Dadao-class [DO NOT POST]

[Pharthan]

Go To Halcyon Arms Storefront For Purchase
Collaboration between Lamoni and Pharthan

DADAO-CLASS
GUIDED MISSILE / BALLISTIC MISSILE SUBMARINE

High Resolution Image
RESTRICTION LEVEL FOUR
Unit Cost:$25 Billion
DPR Cost: $25 Trillion
*LIMIT: 20 PER PURCHASE

Stats:
Displacement: 87,000 tonnes submerged
Length: 271.27 m
Beam: 29.87 m
Draught: 19.81 m
Depth: 400 m
Propulsion:
- 2x S6H1 Pressurized Water Nuclear Reactor = 620 MW total
- 1x IEPS electric motor = 90 MW
- 2x Emergency diesel generators = 2.6 MW total
- 1x Integrated Electric Power System, with pump-jet propulsor
Speed:
- 20 knots surfaced
- 30 knots submerged
- 20 knots "silent"
Range: Unlimited
Endurance: Limited only by food and maintenance (~120 days)
Complement:
- 20 officers
- 164 crew
- 12 special forces commandos

Hull:
- HY-100 steel
- Amitto polymer
- Anechoic tile

Electronics:
- Observation/attack optronics mast (EO/FLIR, HRR InGaAs laser diode pumped, Er:Glass laser rangefinder)
- L-Cube Integrated Sonar System
- Xiphias X-band FMCW, LPI navigation radar (44 km range)
- Ka-band SATCOM
- Underwater communications wire
- ELF, VLF, LF, HF, VHF, UHF radios
- IFF system
- GPS navigation system
- Inertial navigation system
- Equitatus Integrated Combat System

Electronic warfare and decoys:
- ESM system
- COMINT system
- Umbro countermeasures suite (32 Torfector decoys)

Emergency Systems:
- RESUS (solid-fuel) gas generators
- Emergency dual High Frequency/Low Frequency Sonar Beacon
- Emergency Position Indicating Radio Beacon
- Submarine Escape Immersion Equipment Mk. X

Armament:
- 6x 533 mm torpedo tubes (40 weapons or 80 mines)
- 36x VLS cells (fits LY4046 Dawnbringer SLBMs, SAMs, cruise missiles, UCAVs, AUVs, special forces equipment storage, etc) [/list]

Construction & Stealth
Power & Propulsion
Integrated Combat System
Communications
Sensors
Navigation
Armament
Countermeasures
Crew Services & Amenities

DESCRIPTION

As part of a partnership between LAIX ARMS and Halcyon Arms, the two companies decided to take a look at the Kraken class SSGN, and Triton class SSBN, their design, and what could be done to take these two designs into the future. LAIX ARMS suggested that with modern advances in weaponry and electronics, the two classes could be merged into one class, with but a modular change in armament.

For LAIX ARMS purposes, the resulting design would be called the Dadao class, complementing the latest SSN and SSK designs completed by LAIX ARMS. For Halcyon Arms, the joint design would result in a simplification of their manufacturing processes, saving them time in building the resulting submarines, while increasing profit, and overall design reliability.

Warfare Roles of the Dadao

• Attack Submarine
• Ballistic Missile Defense
• Nuclear MAD Deterrence Ballistic Missile Submarin
• Satellite Launch Platform
• Reconaissance
• Electronic Warfare
• Strike Submarine
• Anti-Surface Warfare

Go To Halcyon Arms Storefront For Purchase

[Pharthan]

Construction & Stealth
Write-up by Lamoni

The hull of the Dadao class is constructed of HY-100 steel, which helps contribute to the submarine's deep crush depth of four hundred meters. It should be stated that the submarine should exercise extreme care any time that it is anywhere near this depth, as the pressure at that depth can crush the entire submarine as if it were an empty beer can, killing all aboard. The strength of the HY-100 hull is further increased through the use of ribbing and compartmentalization, as a submarine hull undergoes deformation with changes in pressure, and the hull must be able to withstand repeated deformation cycles.

The Dadao class also uses multiple methods and technologies in order to assist with acoustic stealth. Anechoic tiles are the first method. Anechoic tiles are rubber or synthetic polymer tiles containing thousands of tiny voids, applied to the outer hulls of military ships and submarines via adhesive.

Their function is twofold:

1. 1.) To absorb the sound waves of active sonar, reducing and distorting the return signal, thereby reducing its effective range.
2. 2.) To attenuate the sounds emitted from the vessel, typically its engines, to reduce the range at which it can be detected by passive sonar.

The synthetic polymer tiles used on the Dadao class are 600 mm by 300 mm by 85 mm, and mass in at 31 kilograms.

Secondly, while not part of the submarine's hull per se, the submarine also incorporates a method for improving the acoustic impedance of Epoxy Resins. The process used has succeeded in producing a castable and high modulus acoustic dampening material, which absorbs acoustic energy.

Relative to soft rubbers and the like previously used for acoustic damping, the polymer (called “Amitto”) has a high modulus of elasticity; that is, Amitto is stiffer and, therefore, better suited for applications in which some stiffness is required. One prior acoustic-dumping material contains lead, and is produced by casting into blocks that must then be machined to desired sizes and shapes. The release of lead particles during machining poses a toxicity hazard. In contrast, Amitto has little toxicity and can be cast in molds to final sizes and shapes, without machining.

