Type-062N submarine
 SN-4100 shortly after commissioning.
| |
| Class overview | |
|---|---|
| Name: | Type-062N nuclear ballistic missile submarine |
| Builders: |
list error: <br /> list (help) Mehmud-Tabnit Oran Shipbuilders Mehmud-Tabnit Lagos Shipyards |
| Operators: |
 Carthage |
| Preceded by: | Type-053N |
| Cost: | NSD$3.5 billion (2014 prices) |
| In commission: | 9 September 2012 |
| Planned: | 144 |
| Building: | 8 |
| Completed: | 14 |
| Active: | 14 |
| General characteristics | |
| Class and type: | Type-062N nuclear ballistic missile submarine |
| Displacement: |
list error: <br /> list (help) 20,200 tonnes surfaced 25,250 tonnes submerged |
| Length: | 164.7 m (540 ft) |
| Beam: | 13.7 m (45 ft) |
| Draft: | 9.4 m (31 ft) |
| Propulsion: |
list error: <br /> list (help) 1 × IDOS Power Systems NCV4-S1 LCFR (190 MWt, 72 MWe) 1 × United Nigerian D-50 diesel-electric unit (10 MW) 2 × S7SN integrated motor-propulsor (56 MW) |
| Speed: |
list error: <br /> list (help) 35 knots maximum submerged 27 knots stealth submerged 20 knots surfaced |
| Range: | 50 year projected service life |
| Test depth: | Greater than 800 m (2,600 ft) |
| Complement: | 101 |
| Sensors and processing systems: |
list error: <br /> list (help)
PSN-1976 X-band radar PSN-1977 ESM receiver |
| Electronic warfare & decoys: |
list error: <br /> list (help) 12 × Expendable submarine acoustic decoy Mk. 41 Submarine Torpedo Defense System |
| Armament: |
list error: <br /> list (help) 8 × 660 mm torpedo tubes (Up to 50 stowed weapons) 24 × TMB-597AM2 Astarte III SLBM 1 × CRR-352 35 mm recoilless autocannon (sail) 4 × SAI-774 Sayaka SRAAM |
The Type-062N is a nuclear ballistic missile submarine class in service with the Punic Navy. The class is designed for long-term nuclear deterrence patrols, with an emphasis on stealth, survivability, and cost of operation. A member of the Type-06X series of submarines, the Type-062N is designed to replace the previous Type-053N ballistic missile submarine that currently serves as the Republic's at-sea deterrence. The Type-06X series introduces a number of significant improvements in submarine design and technology, with greater attention to cost control and reducing long-term maintenance and overhaul requirements.
Development work began in 2005 as part of the NP21 project. As a result, boats of the Type-062N class share a number of components and systems with their surface-based relatives, and most components with the Type-061N attack submarine. Construction of the first boat of the class, SN-4100, began in 2010 and the vessel was launched in late 2011, commissioning into service in late 2012. A total of 144 boats have been programmed to replace all Type-053N boats and to maintain required nuclear deterrence strength.
History
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Nuclear submarine design and development in Carthage proceeded rapidly from the 1950s through the early 1970s, leading from the initial testbed SN-1105 to the creation of the Type-045N, Type-046N, and Type-047N attack submarines and the Type-037N and Type-053N ballistic missile submarines. By 1975, the submarine force had reached a peak of 850 boats in active service, including diesel-electric submarines. Design paradigms for Carthaginian attack submarines were split between high-speed interceptors designed for coastal protection and high-stealth, long-endurance boats designed for operations closer to enemy shores. However, following the conclusion of the Northern War submarine construction slowed with the draw down in defense spending. By 1981 the submarine force had contracted to some 725 boats, and no new design had been introduced since the Type-053N.
