, the mount must be positioned to the broadside (usually to port) to use the forward vertical replenishment station.
For defense against small boats and other light surface threats the class is equipped with two 35 mm CRA-952 autocannons. Although relatively fast tracking and useful against speedboats and helicopters, the system is not fast enough for true CIWS use. This is the same type used aboard Army ground vehicles but has been modified for naval use with additional corrosion-resistance treatments. Additional small arms are stored in weapons lockers onboard for use by the crew.
Short-range torpedo capability is provided by a pair of 400 mm three-tube Mark 37 integrated torpedo launchers, concealed behind sliding panels when not needed to protect them from the elements and to reduce radar cross section. The launchers are compatible with a wide range of lightweight torpedoes, including the Carthaginian SWT-723 Blazing Star, the Japanese Type 73 and Blue Shark, and the Inuk Marks 46, 50, and 54. It is believed that the European MU90 Impact torpedo may also be fitted although software for this integration has not been developed. Torpedoes may also be deployed by helicopter or via VL-ASROC for longer-range engagements.
The class is the first to provide space for a laser weapon installation in the amidships position. The Mark 227 Seaborne Laser System was initially planned to enter service alongside the class itself but program delays prevented its introduction until late 2012. The Mark 227 has an output of 60 kW and is capable of engaging light surface targets, small drones, and some anti-ship missiles at ranges up to 12 km (7.5 mi) in clear weather. The weapon can also act as an optical detection system with a lower power setting and can be used to blind enemy optics.
New-build ships starting from DDG-836 have been commissioned with the Mark 227, and a refit program to install existing ships with the system is underway. A more powerful 100 kW system is in development and expected to enter service by 2018, improving engagement capabilities against larger and faster-moving targets.
Aviation and boat facilities
The largest improvement in capability over previous classes is in mission space for the helicopters and embarked boats. With the movement of the VLS array forward, the hangar is now a full-width structure capable of accommodating larger numbers of helicopters and their associated handling equipment as well as larger boats and unmanned vehicles. A lengthening of the flight deck also supports landing operations by larger helicopters, which can be accommodated in the enlarged hangar. The cabin was also moved and enlarged as a full level above the hangar, with additional space to house control equipment. As a result, the class can more easily support the operation of equipment such as the Giza-class USV and the remote minehunting system.
The forward vertical replenishment station of the Elementario-class was retained, increasing resupply speed or allowing the ship to conduct missions from the aft flight deck while simultaneously receiving supplies.
The Johann A. Revil-class carries a pair of SR/EWS-654 electronic warfare units mounted abeam of the bridge tower, providing passive detection and jamming capability against radar guided threats. The system can also provide targeting information based on received signals, and is tied to the ship self-defense system, allowing it to control the chaff and active decoy dispensers to counter incoming threats.
Defense against torpedoes is provided by the SR/ENS-670 towed acoustic decoy, the SDC-729 torpedo countermeasure system, and SSI-725 hardkill torpedo interceptors. The SR/ENS-670 has an integrated receiver to work in conjunction with the Warship Torpedo Defense System to detect incoming torpedoes and provides an alternative target to seduce acoustic weapons. The SDC-729 is a pneumatic countermeasure launcher that fires a spread of light depth charges allowing it to engage torpedoes regardless of seeker type, and the SSI-725 is a light hardkill interceptor torpedo designed to directly acquire and destroy hostile torpedoes and mines.
The Mark 227 Seaborne Laser System provides defense against laser and optically-guided missiles, supplemented by flare and smoke dispensers to obscure the ship from incoming missiles. With the additional space in the mission bay, the Remote Minehunting System can be more easily accommodated. Initial plans called for each ship to carry a set of RMS remotely operated underwater vehicles for minehunting purposes but this feature was removed as a cost-saving measure and a set number of systems can be installed aboard different ships as needed based on expected mission profile.
Crew and sustainment
The onboard HVAC system is capable of supporting operations in warm environments such as the tropics, as well as frigid arctic waters. The system is expanded over the arrangement used in the previous class to accommodate the greater cooling demands of the electronic equipment. The system also provides overpressure and filtration for protection against CBRN threats. To support long-duration voyages, crew spaces are enlarged and additional recreational space is provided. Food storage and preservation options are also more robust to improve morale and crew comfort relative to legacy classes.
- Punic Navy
- 108 ships active, 12 building, 178 ordered
- Punic Navy
- Gensokyo Republic
- Republic Navy
- 16 active, 4 building, 14 ordered (as Gensōkyō Millennium-class)
- Republic Navy
- Imperial Navy
- 24 active, 4 building, 26 ordered (as Kisaragi-class)
- Imperial Navy