It is not been possible to obtain a desired combination of high modulus of elasticity (E) and high damping in a rubber or a similar single-component material for the following reasons:

1. 1.) A rubber or similar material typically undergoes a glass-to-rubber transition in a temperature range characterized by a middle temperature Tg (denoted the glass-transition temperature). It is well established that such a material dissipates vibrations more effectively at Tg than at higher or lower temperature but also tends to be relatively soft (to have low E) at Tg. A rubber or similar material typically undergoes a glass-to-rubber transition in a temperature range characterized by a middle temperature Tg (denoted the glass-transition temperature). It is well established that such a material dissipates vibrations more effectively at Tg than at higher or lower temperature but also tends to be relatively soft (to have low E) at Tg.
   
2. 2.) It is also well established that the rate at which acoustic energy enters the material is proportional to E1/2. Hence, if a material has low E, it may not absorb acoustic energy at a rate high enough to be considered an efficient damper, even at Tg.

While it is currently not possible for a single component material to possess high dampening ability, as well as a high value of E, it is possible for a two component material to do this. A higher-damping, lower modulus component is dispersed within a lower-damping, higher-modulus component. This principle underlies Amitto, in which two-component materials are synthesized following a phase-segregation approach common to that followed in synthesis of rubber toughened epoxy materials.

In Amitto, the higher-damping, lower-modulus component is a carboxy-terminated butadiene nitrile (CTBN) formulated to have a Tg at or near the intended use temperature, and the lower-damping, higher-modulus component is an epoxy. In the first step of the synthesis of the material, a CTBN or a suitable mixture of CTBNs is mixed into an epoxy resin (typically in a proportion of 1 to 3 parts of CTBN to 10 parts of epoxy by weight or volume) at a temperature of about 150°C.

Once the epoxy resin has become modified by reaction with the CTBN, it is cooled, and then mixed with the epoxy-curing agent (2-ethyl-4-methylimidazole). The curing reaction involves both cross-linking and gelling of the resin molecules. During the curing reaction, the CTBN component becomes segregated into a separate phase comprising discrete, approximately spherical rubbery domains, between 1 and 10 μm in diameter, dispersed throughout the epoxy resin. Because most of the volume of the material is occupied by the relatively high-modulus epoxy and the Tg of the rubbery domains occupying part of the volume is at or near the intended use temperature, the material can have the desired combination of sufficient stiffness and sufficient damping.

The amount of rubber added to the epoxy is low enough that the modulus of the resulting composite does not vary much from the unmodified and high modulus epoxy resin. This high modulus allows a larger amount of acoustic energy to enter the material, where it is absorbed by the rubbery component. The resultant material is non-brittle and when cast in place the material exhibits adhesion to many surfaces.

The resulting polymer is situated between the chassis, and three centimeter thick panels of Aermet 100, contained inside the bulkheads surrounding the various compartments of the submarine.

Thirdly, machinery inside of the submarine is made further quiet via a process known as 'rafting,' in which the machinery is attached to rafts of synthetic polymer and metal, which serves to reduce machinery vibrations to the hull, and thus radiated noise.

The submarine uses a pump-jet propulsor, which further quiets the submarine by reducing tip vortices, as well as reducing cavitation. Even with the pump-jet propulsor installed the submarine will always be quieter at slower speeds. While not part of the stealth measures of the submarine, the Xiphos uses computer controlled X-rudder configuration, allowing the submarine enhanced maneuverability in both shallow and deep waters, as well as the ability to hover closer to the sea floor when required.

The bow and stern planes, which project out to the sides of the boat, are used to "fly" the boat through the water. By varying the angle on these planes the boat may be made to rise, fall, or remain at the same depth as it moves forward. Since the boat is normally trimmed to be slightly positively buoyant, the planes are used to hold it down. This is a safety feature, because if all power is lost it is normally preferable to slowly rise to the surface and not to sink.

Finally, a degaussing procedure is used to reduce the magnetic signature of the submarine. A sea-going metal-hulled ship or submarine, by its very nature, develops a magnetic signature as it travels, due to a magneto-mechanical interaction with Earth's magnetic field. This signature can be exploited by magnetic mines, or facilitate the detection of a submarine by ships or aircraft with magnetic anomaly detection (MAD) equipment. Navies use the deperming procedure, in conjunction with degaussing, as a countermeasure against this.

Specialized deperming facilities are used to perform the procedure. Heavy gauge copper cables encircle the hull and superstructure of the vessel, and very high electrical currents (as high as 4000 amperes) are pulsed through the cables. This has the effect of "resetting" the ship's magnetic signature. It is also possible to assign a specific signature that is best suited to the particular area of the world in which the ship will operate. But over time, the deperm will begin to degrade, and the procedure must be redone periodically to maintain the desired effect.

The Dadao has a displacement of 87,000.00 tonnes while submerged. The main ballast tanks of the submarine help allow it to surface or dive. In addition to the main ballast tanks, which are normally kept either empty or completely full, there are also several variable ballast tanks inside the pressure hull. These include bow and stern buoyancy tanks, various trim tanks, and the negative and safety tanks.

The sail has been hardened, so that the submarine may punch through arctic ice, if the need arises.

A specially designed dry-dock shelter for Swimmer Delivery Vehicles can be installed over the submarine's aft escape trunk, allowing the submarine to remain farther offshore while still being able to deliver special forces commandos to and from the beach. The aft escape trunk is also compatible with Submarine Rescue Vehicles, which offers a capability to remove the crew from the submarine if the submarine becomes disabled. Six people can be processed through the aft escape trunk at a time, due to space constraints.

Aft of the reactor compartment is a special escape trunk, which can accept objects up to the size of 463L master pallets, allowing the Dadao class to be restocked with food and other supplies via helicopter delivery, if desired. The capability can be used to extend deterrent patrols, airlift human casualties off of the submarine, or to increase the number of people that can escape the submarine, should the submarine be in an emergency situation in which this would be required.