The Type-53N entered service in 1974, shortly before the Northern War, with the intent of replacing the older Type-37N ballistic missile submarines built during the late 1950s and early 1960s. The Type-053N was designed to support the larger Astarte III ballistic missile with significantly improved range and accuracy, and carry a greater number of missiles per boat (24 versus the previous 16) to reduce crew and support costs. Improvements in quieting, sensors, and survivability were also incorporated into the design, including the first production natural circulation reactor in Punic Navy service. As a result of these changes the Type-053N displaced over twice as much as the previous Type-037N, but the increase in warheads per boat was expected to require fewer of the new submarines to be procured to meet deterrent requirements.
An initial 160 boats were expected to replace the 260 Type-037Ns that had entered service by 1974, but following the Northern War production of the Type-053N was cut to a total of 144 boats with 3,456 active missiles, down from the 4,160 missiles carried by the Type-037N series. These cuts were accompanied by a general contraction of the nuclear arsenal during the 1980s and early 1990s and a shifting of limited budgetary resources to the development of precision conventional weapons.
Notional Deterrent Submarine
While theoretical development work on new attack submarines progressed throughout the 1980s and 1990s, reductions in funding and political debate over the future of the nuclear deterrent prevented the development of additional submarine classes beyond the Type-053N. Proponents of the Kataphrakt Project of the 1980s hoped the renewed interest and funding in submarine development would allow for "trickle down" benefits for the deterrent force, but the cancellation of the program after just 48 boats in 1994 ended these hopes and left the future of the nuclear force uncertain. A potential replacement design, the Notional Deterrent Submarine, was developed by the Naval Design Bureau, but further development remained unfunded.
In 1995 following the cancellation of the Type-054N, the deterrent force received limited funding to begin design of a more conservative upgraded design, provisionally dubbed the Type-053N Advanced and similar in concept to the Type-046N Advanced project for the attack force. With a lower priority than new attack submarine development, the project had made little progress by 2005, when it and various other replacement programs were subsumed into the NP21 program.
Type-06X series
The new Type-062N was designed to have maximum commonality with the Type-061N attack submarine to reduce production and maintenance costs, remaining affordable enough to maintain the deterrent force at 144 boats. The Type-062N uses the same electronics and combat system as the Type-061N and is built using a modified Type-061N hull, with a missile compartment added amidships and a fairing on the upper hull to accommodate the additional height of the TMB-597 Astarte III missiles. Both classes share the same reactor and propulsion system, although the larger surface area and displacement of the Type-062N results in a reduced maximum speed compared to the Type-061N.
The first boat of the Type-062N class was laid down at Mehmud-Tabnit Oran Shipbuilders in May 2010, launching for sea trials in November 2011, and entering commissioned service in September 2012. The Type-062N was the last of the three new classes to be laid down and commissioned, with the first boats of the Type-060 and Type-061N classes entering service in early and mid-2011, respectively. A full 144 boats are planned to completely replace the Type-053N and maintain the deterrent force through the 2070s.
Characteristics
The Type-062N hull is 164.7 meters (540 ft) in length and 13.7 meters (45 ft) in beam, for a total displacement of 20,200 tonnes surfaced and 25,250 tonnes submerged. This represents a moderate increase in displacement over the Type-053N, largely due to increased beam and pressure hull reinforcement. The increased beam in particular allowed for the introduction of double-rafting of machinery as well as additional space to store longer towed sonar arrays for increased sensitivity. Along with other boats in the Type-06X series, the Type-062N introduces individual bunks for crew, arranged in six-bunk cabins. Given these changes, the Punic Navy has begun formally recruiting female submariners for both enlisted and officer positions.
Hull design
Externally, the Type-06X family is an evolution of previous designs. Like previous classes, it incorporates a double hull to improve hydrodynamics without impacting internal space arrangements. Great attention was focused on the bow and stern to improve hydrodynamic flow to reduce noise, improving the sensitivity of the bow sonar while underway and reducing the risk of detection. As part of this work, all protrusions and hatches forward of the torpedo tubes were removed or relocated, ensuring the smooth flow of water over the bow, while stern taper was relaxed in order to reduce turbulence around the stern. The low-profile sail introduced in the Type-061N is used with modifications to incorporate additional room for the missile compartment.
