Halcyon-class SSN (Fast Attack Boat)
Speed: 40 knots (surfaced)(45 on LIHBS), 43knots (submerged)(48 on LIHBS)
Depth: 2,250 feet
Propulsion: (2) S10W Liquid Metal Cooled Thermal-Fission Reactor
8 VLS Pods (4 ESSMs/3 Tomahawk missiles/3 Harpoon missiles, 12 Stinger missiles/ 1 UCAV)
8 Torpedo Tubes (Bow)
4 Torpedo Tubes (Aft)
84 Anti-Torpedo active countermeasures/explosives (42 PORT/STBD)
16 (8 PORT/STBD) Passive Countermeasures
2 ASDS (Internal Bay)
1 ASDS (External Mount)
The S10W LCTR Reactor Plant is vastly upgraded from the S9W LCTR on the Halcyon-class Block II submarine. Virtually no support systems are used, and the reactor is cooled by conduction/convection heat transfer of seawater to the outside of the reactor vessel for emergency situations, but primarily by a vast number of high-efficiency thermocouples, rendering the entire steam-production aspect of all other reactor plants obsolete. Once heated to operating temperature, thermal driving head is maintained in order to keep the reactor plant itself entirely quiet; absolutely no sound is produced.
With the elimination of the Machinery Room and Engine Room of other submarines, a second S10W reactor plant was able to be installed, as well as expanded berthing compartments, supply, and the ability to house more special forces units, including an additional ASDS.
Personnel numbers would have been lowered from the Block II class due to the enhanced technology, save for the added reactor plant needing additional nukes to operate it.
The propulsor set is made up of a series of internalized step-DC-powered pumps, both positive displacement and centrifugal, eliminating noise produced by traditional props, as well as allowing the submarine to go faster without cavitating.
The Block III is kept quiet by a battery of acoustic dampeners, absorbing noise to prevent it bouncing off of the hull, and augmented by yet another series of ambient-noise generators, which analyze the surrounding ambient noise and generator their own similar noises well enough to fool even computer sonar-listeners - thus ridding the worry of sub commanders about becoming "a hole of silence in the ocean."
Despite being able to have a SONAR view behind itself, as the lack of propeller and engine room now allow for such, it still maintains a pair of towed-sonar array/decoys for redundancy.
From the back half of the conning tower down to the bottom of the hull is a very large escape pod, which is able to be sealed and ejected from the rest of the hull to allow for a last-ditch escape should the submarine be compromised. It houses much of the berthing and food-storage spaces.
By far the craziest addition to the submarine is the Liquid Hydrogen Booster System (LIHBS), which takes water from the two reactor's shield tank that has radiolidically decomposed and separates it out via centrifuge, sending oxygen into the machinery and conn spaces, and trapping hydrogen with a cooling tank, where it is cooled until a liquid, and further subcooled. During tactical situations, this liquid hydrogen is run through channels in and around the reactor, acting as a high-efficiency moderator, vastly increasing it's capable output power, allowing for an "overdrive."