[Pharthan]

Power & Propulsion
Write-up by Pharthan and Lamoni

The Dadao class uses two S6H1 Pressurized Water Nuclear Reactor Plants to provide power for the submarine via a nuclear powered Integrated Electric Power System, which uses electrical power from the Pressurized Water Reactors in order to both provide propulsive power to the pump-jet propulsor, as well as providing electrical power to all of the other systems onboard the submarine.

S6H1 Stands for:

S: Submarine platform
6: Contractors sixth design generation
H: Halcyon Arms. Contracted Designer
1: First iteration of the present Reactor Design

The S6H1 is a Pressurized Water Reactor utilizing nuclear fission for the purpose of heat production to be used to create steam for usable work. The S6H1 is jointly designed and built by Halcyon Arms, LAIX ARMS, and Asimov Engineering. Core life is expected to be twenty years, depending on operations, maintenance, and modifications made. Utilized for only electrical power, the core may last for up to 60 years. The reactor core is rated to 310 MW production capacity and utilizes highly enriched uranium as fuel. The Uranium is made into uranium oxide pellets which are then clad in zircaloy to make fuel-plates, which are stacked with gaps between them (for coolant to pass through), and made into assemblies, which are then assembled around a center channel design for the control rod to pass through, making a fuel assembly. This fuel assembly is immobile within the core.

A scaled up version of previous designs, the S6H1 is a two-loop reactor plant design, using highly pressurized and purified water as both coolant and moderator. The heated coolant passes through a boiler unit, heating it's water to produce steam. This water is then pumped back to the core by a reactor coolant pump, one per loop, where it passes around the reactor vessel, mixing with water from the other loop and then through a colander to ensure proper mixing of the coolant and filtration of debris, should any exist. From the colander the water passes up through the first-pass fuel channels for the initial heating, then out, around, and down the fuel assemblies to again pass upwards through the second-pass fuel channels, heating up the coolant further before ejecting it into the outlet region, where the coolant is sent back through towards the boiler units. All water which passes through the reactor and it's coolant loops are referred to as "The Primary," with all water that passes through the steam plant referred to as "The secondary."

The boilers provide steam for three turbine generators, one of which is used to power the reactor coolant pumps and assist with propulsion, and the other two powering the Common Electrical Distribution System, though they may provide power for the reactor coolant pumps. The steam, once passing through all systems, directly condenses into water in condensers and is pumped back to the boiler units.

The secondary water never comes into contact with primary water, and is kept at much lower pressures, allowing for it to boil when achieving the same temperature as the primary. The primary water is kept far below saturation temperature for the pressure it attains, and uses a pressurizer as a surge volume for it's water.

The S6H1 utilizes All-Electric Propulsion. Instead of main engines driving a shaft with separate turbines generating power for the ship's electric plant, all major steam-driven turbines provide electrical power. This power is then transmitted as needed around the ship, with the majority, especially in transit or combat, going to the pump-jet propulsor. This eliminates the large, heavy shaft and it's bearings, much of the lubrication oil system, and the massive and expensive reduction gears.

Overall, this makes the entire power plant smaller, cheaper, and easier to manage and maintain. The bearings on turbines are electromagnetic, reducing friction.
Due to using water as a coolant/moderator, the reactor achieves natural stability. If the reactor experiences an up-power transient, when the coolant heats up further it will be less dense and moderate fewer neutrons, so more neutrons will escape the core, again lowering reactor power back to it's original state. The only process, therefore, which will change reactor power and maintain it steady-state at that new power is a change in steam-demand, save for massive introductions of poisons which drive the reactor out of it's power range, such as a protective "Scram".

Conversely, other factors can change temperature, namely the introduction of poisons, to include control rods. Silver-indium-cadmium alloy (80% Ag, 15% In, 5% Cd) control rods are used for reactor control as well as protection; in the event of a loss of power they will automatically scram (insert to the bottom of the core, shutting it down completely). This can also be done by the operator or by automatic action in the event of other casualties as well. Additional safety features include automatic filling of the reactor, should the core become depressurized and risk becoming uncovered, which would mean a lack of coolant and would allow for potential meltdown. With this, significant release of fission-product contamination external to the hull of the ship is guarded against.

The S6H1 is capable of operating at up to 10% power without powering it's reactor coolant pumps; this natural circulation can be used for both decay heat removal and low power operations, making the reactor plant relatively quiet, but this natural circulation also provides for power transient-response and is not suitable for combat operations. As they are easy to cool without operator action or electrical power, the S6H1 reactor design is remarkably safe when shutdown. This also means that the reactor plant can perform a battery-only start-up, which is highly valuable for combat scenarios or a loss of all reactor plants simultaneously. The S6H1 also utilizes an Emergency Core Cooling system, which pipes primary-system water via a thermal driving head to heat exchangers that use seawater. Like others, this system requires no power and initiates automatically.

Radiation shielding is required and makes up the outside of the reactor compartment, which houses the reactor, boiler units, coolant loops, reactor coolant pumps, pressurizer, and filtration system. The shielding is made up of borated polyethylene, water tanks, steel, and lead. It also has photovoltaic cells lining the inner wall to provide a trickle-flow of electricity to power the ship's battery and auxiliary reactor-plant batteries. With the reactor at power this trickle flow can be used to maintain a supply of electricity to critical components. Entering this reactor compartment while the reactor is at power is considered to be deadly, but the layered shielding is so sufficient that personnel working in the propulsion plant will receive less radiation than those working on the weatherdecks of the vessel.

In the event of a loss of power, emergency diesel generators can provide auxiliary power. They are primarily designed to support the reactor plant's automatic fill protection system, but they can also be aligned to the common electrical distribution system for propulsion or other power needs.