Beam was increased to partially compensate for the additional length, in order to maintain hydrodynamic efficiency. The increased beam also allows for the addition of a fifth deck and improved acoustic baffling for engine components, reducing the submarine's noise signature. Stronger structural steel used in construction also allows for the reduction in pressure vessel weight required to reach specified depths. In addition to the lengthened hull, the Type-062N is differentiated from the Type-061N by a one meter hull extension on the dorsal side to accommodate the height of the TMB-599AM2 Astarte missiles, and is smoothly faired into the low-profile sail.
Internal arrangements were much different than previous models. Whereas previous designs had used a single integrated pressure hull housed within the outer hull, new boats with the exception of the Type-060 diesel boat adopted the multi-hull solution, separating the habitable volume, reactor, and drive system into individual units. This was mandated by increased operational depth requirements, which necessitated minimizing the volume of any individual pressure vessel and allowed thanks to major improvements in the reliability of nuclear powerplants. This arrangement also increased stowage space in the inter-hull void for additional equipment, including longer towed array sonar and more advanced hydrophones. As with other members of the Type-06X series, the pressure hull is fabricated from SBY115 steel for reduced weight.
Powerplant and propulsion
Nuclear-powered classes in the Type-06X series (including the Type-062N) are powered by the IDOS Power Systems NCV-S1 lead-cooled fast reactor, producing 160 megawatts of thermal power. Although designed alongside the surface pressurized water reactors as part of the NCV4 family, the NCV4-S1 differs in that it uses more advanced variable-speed machinery and is designed to be self-cooling at low to moderate power levels via natural circulation, allowing the coolant pumps to be shut down entirely. The Type-06X series is the first class in Carthaginian service to use a lead-cooled fast reactor design, as previous classes used either a lead-bismuth reactor or more commonly, a pressurized water reactor.
Unlike previous designs, the NCV4-S1 is designed to operate on a single core throughout its expected lifetime, eliminating the need for re-coring. Although supplying roughly the same output as the Type-047N's NCV2-S3M lead-bismuth reactor, the NCV4-S1 is more compact and efficient, allowing more volume to be allocated toward other mission requirements while supplying a greater useful electrical output for onboard systems. The number of pumps and valves was minimized compared to previous designs to reduce sources of noise.
In addition to the reactor, each submarine also carries a 10 MW diesel-electric plant to supply emergency power in the event of reactor shutdown when traveling at snorkel depth or surfaced. Operation of the plant requires raising of the snorkel, but it can be used to rapidly ventilate the ship in the event of a fire or radiological accident, and provide basic maneuvering power to the propulsors. The current powerplant design, the United Nigerian D-50, is designed for rapid starting and immediate loads using an electric starter. A supplementary battery unit is also installed to bridge the gap between reactor shutdown and diesel start up, with sufficient power to operate the coolant pumps and machinery long enough to bring the submarine to the surface.
The Type-062N is propelled by a pair of S7SN integrated motor-propulsors with 3.5-meter (11 ft) propellers, attached directly to the aft hull. In addition to reductions in noise through the use of a shrouded propulsor, as a rim-driven propulsor the S7SN eliminates the need for a shaft arrangement, reducing flow disturbance and increasing flexibility of placement. Each propulsor is rated for 28 MW output, allowing the Type-062N to reach submerged speeds of up to 35 knots in spite of increased displacement over the Type-061N, while also remaining stealthy at speeds up to 27 knots.
The use of an X-form stern plane arrangement is also inherited from other members of the Type-06X family, and is designed to allow easier operation in littoral waters and shallow draft conditions. Due to the Type-062N's mission however, the class is not expected to spend any significant amount of time in such waters.
Sensors and control
The Type-06X family are equipped with the ESS-997 integrated sonar suite, composed of separate bow, sail, side, chin, and towed arrays. The Type-06X family adopts the water-backed ESA-992 bow array as a replacement for the older Mk. 53 air-backed array, reducing construction and maintenance difficulty while improving sensitivity. The current transducer design for the ESA-992 is designed to last the life of the submarine, eliminating the need for mid-life replacement. Supplementing the bow array is the ESA-994 sail array, designed to provide high-frequency coverage to supplement the bow array's mid and low-frequency coverage as well as improve navigation accuracy under ice.
