Alexander Class CVN
| Class overview | |
|---|---|
| Name: | Alexander-class aircraft carrier |
| Builders: | Poseidon Military Maritime Industry |
| Operators: |
 Aquitayne |
| Cost: | NSD$5,000,000,000 |
| Built: | 2012-present |
| In service: | 2012-present |
| In commission: | |
| General characteristics | |
| Type: | Aircraft carrier |
| Displacement: | 101,600 tonnes |
| Length: |
337m Beam (Waterline): 41 m |
| Beam: |
12 m Beam (Flight deck): 77 m |
| Draught: | 12m |
| Draft: | 11 m (36 ft 1 inch) |
| Decks: | 20,000 square meters |
| Installed power: | 2x Kinisis 756 Nuclear Reactor 340 MW |
| Speed: | 30+ knots (56 km/h) |
| Range: | Unlimited |
| Crew: | 508 Officers, 3789 Enlisted |
| Armament: |
30× VLS modules 6 × 30 mm CIWS 4x 12 tube rolling airframe defense turrets Secondary armaments: AN/SLQ-25 Nixie Torpedo Countermeasures, MK 36 MOD 12 Decoy Launching System, AN/SLQ-39 CHAFF Buoys |
| Armor: | 64 mm Kevlar over vital spaces, steel shrapnel sheets |
| Aircraft carried: | 100 aircraft |
The Alexander Class CVN, formally the Alexander the Great Class aircraft carriers (Greek: Αεροπλανοφόρο κλάσης Μεγάλου Αλεξάνδρου) (or Alex-class) are a class of supercarrier for the Eagleland Navy, manufactured by Poseidon Military Maritime Industry, LLC, which has replaced all previous carriers in the Eagleland Navy. These new vessels use a hull design similar to the older Leonidas-Class Fleet Carrier in appearance, but many aspects of the design are different, implementing new technologies developed since the initial design of the previous class (such as the Electromagnetic Aircraft Launch System), as well as other design features intended to improve efficiency and running costs, including a reduced crew requirement. As of 2013, there are 2 Alexander the Great Class Aircraft Carriers in the Eagleland Navy.
Characteristics
A notable feature of the Alexander Class is the bridge, which incorporates five main systems; the AN/SPY-3 AESA Radar and the Tomb Stone Ladar. The latter is manufactured under licence from LG Defense Systems. The Tomb Stone Ladar can detect a missile-sized target flying at an altitude of 60 meters (200 ft) at least 40 km away, at an altitude of 100 meters at least 60 km away, and at high altitude up to 175 km away. The AN/SPY-3 is a shipboard Active Electronically Scanned Array (AESA) system. It operates in the X-band radar frequencies; X-band functionality (8 to 12 GHz frequency range) is optimal for minimizing low-altitude propagation effects, narrow beam width for best tracking accuracy, wide frequency bandwidth for effective target discrimination, and the target illumination for Anti-Air Missiles.
The X-band has, in general, favorable low-altitude propagation characteristics, which readily support the horizon search functionality of the AN/SPY-3. A large operating bandwidth is required to mitigate large propagation variations due to meteorological conditions. The system uses commercial off the shelf (COTS) computers and has reduced manning requirements for operation and maintenance. A number of operation and maintenance functions can be completely automated. It also has the capability to perform a volume search functionality. Shipboard operators will be able to optimize the SPY-3 MFR for either horizon search or volume search. While optimized for volume search, the horizon search capability is limited and vice versa.
The Ship Self-Defense System (SSDS) is a combat system specifically designed for anti-air defence of warships. It coordinates several legacy shipboard systems as well as major acquisition programs. Multi-sensor integration, parallel processing and the coordination of hardkill/softkill capabilities in an automated, doctrine-based response to the ASCM threats are the cornerstones of the SSDS. The SSDS system coordinates all the ship's existing sensors, self-defense weapons and countermeasures into a unified, distributed, open-architecture system. It provides the ship with automated and rapid-reacting anti-air defenses, aimed particularly at countering the sea-skimming anti-ship missile threat. It is largely based on commercial off-the-shelf systems. The automated integration of these sensor and weapon systems, which have traditionally been stand-alone units, greatly shortens the detect-to-engage cycle. Although SSDS does not improve the capability of individual sensors, it fuses the active and passive sensors and provides a more complete picture and enhances target automatic tracking to form a composite track.