In the Dadao class, the dual-reactor plant starts aft of the center of the ship and takes up the majority of the aft end of the boat. Boilers are placed centerline, where they may sit higher, and the reactors, which share a reactor compartment for size concerns, sit on either side of the boiler units. The boilers are placed higher to aid natural circulation. Auxiliary reactor systems required to be maintained in the reactor compartment must be shielded along with the reactors.

[Pharthan]

Integrated Combat System
Write-up by Lamoni

The key words for modern nuclear and diesel submarines comprise: International Operations, Interoperability with other naval units, ISTAR (Intelligence, Surveillance, Target Acquisition, Reconnaissance), and Network Enabled Capabilities. To do the job, submarine command teams need a system that can deal with the massive volume of data that is produced by the submarine's more and more sophisticated sensors and systems, while displaying the vital data most needed by the command team.

The Equitatus Integrated Combat System is designed specifically for this. It is based on a fully distributed, easily-upgradeable open computer architecture, laid out around a high-bandwidth data bus and employing state of the art software. The standardized multi-function operator consoles, equipped with the latest flat-screen LCD displays, offer a very user-friendly human-computer interface.

The system typically comprises three to five Multi-Function Consoles. This number can easily be adjusted upwards or downwards, for example to meet the customer's operational concept or to fit the available space.

The Equitatus system includes the following functions:

• Application functions: sensor integration, sensor administration and control, contact/target correlation, target motion analysis, classification, and identification.
• Decision support and advisory functions: threat evaluation and engagement analysis.
• Weapon functions: torpedo preparation, firing, and control, as well as missile preparation and firing, mine functions, and torpedo countermeasure functions.
• Utility functions: data recording, data replay, embedded simulation, system administration, and integrated communications.

The basic design philosophy of the Equitatus system has resulted in a solution with the following main features:

• Distributed data processing, based on a number of powerful, general purpose COTS computers
• Data communication between the Equitatus subsystems, sensors, and effectors is handled by a LAN (Gigabit Ethernet), or point to point connections
• Built-in redundancy and graceful degradation provide a high system availability (important to achieve long endurance at sea, also because the system can be operated by a single person during reduced states of readiness)

To support such mandatory tasks as Target Motion Analysis, target classification, threat evaluation, and weapon control, Equitatus provides the following functionalities:

• Generation of high quality target solutions based on available sensor data and other information sources
• Exploitation and fusion of available sensor data to provide target classification and identification
• Presentation of target solutions and other tactical data to the command team
• Exploitation of these data for the deployment of weapons and other effectors

Further, the system allows for instant messenger style communications between various compartments of the submarine, a feature which can be especially useful when the submarine is in ultra-quiet conditions. Equitatus is fully capable of targeting and firing torpedos, anti-shipping missiles, and even cruise missiles, and manages sensor data, including sensor data fusion, allowing for faster target classification and identification.

The Equitatus Integrated Combat System acts as a force multiplier, which helps to increase the tempo of submarine operations, as well as being easy to maintain due to the system's open architecture, and use of COTS components. The system software is structured in functional units, making the software just as modular as the system's hardware, and a delight for submariners to use in the performance of their duties.

[Pharthan]

Communications
Write-up by Lamoni

The first part of the communications suite of the Dadao class is a Ka-band SATCOM communications system. This allows for communications between higher command and the submarine, no matter where in the world that the submarine is.

Communications Management Software has been installed onboard the submarine, providing economical, efficient, and effective routing of messages across multiple communications frequencies both within and without the submarine. When combined with the submarine's Integrated Combat Management System, the communications management software also allows for instant messenger style communications between compartments within the submarine. This feature does not involve sound, and can be used even in ultra-quiet conditions.

A floating wire communications device allows the submarine to receive communications in the 2 MHz to 35 MHz range while the submarine is at depths of up to 125 meters from the surface. Reeling and unreeling of the floating wire can be performed at depths of up to 400 meters. This measure gives the submarine the ability to remain stealthy while receiving important communications, even in enemy patrolled waters.

A Digital Modular Radio has been installed in the Dadao, with a frequency range of from 2 MHz to 2 GHz. When combined with the installed communications management software, the Digital Modular Radio provides a single point of control for communications in the maritime HF, VHF, and UHF radio bands. Two crossed loop type antennas are present on the Dadao, allowing the communications system to pick up and transmit in the VLF/LF bands. On exported Dadao class submarines, the communications encryption computer has been erased, so that export customers can provide their own encryption protocols for all communications.

Expendable UHF radio buoys can be launched from the submarine as well. These radio buoys can be pre-programmed with a desired message before being launched from the submarine. Once launched, the radio buoy ascends to the surface, where it will begin transmitting the pre-programmed message in the UHF band a total of four times before scuttling itself, thus not allowing the enemy evidence that the submarine was even in the area.

An ELF receiver has also been installed, allowing for the purchasing nation to be able to contact their submarines while they are at depth. Since ELF transmissions have a very low data rate, these transmissions are generally short, rarely consisting of more than a short alphanumeric code bloc that tells the submarine to reach periscope depth for the reception of further communications using higher data rate radio frequencies.

Tied in with the MOAS sonar, the Dadao class implements an underwater telephone. Using high frequency acoustic transmissions, the underwater telephone provides the ability to communicate with other submarines without having to come near the surface. Users of this system should be advised that it is possible for nearby enemy units to be able to track the acoustic transmissions, and therefore use of the system should only occur when needed, and once it has been determined that the area is clear of nearby enemy units.

An IFF system has also been installed, which tells friendly units and weapons that the submarine is another friendly unit, and should not be attacked or fired upon. The system is meant to help prevent blue on blue friendly fire situations, as well as helping to improve the tactical picture for all friendly units.

The communications suite of the Dadao class also enables it to be a small but powerful forward command post for special operations forces, while being deniable due to the stealth inherent in modern submarines.

