The composition of the fleet is changing rapidly as modern ARLEIGH BURKE guided missile AEGIS destroyers enter active commissioned service. The DDG 51 was the first U.S. Navy ship designed to incorporate shaping techniques to reduce radar cross-section to reduce their detectability and likelihood of being targeted by enemy weapons and sensors. Originally designed to defend against former-Soviet aircraft, cruise missiles, and attack submarines, this higher capability ship is to be used in high-threat areas to conduct antiair, antisubmarine, antisurface, and strike operations.
DDG 51s were constructed in flights, allowing technological advances during construction. Flight II, introduced in FY 1992, incorporates improvements to the SPY radar and the Standard missile, active electronic countermeasures and communications. Flight IIA, introduced in fiscal year 1994, added a helicopter hangar and capability to embarked two multi-mission helicopters.
The initial ARLEIGH BURKE-class guided missile destroyers have a full load displacement of 8,300 tons, are 506 feet in overall length and have a 62 foot beam. They are driven by two shafts powered by four LM2500 engines. Their maximum speed is in excess of 30 knots and they have a cruising range of 4,400 n. miles at 20 knots. The ships complement is about 30 officers and 302 enlisted personnel.
All ships of this class have the AEGIS air defense system with the SPY-1D phased array radar. They are armed with a Vertical Launching System capable of storing and rapidly firing a mix of Standard, Tomahawk, and Vertically Launched ASROC (VLA) missiles for either Air Defense, Strike Warfare, or Anti-Submarine Warfare missions. Other armament includes the Harpoon anti-ship cruise missile, the 5"/54 gun with improvements that integrate it with the AEGIS weapon system, and the Phalanx Close-in Weapon System for self-defense.
The AN/SPY-1D Phased Array Radar incorporates significant advances in the detection capabilities of the AEGIS Weapons System, particularly in its resistance to enemy Electronic Counter-Measures (ECM). The AEGIS system is designed to counter all current and projected missile threats to the Navy's battle forces. A conventional, mechanically rotating radar "sees" a target when the radar beam strikes that target once during each 360 degree rotation of the antenna. A separate tracking radar is then required to engage each target. In contrast, the computer-controlled AN/SPY-1D phased array radar of the AEGIS system brings these functions together within one system. The four fixed arrays of "SPY" send out beams of electromagnetic energy in all directions simultaneously, continuously providing a search and tracking capability for hundreds of targets at the same time. Using the SPY-1D and her Mark 99 Fire Control System, these ships can guide vertically-launched Standard Missiles to intercept hostile aircraft and missiles at extended ranges. To provide point defense against hostile air targets, the ships are equipped with the Block 1 upgrade to the Phalanx Close-In-Weapons System (CIWS).
The ARLEIGH BURKE Class is also equipped with the Navy's latest ASUW Combat Systems. Land attack cruise missile capability is provided by Tomahawk Missiles, which are launched from her Mark 41 Vertical Launching System (VLS). The MK 41 VLS is a multi-warfare missile launching system capable of firing a mix of missiles against airborne and surface threats. It is modular in design, with eight modules symmetrically grouped to form a launcher magazine. The modules contain all the necessary components for launching functions when interfaced with the ship's AEGIS Weapon System. VLS is a product of Martin-Marietta. The shorter range Harpoon Anti-Ship Cruise Missiles have a range in excess of 65 nautical miles which are fired from stand-alone launchers. The 5"/54 Caliber Gun, in conjunction with the Mark 34 Gun Weapon System, is an anti-ship weapon which can also be used for close-in air contacts or to support forces ashore with Naval Gun-Fire Support (NGFS).
The AN/SQQ-89 integrated ASW Suite is the most advanced anti-submarine warfare system in the world today. The AN/SQR-19 Tactical Towed Array SONAR (TACTAS) provides extremely long-range passive detection of enemy submarines, and the AN/SQS-53C Hull-Mounted SONAR is used to actively and passively detect and locate submarine contacts. The ships also have the capability to land the SH-60B LAMPS Mark III Helicopter, which can link to the ship for support in the anti- submarine operations, as well as conducting over-the-horizon targeting missions. These systems are supplemented by the SLQ-32V(2) Electronic Warfare Suite, which includes passive detection systems and decoy countermeasures.