The Alexander Class CVN utilises four Electromagnetic Aircraft Launch Systems (EMALS), utilised to launch carrier-based aircraft from catapults using a linear motor drive instead of conventional steam pistons. This technology reduces stress on airframes because they can be accelerated more gradually to takeoff speed than with steam-powered catapults. This also entails lower system weight, cost, maintenance, whilst entailing the ability to launch both heavier and lighter aircraft than conventional systems and lower requirements for fresh water, reducing the need for energy-intensive desalination. The EMALS uses a linear induction motor (LIM), which uses electric currents to generate magnetic fields that propel a carriage down a track to launch the aircraft.[2] The EMALS consists of four main elements:
The linear induction motor: It consists of a row of stator coils that have the function of a conventional motor’s armature. When energised, the motor accelerates the carriage down the track. Only the section of the coils surrounding the carriage is energized at any given time, thereby minimizing reactive losses. The EMALS' 91 m LIM will accelerate a 45,000 kg aircraft to 240 km/h. Energy storage subsystem: The induction motor requires a large amount of electric energy in just a few seconds—more than the ship's own power source can provide. The EMALS energy-storage subsystem draws power from the ship and stores it kinetically on rotors of four disk alternators. Each rotor can store more than 100 megajoules, and can be recharged within 45 seconds of a launch, faster than steam catapults. Power conversion subsystem: During launch, the power conversion subsystem releases the stored energy from the disk alternators using a cycloconverter. The cycloconverter provides a controlled rising frequency and voltage to the LIM, energizing only the small portion of stator coils that affect the launch carriage at any given moment. Control consoles: Operators control the power through a closed loop system. Hall effect sensors on the track monitor its operation, allowing the system to ensure that it provides the desired acceleration. The closed loop system allows the EMALS to maintain a constant tow force, which helps reduce the launch stresses on the plane’s airframe.
Electromagnetics are also used in the new Advanced Arresting Gear (AAG) system. The current system relies on hydraulics to slow and stop a landing aircraft. Although older models exercised a sizable amount of force on the airframe of the aircrafts that landed on it, by using electromagnetics the energy absorption is controlled by a turbo-electric engine which makes the trap smoother and reduces shock on airframes.
Also, a Plasma Arc Waste Destruction System (PAWDS) has been installed to treat all combustible solid waste generated on board the ship. A plasma torch uses an inert gas such as steam. The electrodes vary from copper or tungsten to hafnium or zirconium, along with various other alloys. A strong electric current under high voltage passes between the two electrodes as an electric arc. Pressurised inert gas is ionized passing through the plasma created by the arc. The torch's temperature ranges from 2,200 to 13,900 °C. The temperature of the plasma reaction determines the structure of the plasma and forming gas. This can be optimized to minimize ballast contents, composed of the byproducts of oxidation. At these conditions molecular dissociation can occur by breaking down molecular bonds. The resulting elemental components are in a gaseous phase. Complex molecules are separated into individual atoms. Molecular dissociation using plasma is referred to as "plasma pyrolysis."
Munitions and ammunition handling is accomplished using a highly mechanised weapons handling system (HMWHS). This is a first naval application of a common land-based warehouse system. The HMWHS moves palletised munitions from the magazines and weapon preparation areas, along track ways and via several lifts, forward and aft or port and starboard. The tracks can carry a pallet to magazines, the hangar, weapons preparation areas, and the flight deck. In a change from normal procedures the magazines are unmanned, the movement of pallets is controlled from a central location, and manpower is only required when munitions are being initially stored or prepared for use. This system speeds up delivery and reduces the size of the crew by automation.
The Alexander Class is moved by two Kinisis 756 Nuclear Reactors, capable of producing 340 Megawatts of electricity. These are molten salt reactors (MSR), which are a class of nuclear fission reactors in which the primary coolant, or even the fuel itself, is a molten salt mixture. MSRs run at higher temperatures than water-cooled reactors for higher thermodynamic efficiency, while staying at low vapor pressure. The salt mixture utilised in this instance is FLiBe, which is a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2). As a molten salt it is used as a nuclear reactor coolant having a melting point of 459°C, a boiling point of 1430°C, and a density of 1.94 g/cm3. Its heat capacity is 4540 kJ/m3, which is similar to that of water, more than four times that of sodium, and more than 200 times that of helium (at typical reactor conditions). These reactors boast a number of advantages, primarily safety and efficiency, given that the design is inherently simple. The energy produced in the Alexander Class is more than enough to power all electronic components of this design.