[Pharthan]

Sensors
Write-up by Lamoni

The L-Cube integrated sonar system is designed to provide a safety bubble around the submarine by providing three-hundred sixty degree sonar coverage out to hundreds of kilometers away from the submarine. Information from each of the sonar sensors is integrated onto the master waterfall displays on the sonar operators multi-function consoles, allowing the Dadao class to detect targets, detect threats such as torpedos, as well as helping the submarine to navigate. The processing power of the system is said to be equivalent to 60,000 home PCs, which translates to vastly improved detection and beam-forming algorithms.

The bow mounted low-frequency active/passive sonar system eschews the spherical sonar array systems of previous SSN classes, and instead opts for a parabolic shaped bow mounted conformal sonar array. This design increases the amount of space in the forward spaces of the submarine, while not degrading sonar performance. The choice of a low frequency array was made in order to increase the distance under which contacts could be detected, though like all sonar systems, detection distance (and therefore sonar performance) is also heavily affected by external environmental and sound propagation conditions.

A high frequency passive intercept sonar array has also been fitted to the Dadao. This system detects active sonar from other ships and submarines, calculating the distance, bearing, and elevation to the source of the noise being tracked, thus assisting the other sonar arrays onboard the submarine.

The submarine's polyvinylidene diflouride (PVDF) sensor based planar flank arrays are modular in construction, the length being determined by the length of the submarine. Rather than using three sonar panels per side as in standard Wide Aperture Array sonar systems, the Dadao class submarine's low frequency planar flank arrays can fulfill all functions of a Wide Aperture Array with one longer sonar array on each side of the submarine. Adaptive beam-forming allows for greater resistance against both own-noise and flow noise, which further increases detection and classification performances, even at high speed. Excellent bearing resolution/discrimination features enable improved Target Motion Analysis capabilities. Each planar flank array provides sonar coverage over 165 degrees, overlapping the sonar coverage from other sonar devices onboard.

A fully reelable passive, thin-line, low frequency towed array sonar has also been fitted to the Dadao, allowing the submarine to detect contacts at long range, even when the submarine is moving at high speed. The towed array sonar can operate at depths of up to 800 meters, which is deeper than the submarine can operate, and can be placed above or below any nearby thermoclines, reducing the chance that enemies can use the thermocline to ambush the submarine. The towed array sonar can be reeled back into a storage compartment in the submarine when it is not needed, or when the water depth is too shallow to permit use of the towed array.

The Dadao is fit with a passive own-noise hydrophone system, which can assist with stealth by giving the commanding officer a good idea of how noisy or quiet that his/her submarine is. Moving at high speed will increase the amount of noise generated by any submarine, as will any other activity which generates noise. This noise will enable other ships and submarines to detect the source of the noise on passive sonar, compromising stealth.

The Mine and Obstacle Avoidance Sonar is a combined three dimensional high frequency/low frequency active sonar which is meant to provide safe navigation in hazardous areas. The MOAS system is divided into separate transmitting and receiving transducers, which can be shaped to fit into any available space in the submarine's bow that is large enough to accommodate them, thus reducing flow noise. The MOAS's active sonar signals can provide three dimensional sonar data from ranges between 100 meters to 3,000 meters, and the range can be set by the sonar operator to fit any tactical need, including mapping the ocean bottom.

The Dadao has four small high frequency active sonar panels on the sail. These are used for under-ice sonar, allowing the submarine to determine the thickness of the ice above it, helping it to find a place where the submarine can surface through the ice, if required. Meanwhile, an echosounder system determines the depth to the ocean bottom from the ship's keel. The information generated can be useful in determining the overall tactical situation.

A pair of optronics masts have also been fitted to the Dadao. Unlike more traditional periscopes, optronics masts, do not penetrate a submarine's pressure hull, and can transmit the images they capture to a large screen television in the submarine's control room, which no longer has to be directly under the submarine's sail. These optronics masts make use of electro-optical, imaging infra-red, and low-light level television channels in order to gain a clear picture of conditions on the surface, and also help with submarine navigation when entering or leaving port. The optronics masts also feature an eye-safe High Repetition Rate InGaAs laser diode pumped, Er:Glass laser rangefinder as an option for determining the range to objects on or above the surface.

Sitting on top of one of the optronics masts is the ESM/ELINT sensor, which can detect and locate electronic emissions in a frequency range from 0.6 to 40 GHz, using phase and amplitude direction finding methods to determine the bearing and distance to the specified electronic emission with an accuracy of under two degrees of bearing. ESM/ELINT signals are compared against a database of previously detected electronic emissions, in order to determine if the electronic emission in question can be identified. New electronic emissions can also be uploaded from the submarine's ESM/ELINT library to other ships or shore facilities, or they can be downloaded to the submarine from other ships, aircraft, or shore facilities.

On top of the other optronics mast is the SIGINT/COMINT sensor. The system is dedicated to tactical reconnaissance in surveillance, early warning, and communications intelligence (COMINT). It fully integrates wide band interception, direction finding, signal processing, and analysis for the complete HF and UHF frequency range (100 KHz to 3 GHz). The ESM mode focuses on the automated detection, acquisition, classification, and tracking of emitters to generate information for the commander on duty. In COMINT mode one, the system is focused on the manual search and detection of signals - interception, analysis, recording, and processing is provided. COMINT mode two supports remote controlled operation as a sensor platform. The antenna system is supported by a water-cooled, ruggedized electronic computer system, which can assist in the detection, logging, recording, and decoding of intercepted communications.