A new, large, waterplane area hull form significantly improves seakeeping ability. The hull form is designed to permit high speed in high sea states. The seakeeping hull form is characterized by considerable flair and a "V" shape appearance at the waterline.
The DDG-51 Class engineering plant represents an improvement in US Naval gas turbine power plant control systems. Aircraft derivative gas turbines are used for both propulsion and ship service electrical power generation. A high degree of plant automation is achieved by an interconnected system of control consoles. Four of these control consoles are located in the Central Control Station (CCS) which is the nerve center of the DDG-51 Class engineering plant.
Four General Electric LM2500 Gas Turbine Engines (GTEs) provide ship's propulsion. Each Engine Room contains two LM2500s, one propulsion reduction gear to convert the high speed, low torque output of the gas turbine engine to low speed, high torque output suitable to drive the propulsion shafting, and the related support systems and equipment. The port shaft connects 2A and 2B GTEs in Main Engine Room #2 and the starboard shaft connects 1A and 1B GTEs in Main Engine Room #1. When viewed from the stern, the port shaft rotates counterclockwise and the starboard shaft clockwise, producing outward propeller rotation. Since the GTEs cannot be reversed, the Controllable Pitch Propeller (CPP) system provides ahead and astern thrust by hydraulically positioning the pitch of the propeller blades.
Each of the three Gas Turbine Generator Sets (GTGS) is rated at 2500 KW and supplies 450 VAC, three-phase, 60 HZ power. #1 GTGS is located in Auxiliary Machinery Room #1, #2 GTGS is located in Main Engine Room #2, and #3 GTGS is located in #3 Generator Room. The GTGS are separated from each other by three watertight bulkheads for survivability. Each Gas Turbine Generator Set is comprised of an Allison 501-K34 Gas Turbine Engine, a module assembly, a reduction gear assembly, and a generator.
The DDG-51 Class ships are specifically constructed from a survivability-enhanced design that affords passive protection to personnel and vital systems. This design provides protection against underwater shock, nuclear air blasts, fragment incursions into vital spaces, radar detection, electronic countermeasures, gun and missile attacks and a Chemical, Biological and Radiological (CBR) attack. A comprehensive Collective Protection System guards against nuclear, chemical, or biological agents. The ship's damage control features and constructional design make the DDG-51 Class Destroyer the most "survivable" surface ship in the world.
In the ARLEIGH BURKE Class, all-steel construction is used. Extensive topside armor is placed around vital combat systems and machinery spaces. The bulkheads are constructed of steel from the waterline to the pilot house. The bulkheads are designed with double-spaced plate construction for fragment protection. The frontal plate causes fragments to break up and the backup plate stops the fragments from causing further damage to the interior of the ship. Other Aegis combat system equipment rooms are protected by Kevlar shielding. And, topside weight is reduced by incorporating an aluminum mast.
Acoustic, infrared, and radar signatures have been reduced, and vital shipboard systems are hardened against electromagnetic pulse and over-pressure damage. Sound isolators or "shock absorbers" have been placed on the reduction gears, giving the ship an added advantage when pursuing submarines. State-of-the-art propulsion and damage control systems are managed by an all-new data multiplexing system. Fire detectors and increased AFFF and Halon protection add to improved survivability.
During the construction of a DDG-51 destroyer, hundreds of subassemblies are built and outfitted with piping sections, ventilation ducting and other shipboard hardware. These subassemblies are joined to form dozens of assemblies, which were then joined to form the ship's hull. During the assembly integration process, the ship is outfitted with larger equipment items, such as electrical panels, propulsion equipment, and generators. The ship's superstructure, or "deckhouse," is lifted atop the ship's midsection early in the assembly process, facilitating the early activation of electrical and electronic equipment. When the ship's hull integration was complete, the ship is moved over land via wheel-on-rail transfer system, and onto the shipyard's launch and recovery drydock.