The ship is defended by thirty VLS modules (to be used with anti-air, anti-ship or anti-submarine missiles), nineteen Type 370 40 mm CIWS, four 12 tube Rolling Airframe Missile defence turrets, and a series of countermeasures such as the AN/SLQ-25B Nixie Torpedo Countermeasures, MK 36 MOD 12 Decoy Launching System and AN/SLQ-39 CHAFF Buoys. Decoy employment is used primarily to defend against anti-ship missiles which have avoided detection and penetrated to the terminal-defense area that represents an imminent threat to the ship.
The Type 370 Close-In Weapons System (CIWS) has been developed for the Eagleland Navy by Hyperion Defence Ltd of the Eagleland. The Type 370 CIWS entails a six-barreled 40mm Gatling gun, with a rate of fire of approximately 5,500 rounds per minute, which is linked to the GXN-990 system of the ship, whilst also including it's very own TPS-830K surveillance and fire-control radar, an electro-optical targeting system (EOTS), panoramic periscope, forward looking infrared system (FLIR), laser rangefinder (LRF), and a thermal sight. The combined targeting system of EOTS, FLIR, and LRF has a targeting range of 7 km. The TPS-830K radar can detect and track a 2 m2-RCS target from a range of 17 km.
The TPS-830K radar is an X-band (8 to 12.5 GHz) surveillance and fire-control pulse-Doppler radar, specialized for use against low-flying aircraft. Its features include real-time early warning, multiple target detection, an integral L-band (1 to 2 GHz) Identification Friend or Foe (IFF) subsystem, pulse compression, frequency agility, and adaptive moving target indication as an anti-chaff measure. It supplies ballistic computation data to the digital fire-control system to direct the aim of the electro-optical targeting system, which then aligns the 40 mm guns with the target for accurate fire. The secondary FLIR system and laser rangefinder supplements the TPS-830K radar to provide additional targeting means in case the radar is rendered inoperative, or is turned off to retain the element of surprise against aircraft that are equipped with radar warning receivers.
The Type 370 also includes four anti-air missiles, as part of it's overall system, and has a range of 4,000 metres, an ammunition storage of 3,500 rounds of ammunition (which can be reloaded through the ship's automated reloading process), a reaction time of four seconds to Mach 2 missiles, elevation −25 to +85 degrees and full 180 Degree Traverse or full 360 Degree traverse, depending on the system's location on the ship. It is an autonomous and completely automatic weapon system for short-range defense of ships against highly maneuverable missiles, aircraft and fast maneuvering surface vessels. Once activated the system automatically performs the entire process from surveillance and detection to destruction, including selection of the next priority target.
The MK 36 Super Rapid Bloom Offboard Countermeasures (SRBOC) Chaff and Decoy Launching System is a deck-mounted, mortar-type countermeasure system that may be used to launch an array of chaff cartridges against a variety of threats. The purpose of the system is to confuse hostile missile guidance and fire control systems by creating false signals. The launching system is controlled from the Combat Information Center and is dependent on information provided by the detection and threat analysis equipment on the ship.
The DLS MK 36 Mod 12 is a morter-tube launched decoy countermeasures system that projects decoys aloft at specific heights and ranges. Each DLS launcher includes six fixed-angle (elevation) tubes: four tubes set at 45 degrees and two tubes set at 60 degrees. Decoy selection and firing is controlled from either the EW console of the bridge launcher control. The DLS launches the following types of decoys: SRBOC - which uses chaff to deceive RF-emitting missiles/radars, NATO Sea Gnat - which is similar to SRBOC but with extended range and a larget payload of chaff, and TORCH - which uses heat to deceive infrarad-seeking missiles.
The Torpedo Countermeasures Transmitting Set AN/SLQ-25B, commonly referred to as Nixie, is a passive, electro-acoustic decoy system used to provide deceptive countermeasures against acoustic homing torpedoes. The AN/SLQ-25B employs an underwater acoustic projector housed in a streamlined body which is towed astern on a combination tow/signal-transfer coaxial cable. An on board generated signal is used by the towed body to produce an acoustic signal to decoy the hostile torpedo away from the ship. It also includes a fiber optic display LAN, a torpedo alertment capability and a towed array sensor. The decoy emits signals to draw a torpedo away from its intended target. The Nixie attempts to defeat a torpedo's passive sonar by emitting simulated ship noise, such as propeller and engine noise, which is more attractive than the ship to the torpedo's sensors.