[Pharthan]

Navigation
Write-up by Lamoni

The two primary electronic navigation tools onboard the Dadao class are a Global Positioning System receiver, as well as an Inertial Navigation System. While inertial drift is common to all INS units over time, the unit onboard the Kukri has the low inertial drift of 1.85 kilometers per twenty-four hours. INS drift can be corrected by taking GPS fixes, but this involves the submarine going to periscope depth, and so might not always be tactically advisable.

The Dadao class also has an X-band Frequency Modulated Continuous Wave, Low Probability of Intercept navigational radar. The radar is less likely to be detected by enemy ESM, and can also be used to gather short range targeting information on enemy surface units and low-flying aircraft. However, while the likelihood of the enemy detecting the radar is low, it is highly suggested that the operator only use the radar when entering or leaving port. The radar has a range of 44 kilometers.

Navigational charts and dead reckoning are also part of the navigational tools onboard the submarine, with the MOAS sonar being capable of supplementing the submarine's navigation, if used wisely.

While near shore, port facility navigational aids can also be used to calculate the submarine's position.

[Pharthan]

Armament
Write-up by Lamoni

The Dadao's main armament consists of six five hundred thirty-three millimeter torpedo tubes, capable of launching torpedos, anti-shipping missiles, and mines. The primary torpedo carried by the Dadao class is the LA-91 Iaculum heavyweight torpedo, but any five hundred thirty-three millimeter diameter torpedo can be used. The torpedo room can hold any combination of forty torpedos or AShMs, or it can hold up to eighty mines.

The secondary armament consists of thirty-six VLS cells, each capable of holding a single LY4046 Dawnbringer SLBM, as well as firing it via gas charges instead of the more common piston based system. In addition, these same tubes can also be fitted with Common Weapon Launcher Modules at a rate of one CWL per VLS tube, in order to fit different types of weapons or features to the submarine. Removing the CWL module from a VLS tube will again permit the modular VLS tube to fit a Dawnbringer SLBM, and different modules can be fitted at need.

There are multiple different types of Common Weapon Launcher modules, and each type can hold one of the following:

-7x LA-1330 Contrado , AGM-7 ARROW , LRC-2100 Yore, LY589 Hellion , LY589B Hellion II , or similar Cruise Missile (total of up to 252)
-7x AGM-30/NRAM-30 BROADSWORD Surface to Air Missile (total of up to 252)
-1x Halcyon Arms MQ-21 Wasp Submarine launched UCAV (and associated equipment)
-1x REMUS 6000 Autonomous Underwater Vehicle (and associated equipment)
-1x Special Forces Commando Equipment Storage Module

Derived from the twin concepts of STANFLEX modules and Legos, the Common Weapon Launcher Modules make use of the plug and play hardware concept, interfacing with the computers onboard the submarine for efficient operation. Software can easily be replaced or upgraded as needed, and the ship is ready to set sail within a few hours after the modules have been installed. Module training simulation capabilities enable the crew to train on the functions and abilities of any of the modules while underway. Modules can be installed on the submarine in any amount (up to the number of VLS tubes), or in any combination, as desired for the submarine's given mission. Except for the AUV, the weapons for these modules (as well as the SLBMs and torpedoes) must be purchased separately. The REMUS 6000 AUV design blueprints come with the submarine, allowing the purchasing nation to manufacture it right away.

The REMUS 6000 AUV system is a multi-role Autonomous Underwater Vehicle, capable of diving to depths of up to 6,000 meters, and using various sensors to fulfill multiple roles from mine detection to sea-floor mapping, to underwater image taking, and even as an auxiliary satellite communications device. The AUV has a typical endurance of sixteen hours, allowing the parent submarine to collect large amounts of potentially useful data, and even be able to participate in the search for downed aircraft, or submarines in distress. The submarine can either control the AUV via acoustic modem, or it can pre-program the AUV to perform a mission, and then the submarine can return when the AUV's mission is complete.

Launched under its own power for the VLS tube in which it is housed, the AUV is recovered by traveling to a pre-arranged position and depth, where a smaller underwater vehicle will be deployed from the VLS tube from which the AUV was launched, dragging the AUV back into the VLS tube. Once the water has been pumped out of the VLS tube in question, maintenance or other interaction with the AUV can be carried out.

The modules can be removed or replaced by any facility with cranes of the proper capacity, meaning that ships do not need to be taken out of service for a significant amount of time in order to install the desired capabilities. Alternatively, if the submarine itself needs extended repairs, the modules themselves can be used on other Dadao class submarines, if operational conditions require this. As any future Lamonian SSBN/SSGN classes would also use the same CWL module system, the modules can be used on these successors, allowing for a much smaller capability gap, as any new ships using the system do not have to have the modules built-in, therefore lowering overall construction costs, and decreasing construction times for new submarines.

In addition, modules can be stored in controlled conditions when not in use, lowering the amount of preventative maintenance that the modules would otherwise require.

[Pharthan]

Countermeasures
Write-up by Lamoni

The Dadao class is protected from enemy torpedos by the Umbro countermeasures suite. The system starts with the torpedo defense computer, which is tied into the submarine's sonar suite and combat management system. Programmed with advanced defensive algorithms, the Umbro suite can be set to either automatic or semi-automatic (man in the loop) modes.

The Umbro countermeasures suite also contains torpedo defense simulations, which are a valuable training aid, and can be programmed with the latest defense algorithms should new situations or solutions arise. No decoys are launched during these simulations, but the system otherwise acts as normal.

