SNMB-A (Submarino Nuclear de Misseis Balísticos-Alfa) Project
Following the end of the Second Great Northern War, it had once again become clear that the submarine force was an integral part of the Commonwealth's naval force, being instrumental in the isolation of German and Intermarium colonial holdings in Africa along with securing the Pan Oceanic Pact's eastern flank against the capable Japanese and Chinese navies.
However, in the following years, the development of strategic nuclear weapons had begun to spiral out of control across much of the major powers, and although Portugal had vast knowledge and experience in the development/operation of nuclear reactors, the weaponization of the tecnology had so far not been deemed of importance, mostly because of unreliable delivery systems worldwide, and low stockpiles up to then. Now, has the arms race once again spiraled out of control, it was feared that Portugals european mainlandm along with its east asian domains became an easy target to nuclear strike in the face of an unempressive WMD deterrent.
As such, it was decided to develop a cost effective, "small" yet extremelly capable nuclear deterrent, and given the nations experience in submarine shipbuilding, and the inherent survivability of the platform, a ballistic missile sub was to be procured, sharing component with Portugal's and Australia's next gen SSNs, namely the reactor, drive train and sensor suite.
SNMB, as envisioned, would be an hybrid single/double hull design.
The single hulled forward compartment (4 decks) would be reserved for crew accomodations, torpedo room, control room, etc... along with the 16 missile silos.
The doble hulled rear compartment (3 decks) would be reserved for the machinery spaces, reactor and respective control rooms.
The submarine was to use a natural circulation, pressurized water nuclear reactor and an electric drive which removed the need for reduction gears, bringing down noise levels tremendously. Rafting of the machinery and the use of anechoic coating were also required.
Sensor suite and combat managment system was to be completely shared with the next gen SSN. It includes 6 dual mode main flank arrays, each complemented by a passive ranging sonar. In the bow there would be a conformal horseshoe shaped dual mode array, complemented by a low frequency mine detection sonar in the sail and by a towed array in the back. Also included on both sides was a pair of towed accoustic decoys for extra survivability in case of detection.
The sub's unique double hull design allowed for some extra safety measures. Two escape capsules were located behind the missile compartment and above the reactor. Combined these could theoretically fit the entire 91 person crew, and could be launched on the move across the entire operating depth range of the sub. These were supplemented by and emmergency distress floater.
At last, in accordance with the submarine's deterrent role, a comm floater was also present in an hangar located in the middle of the 2 escape capsules. This would allow fast and reliable communication with strategic decision centers in case of need.