The EST-995 high-frequency chin array provides more accurate seafloor mapping for maneuvering as well as greater resolution against mines and other threats. Mounted along the flanks is the ESH-993AM1 fiber-optic array, which uses fiber-optic cables wrapped around mandrels to replace the previous-generation ceramic hydrophones. The Type-062N mounts four flank arrays, one more than the standard Type-061N. The system eliminates the need for electronics and is entirely passive, reducing maintenance and manufacturing costs over legacy solutions. The EST-996 towed sonar array also incorporates fiber-optic elements, and is composed of a retractable 85-meter (279 ft) fat line and 800-meter (2,600 ft) thin line array, each attached to a 800 meter cable and released through the hull space between the propulsors.
In addition to acoustic sensors, Type-06X submarines incorporate an array of sensors designed to measure ambient conditions, including temperature, salinity, density, radiation, conductivity, and turbulence. While officially intended to allow the submarine to monitor its surroundings, a number of publications have put forth the notion that these sensors may be used for non-acoustic detection of submarines via wake tracking. These sensors are placed in a variety of locations around the hull and on the sail for full coverage around the submarine. An onboard full-tensor gravity gradiometer provides accurate navigation and positioning data to the submarine for missile launch at depths where satellite navigation signals may not be received.
For detection when surfaced or at periscope depth, the Type-06X series uses a pair of fully-digital photonics masts in place of an optical periscope, incorporating visual and infrared spectrum cameras as well as limited antennae for data transmission and reception. Additional masts provide the PSN-1976 X-band radar for surface and aerial detection, as well as the PSN-1977 ESM receiver for passive detection of electronic signals. Communication systems are designed for improved data throughput, allowing for more rapid and reliable transmission of information between the submarine and any relevant command assets.
Communications while underway can be handled via tethered buoy, incorporating basic communications equipment as well as optical, infrared, and radar sensors. This allows the submarine to survey its immediate surface surroundings as well as communicate in conventional radio bands without exposing itself to detection at periscope depth. The tethered buoy may be used at depths up to 400 meters (1,300 ft). An additional trailing antenna located in the sail may be deployed to receive communications while at shallow depths.
Control is managed through the Advanced Submarine Combat System (ASCS), relying on lighter-weight fiber-optic cables for data transmission and multifunction displays for input. Due to improved automation, manning requirements are reduced compared to legacy designs with the consolidation of several positions in the bridge, engineering, and weapons spaces.
Weapons
Like the Type-061N, the Type-062N is armed with eight 660 mm (26 in) water-ram torpedo tubes, located in line with the sail and away from the bow in keeping with previous classes. The torpedo tubes are fed by a two-deck torpedo room accommodating up to 50 weapons and with an automated handling system. The primary munitions are the SST-721 heavyweight torpedo and the SST-722 supercavitating torpedo, although boats often carry a limited number of the lightweight SWT-740 torpedo, which can be quad-packed into the 660 mm torpedo tubes through the use of an adapter. The torpedo tubes are also capable of firing other weapons, including cruise missiles and surface-to-air missiles. With the SST-721, the Type-062N has a maximum engagement range of approximately 70 kilometers (43 mi), allowing it to engage targets in adjacent convergence zones.
The primary armament of the Type-062N are twenty-four missile tubes carrying TMB-597AM2 Astarte III ballistic missiles housed in the lengthened amidships section. Each missile carries six R-102A 500 kt warheads along with 18 penetration aids for a combined total of 144 weapons per submarine. The missile tubes are identical in diameter to those carried by the Type-061N, but are one meter taller to accommodate the additional height of the missiles. Tubes are grouped in series of eight missiles, as in the Type-061N design, and the Type-062N also carries a pair of ventral launch tubes for minesweeping drones and other support devices.