A typical Umbro operational sequence would look like the following:

1.) The protected submarine's sonar detects an incoming enemy torpedo
2.) The protected submarine's CMS is alerted
3.) The protected submarine's CMS alerts the Umbro system
4.) Umbro's defense programming analyzes the threat
5.) Pre-programmed response (automatic or semi-automatic) is selected
6.) The selected pre-programmed response is executed
7.) Torfector decoys are launched
8.) Umbro displays suggested course and depth for evasive maneuver

Torfector Decoy

Decoy shell composition: RHA steel
Diameter: 101 mm
Length: 1,020 mm
Weight: 15 kg
Warhead: 5 kg Composition B2211 High Explosive underwater blast
Power source: Thermal Battery
Propulsion: pump-jet propulsor
Operating Depth: 10-500 m
Operating Time: 5-10 minutes

The Torfector is a rapid response, fourth generation torpedo decoy, designed to work against the latest in both light and heavyweight torpedo threats.

Upon launch, the Torfector decoy will use its small pump-jet propulsor to move a safe distance away from the protected submarine, where it will begin using advanced acoustic signals meant to lure the torpedo towards the decoy. Once the decoy senses that the targeted torpedo is nearing its closest point of approach, the decoy self-destructs, ensuring that the torpedo cannot re-attack the protected submarine. Use of RHA steel for the casing of the Torfector decoy allows the decoy to be used in depths of up to 500 meters, which is deeper than the effective depth for other modern torpedo decoys. Each Torfector decoy is intended to be able to first acoustically seduce, then damage or destroy a single enemy torpedo, but multiple decoys can be launched, if desired.

The Torfector's underwater blast warhead is composed of Composition B2211, which is also notably used in the Lamonian LA-91 Iaculum Heavyweight Torpedo. Composition B2211 is composed of 20% RDX, 40% Ammonium Perchlorate, 16% Aluminum, and 24% Hydroxyl-terminated polybutadiene (HTPB). Composition B2211 is a high-impulse, high-bubble-energy, insensitive explosive that conforms to NATO’s STANAG 4439 and France’s Murat-2 standards. The warhead is intended to damage or destroy the incoming torpedo.

[Pharthan]

Crew Services & Amenities
Write-up by Lamoni and Pharthan

Crew amenities, for the most part, are as standard with any Pharthan submarine. Most individual sailors are allotted their own "Coffin-Rack," with storage underneath the rack, which sits in a tray that can be lifted to expose personal storage space, as well as a personal locker. Each rack space comes with a personal reading light, towel-hangar, emergency egress breathing device stowage, personal six-outlet power strip, and a state-of-the-art Smart Reveille Suite, or SRS. Some of these racks, especially for smaller submarines, must be "hot-racked," meaning that multiple sailors, usually only two, must share a rack. For these cases, the SRS may be keyed to either individual.

The SRS monitors the sleep pattern of the sailor, and can be programmed in with the applicable Watchstation Schedule, Morning Routine & Muster, et cetera. For those requiring certain amounts of sleep such as pilots, it can also advise the sailor on when they should be falling asleep. The SRS is a computer roughly the size of a smart-phone, built into the rack itself and is tamper resistant. It also includes vibration sensors which are, as a standard, built into the walls and base of the rack, as well as separate remote sensors to be able to differentiate natural ship motion from the motions of the sailor.

To promote healthy sleep, the SRS will begin playing soft music of the sailor's choice to ease them awake within the optimal period prior to their next appointment, as well as emitting "peaceful" light. The SRS also monitors temperature, and features a fan to bring in air from outside of the rack, with a heating element should the rack be too cold.

In the event the sailor is late for watch or muster, a louder alarm and brighter lights will be emitted. The speakers for the sounds are directed inward, and additional sound-proofing is provided to prevent disturbing other sailors.

While differing on each ship and in each compartment slightly, each berthing location houses between twelve and 24 enlisted sailors. Officer berthings may be singular, double, or a quartet, depending on rank and station. Each berthing space comes with one computer, which, when available, is linked to the ship's internet and unclassified network; internet browsing on this network is often limited for security reasons, though general social media is allowed. A separate web-browser notebook is also provided to allow sailors to download movies, games, videos, et cetera, and more extensive chat with family. While still monitored for security reasons, this is not connected to the ship's unclassified data network and is more free to use. However, due to the nature of being onboard a submarine, internet connection is not always available, and may be of limited bandwidth when it is available.

Each berthing space has an ample amount of electrical outlets and storage space, both communal and personal, to allow for personal gaming systems, and each berthing space has one large flatscreen TV, with space for an extra. Additionally, every berthing space has their own minifridge and microwave oven.

For every forty sailors there is an additional community space, allowing for more activities to include the watching of movies, TV, gaming, et cetera, without disturbing those sleeping at the time.

For every sixty sailors there is at least one head, to include two showers, two toilet stalls, and three sinks, though some areas may include more based on availability. These are often of stainless steel construction for sanitary reasons, and the shower-stalls are curtained off, though some may include a hard vanity door.

Gym services include rowing machines, various styles of treadmills, yoga mats and equipment, sports equipment for any open areas, and more at the request of the ship's recreational officers. Loose weights are not allowed onboard the submarine, and elastic strength bands must be used instead for strength-training. Each of the various types of equipment is mounted on a shock-absorbing system to prevent creating additional noise detectable from outside of the boat, and equipment is selected specifically for quietness.

Biodegradable trash disposal is handled by means of a smaller tube not unlike that used for torpedos. Dry waste is consolidated using a trash compactor and then placed in special cans. These cans are fabricated on board from prepunched galvanized, perforated steel sheets, using a roller tool. The resulting cans are 72.39 centimeters long and 22.86 centimeters in diameter. They have metal tops and bottom caps. Wet waste is disposed of the in the same way, except that a food grade aluminum foil tri-laminate bag is placed inside of each "wet can." The tri-laminate bag ensures that none of the wet waste leaks from the container, and is sealed when full.