Protection against electromagnetic interference and EMP attack is provided by the use of fiber optic cabling and circuitry composed of Gallium Arsenide (GaAs) where possible. Additional protections are provided by utilization of antennas and power connections with surge protectors designed specifically to defend against EMP attack and the crew area is coated with a conductive coating.
The Alexander Class CVN is built using a double-hull design. Originally used in civilian cargo ships (primarily tankers, especially after the Exxon Valdez accident in 1989), the double-hull, however expensive, serves two particular purposes; firstly, it provides additional protection from collisions, allisions and groundings; secondly, it provides room for ballast tanks and the use of Adaptiv Plates. Adaptiv is an active camouflage technology developed by BAE Systems to protect military vehicles from detection by near infrared night vision devices. It consists of an array of hexagonal Peltier plates which can be rapidly heated and cooled to form any desired image, such as of the natural background or of a non-target object. Peltier cooling plates take advantage of what is known as the Peltier effect to create a heat flux between the junction of two different types of materials. This effect is commonly used for cooling electronic components and small instruments. There are no moving parts and such a device is maintenance-free. In such a way, these plates can either conceal or mask the infrared identity of the vehicle with other objects. Adaptiv plates are placed inside the main armour, so that the process of the conduction of heat will transfer that new heat signature to the rest of the vehicle. Given that ships of this size are impossible to shield from FLIR, the Adaptiv plates provide sufficient signature reduction from FLIR detection.
Also, the shape of the hull and the superstructures is devised for the optimal reduction of the radar signature. Stealth is achieved with inclined flanks, as few vertical lines as possible, and very clean lines and superstructures: stairs and mooring equipment are internal, and prominent structures are covered by clear surfaces. The superstructures are built using radar-absorbent synthetic materials. The Alexander Class CVNs are also equipped with jammers that can generate false radar images. It's exhaust entails a heat supression system to mix hot air from the reactor with cool air from outside, further reducing thermal signatures. The usual funnel is replaced with a small sets of pipes, aft of the mast, which cool the exit gas before it is released.
The magnetic signature is reduced by the presence of a demagnetisation belt. A steel-hulled ship is like a huge floating magnet with a large magnetic field surrounding it. As the ship moves through the water, this field also moves and adds to or subtracts from the Earth's magnetic field. Because of its distortion effects on the Earth's magnetic field, the ship can act as a trigger device for magnetic sensitive ordnance or devices which are designed to detect these distortions. The degaussing system is installed aboard ship to reduce the ship's effect on the Earth's magnetic field. In order to accomplish this, the change in the Earth's field about the ship's hull is "canceled" by controlling the electric current flowing through degaussing coils wound in specific locations within the hull. This, in turn, reduces the possibility of detection by these magnetic sensitive ordnance or devices. The system used for demagnetisation includes a Main coil, an Athwartship coil and a Forecastle-Induced - Quarterdeck-Induced coil.
A Main Coil (M) compensates the induced and permanent vertical components of the ship's magnetic field (Z zone). It is installed in the horizontal plane at the waterline. As the ship changes hemispheres the coil current polarity must be manually adjusted. The Athwartship coil (A) is installed in the vertical plane and extends from the keel to the main deck. It compensates the athwartship induced and athwartship's permanent components of the ship's magnetic field. The A coil current consists of permanent and induced components. The Forecastle induced - Quarterdeck induced coils (FI-QI) are located in the same area as the FP-QP coils, they compensate for the longitudinal induced component of the ship's magnetic field. The FI-QI current is proportional to the horizontal component of the Earth's magnetic field along the ship's longitudinal axis. The FI-QI coil current is manually changed, by shifting the "H zone" switch on the switchboard, when the ship's location changes H zones. The degaussing system automatically compensates for heading changes by converting a gyro input signal to a magnetic heading.
The acoustic signature is minimized by mounting the engines on elastic supports, as to transmit as little vibrations to the hull as possible, and by rubber coating on the propellers. Finally, Vital zones are armoured in Kevlar, and important systems are redundant. The crew is protected against biological, chemical and nuclear environments. The hull has a pronounced angle at the stem, with a short forecastle that integrates directly into the superstructure. The single anchor is located exactly on the stem, into which it is completely recessed. The deck where the seamanship equipment and capstans are installed is internal in order to hide it from radar. The superstructure is built in one piece and directly integrates into the hull, with only a change in inclination. A platform is located between the main gun and the bridge.