For protection from air attack, a four-cell VLS mounted in the sail holds SAI-774 Sayaka IR-guided missiles in watertight canisters. For use when submerged, the canisters are released and make their way to the surface, as with other submarine-launched missiles, before scanning their field of view to detect any potential targets. When surfaced, the missiles can be launched directly from their canisters in the sail. A 35 mm autocannon is also mounted in the sail for defense against light surface threats and as a means of delivering warning shots. Equipped with supercavitating ammunition, the cannon is capable of firing underwater, but cannot be used at speeds above 8 knots when submerged.
Stealth and signature reduction
The Type-06X family incorporates advanced signature reduction technology for protection from both acoustic and electromagnetic detection. The increased hull diameter allows for moving equipment, especially engine components, to be double-rafted for improved sound absorption, and the inner pressure hull to be decoupled from the outer hull. The switch to electric drive also eliminates the need for a propeller shaft while the electric propulsors are extremely quiet, removing additional sources of noise transmission. Designed for natural circulation and equipped with variable-speed machinery, the NCV4-S1 reactor is also much quieter than previous generations and can operate at up to 40% output without pumps active.
The hull is protected by a double-layer of damping and anechoic material, composed of an inner layer designed to dampen sounds emanating from the submarine itself, and a thicker outer layer designed to absorb sonar pings and reduce the Type-062N's apparent target strength. The inner layer is approximately 30 mm (1.2 in) thick and is designed to convert vibration to heat energy, while the outer layer is approximately 100 mm (3.9 in) thick. Unlike previous installations and retrofits, the coating is applied through several spray-on layers, improving conformity to the hull shape, reducing drag noise from tile seams, and reducing the likelihood of lost coating. The exception is the bow section, which is cast as a single piece with an even greater level of precision to cover the bow sonar array.
The Type-06X family also introduces second-generation active vibration damping on Carthaginian submarines, using a series of actuators to cancel and dampen detected noise. These are controlled by a unified noise control system, which includes vibration sensors placed throughout the ship to detect and isolate sources of noise for reduction. It also allows captains to determine the effects on detectability based on their planned or desired speed. As a result of the increased displacement and wetted surface area, the Type-062N has slightly increased flow noise, but this change is considered imperceptible compared to the Type-061N.
Electronic systems are also shielded to reduce electromagnetic emissions and managed by a separate control system to maintain low-detectability. The outer hull is constructed of low magnetic steel to reduce susceptibility to magnetic anomaly detectors and other electromagnetic sensors.
Crew and sustainment
The standard complement for a Type-062N boat is 101 officers and enlisted, in three shifts. With the reduction in crew size and the increase in usable volume, crew are now housed in six-bunk cabins, allowing greater privacy and comfort during long deployments. Officers are accommodated in separate cabins, and the Type-06X series is the first to integrate mixed-gender crews. Crew amenities include increased workout space for physical conditioning, increased storage for personal items, and movie facilities in the mess deck. Additional accommodation for up to 18 mission personnel can be arranged for short term assignments.
In the event of emergency, a surfacing rescue capsule is located in the sail and can accommodate up to 90 personnel. The rescue capsule also serves as the primary point of entry through the sail. A second rescue capsule with space for 40 personnel is located in the engineering compartment and is the primary docking point for other submersibles. When carrying additional mission personnel, an additional rescue capsule may be loaded into one of the multi-purpose mission tubes. Full-body Mk. 18 escape suits are also stowed for escape in shallower waters up to 180 meters (590 ft).
Replenishment of consumables is accomplished via palletized loads introduced via a dedicated supply hatch, with additional supplies able to be loaded through the aft rescue capsule as in the Type-061N. The Type-062N is designed for rapid replenishment and maintenance to maximize time at sea, and is attended to by two crews (teal and bronze) who switch off for each deterrent patrol. Normal patrol duration is 70 to 90 days, and the use of two crews is designed to enable 2/3rds of the deterrent fleet to remain at sea.