Metal weights are added to the interior of the cans, ensuring that the cans will go to the bottom. The cans are ejected from the submarine using a trash disposal unit (TDU), which is a long cylindrical, vertical tube connected to the ocean through a ball valve. Several cans are placed atop one another in the TDU, the top of the TDU is sealed by closing a pressure cap, the ball valve is opened, and the cans ejected through a combination of gravity and air pressure. It should be noted that this procedure can compromise the submarine's acoustic stealth by generating noise.

Trash which does not biodegrade is stored inside of the submarine until it can be off-loaded in port facilities.

The Dadao class can carry special forces commandos with very spartan accommodations. They can enter and exit the submarine through the six-man after escape trunk, which can also fit a DSRV or ASDS type mini-submarine, if required.

Food is provided for both officers and enlisted from the ship's galley, which uses all electric cooking equipment in order to reduce the noise made from preparing food for the crew. The endurance of the submarine is determined by maintenance and the amount of food stored onboard. The Dadao class can carry enough food for one hundred twenty days of operation before the submarine must resupply.

In order to obtain purified water, the Dadao class uses a distillation plant that heats seawater to water vapor, which removes the salts, and then cools the water vapor into a collecting tank of fresh water. The distillation plant on some submarines can produce 38,000 - 150,000 liters of fresh water per day, and most of this water is used mainly for cooling electronic equipment (such as computers and navigation equipment) and for supporting the crew (for example, drinking, cooking and personal hygiene).

There are two washing machines, and two clothes dryers on board the submarine. This is enough for laundry to be conducted on a weekly basis by each of the submarine's operational divisions (command, weapons, sonar, engineering). As always, the operation of these machines produces noise, and can help to compromise acoustic stealth, so care should be taken when operating them, even though like other heavy electronic devices onboard the submarine, the washer and dryer are rafted.

Computer controlled electrolysis of water is used to create and maintain a breathable atmosphere in the submarine, while atmospheric scrubbers cleanse the air of toxic or otherwise harmful substances. Meanwhile moisture is prevented from condensing inside of the submarine via dehumidification technology. Climate control is maintained using electrically powered heaters and air-conditioners for the benefit of both the crew, as well as any electronic devices onboard the submarine.

[Pharthan]

Countermeasures
Write-up by Lamoni

Should the submarine encounter serious trouble and need rescue, there are multiple systems assigned to help the crew to rescue their submarine, and escape alive.

1.) RESUS - The Resus system is a series of solid-fuel gas generators, which can be used to empty the ballast tanks in an emergency, thus helping the submarine to reach the surface. The solid-fuel propellant for the Resus system consists of 157 kilograms of Glycidyl-Acido-Polymer and Strontium Nitrate, which generates a gas of 34% Nitrogen, 36% Carbon Di-oxide, and 30% water. While this system can be used at any water depth, it is considered to be especially useful in deep water, where the submarine might otherwise reach crush depth.

2.) Emergency Sonar Beacon - A submarine in distress raises the urgent need for quick detection and salvage. Search and rescue highly depend on efficient systems which alert passing vessels and provide locating signals to rescue units. The use of a low frequency sonar transducer provides very long ranges of detection and a high frequency sonar transducer offers very precise guidance of rescue equipment in the close range. The EBS system uses active sonar pings in both high and low frequencies in order to assist rescuers in locating the stricken submarine more quickly. The system can be activated manually, or automatically by remote water contact switches coupled with water pressure sensors.

3.) SEPIRB - The Submarine Emergency Position Indicating Radio Beacon or SEPIRB, is a radio signaling device used for locating a submarine in distress. The SEPIRB is stored onboard the submarine, and at the time of the emergency retrieved from storage and launched. The submarine may be surfaced or submerged at time of launch.

The SEPIRB surfaces and transmits a digital message to the submarine owner's national satellite network, which obtains the position of the SEPIRB to within 100 yards using an GPS receiver onboard the SEPIRB. The transmitted message contains the current elapsed time since activation and the submarine's Unique Identifier code until a valid location is obtained from GPS (the "initial location"). Once the initial location is obtained from GPS the transmitted message contains the current elapsed time, identifier code, initial location obtained by GPS, and elapsed time associated with the initial location. If no GPS location is obtained and/or transmitted by the Submarine EPIRB then its location (to within approximately 3.2 kilometers) will be determined by standard satellite direction-finding methods.

Six hours after actuation, the SEPIRB begins to transmit a 121.5 MHz beacon which is used both in locating/retrieving the buoy and as a backup to the national satellite system message transmissions. The SEPIRB continues both the message transmissions and beacon until either the batteries are exhausted or until the device is retrieved and manually deactivated.

The 100 centimeter long by 7.6 centimeter diameter SEPIRB unit is constructed of Aluminum, and has a weight of 3.6 kilograms. The SEPIRB unit runs on a LiMnO2 battery, which gives it over forty eight hours of battery life.

4.) Submarine Escape Immersion Equipment Mk. X - The SEIE Mk. X suit is a whole-body suit and one-man life raft, designed by British company RFD Beaufort Limited, that allows submariners to escape from a sunken submarine. The suit provides protection against hypothermia and is rapidly replacing the Steinke hood rescue device. The suit allows survivors to escape a disabled submarine at depths down to 183 meters, at a rate of eight or more men per hour, via the disabled submarine's escape trunk. A typical assembly comprises a submarine escape and immersion suit, an inner thermal liner, and a gas-inflated single-seat life raft, all contained in an outer protective stowage compartment.

The intention of the suit is not only to keep the escapee dry and protected from cold shock during ascent, but the suit also acts as a thermal-efficient immersion suit at the surface, with the goal of providing full protection. It provides sufficient lifting force to take the escapee from the submarine to the surface at a "safe" speed of approximately two to three meters per second.