Class changes in production Flight IIA critical to littoral warfighting effectiveness include the incorporation of embarked helicopters (SH-60B/R), an organic minehunting capability and the introduction of area theater ballistic missile defense capability to protect near coastal airfields and seaports essential to the flow of forces into theater in time of conflict.
The first 28 Arleigh Burke-class destroyers have a helicopter deck but no hangar or embarked helicopters. Ships in production Flight IIA also have landing and hangar facilities for operation of two multi-purpose Light Airborne Multipurpose System LAMPS MK III helicopters. This capability will be added for the remaining 29 ships of the class. The modifications require removal of Harpoon missile capability. The addition of a helicopter hangar, the introduction of SPY-1D(V) radars and the upgraded baseline 6.1/6.3 and now baseline 7 Phase 1 AEGIS Combat System are three of the most significant upgrades. Also beginning with this ship, the number of VLS cells will be increased from 90 to 96, and the Phalanx close-in weapon system will be joined by vertical-launched the North Atlantic Treaty Organization (NATO) Evolved Sea Sparrow missiles when they become available.
The construction of the helicopter hangar is the most visible change for this new generation of AEGIS Destroyers. Located aft of the after Vertical Launching System (VLS), the hangar will be large enough to accommodate 2 SH-60B/R helicopters, support equipment, repair shops and store rooms. Modifications were also made for additional crew required for a helicopter detachment to deploy with the ship. As a result of the increased elevation of the after section of the ship, the aft facing AN/SPY-1D arrays were raised 8 feet to provide visibility over the hangar.
The ship's Recovery, Assist, Securing, and Traversing (RAST) system is utilized to move the helicopter into and out of the port and starboard hangars. Helicopter facilities including the following: dual hangars with bridge cranes and Navy standard helo hangar doors, Helo Control Station, RAST Control Station, Torpedo, Missile and Rocket Magazine with bridge crane and weapons hoist, Landing and Helo In-Flight Refueling (HIFR) facilities for LAMPS MK III SH-60B helicopters. VLA lighting, Stabilized Glide Slope Indicator (SGSI)/ Wave-Off Light System WOLS) and Horizon-reference set are included.
The Navy will begin deployment of the remote minehunting vehicle system on a select number of Arleigh Burke class Flight IIA destroyers beginning in 2005. One of the greatest threats to today’s naval battlegroup is mines. In fact, of the 18 U.S. Navy ships destroyed or damaged in conflicts since 1950, mines caused no fewer than 14 of those casualties. To give the modern battlegroup the optimum chance of survival in hostile "brown water" regions, the Program Executive Office for Mine & Undersea Warfare (PEO MIW) began the development of an organic mine-hunting capability to be carried aboard the Navy’s Aegis destroyers. These ships are traditionally among the first surface combatants to enter the littorals ahead of a battlegroup. Once launched from the host ship, the vehicle deploys to detect, localize, classify and identify moored and bottom mines in deep and shallow water. The 23-foot long vehicle searches for the mines under the surface of the water. A streamlined combination snorkel and antenna mast, which draws air to the vehicle’s diesel engine, will be its only visible feature above the surface. The remote minehunting vehicle can search for mines autonomously along a pre-programmed track, or can be controlled manually in real-time from the host ship by a single operator. All control and display functions will be integrated with the ship’s AN/SQQ-89 undersea warfare combat system, with mine contact data linked to the Aegis combat system.
The DDG 51 baseline upgrade plan incrementally improves DDG 51 systems in a time phased manner. Later hulls of the Flight IIA DDGs have NFCS, Link 16, and Cooperative Engagement Capability. the evolving fit of advanced combat systems capabilities and spirally developed improvements mark the path of the evolution of the highly successful ARLEIGH BURKE class destroyer design to meet the rapidly expanding littoral warfighting missions.