Design Report Guided Missile Submarine SSG(X) - AOE - Virginia ...

SSG(X) Design – VT Team 3 Page 57
CCC space is located on the upper and second decks ahead of the VLS system. Section 0 presents further detail of
the internal combat systems arrangements.
4.2.2 Propulsion and Machinery Arrangements
The preliminary arrangement for the propulsion and machinery equipment was primarily driven by the volume
requirements determined by the optimization. As with all modern submarines the habitability and torpedo spaces
are located in the bow or forward somewhere. The stern and aft portions of the boat consequently are designated for
the main machinery room (MMR) and the auxiliary machinery room (AMR). For stability purposes the variable
ballast tanks must be kept in the bilge. The compensating fuel tank was located between the pressure and envelope
hull around the MMR for quicker distribution to the CAT 3512 diesel engines. The clean fuel tank was also placed
next the MMR only in the bilge inside the pressure hull. Also to increase stability the heavy Zebra batteries are
distributed in the bilge and symmetrically along the center line. The heavy hydrogen hydride was determined to not
be any higher than half the diameter of the submarine. Due to the limited pressure hull space and safety purposes
the hydrogen hydride is located outboard.
4.2.3 Equilibrium Polygon
An equilibrium Polygon provides the boundary for the operational envelope for trim and ballast for SSG(X).
The loads at different loading conditions are calculated and the plotted with the polygon. If the loading conditions
are all within the polygon, they are feasible. If the loading conditions are outside of the polygon, the locations of the
weights must be changed to get all loading conditions inside of the polygon.
The first step in creating an equilibrium polygon with loading conditions is to arrange the tanks and displacing
volumes in the arrangements drawings. The next step is to use the drawings to calculate the longitudinal center of
buoyancy (LCB). In order for the submarine to balance, the longitudinal center of gravity (LCG) must be as close to
the LCB as possible. The next step in the process is to use the drawings to determine the LCG of the entire
submarine. Then, use the drawings to determine the LCGs and volumes for each of the variable ballast tanks.
Starting at the forward-most trim tank and moving aft, fill each tank. Each time a tank is filled, it creates an edge of
the polygon. Once all of the tanks are filled, the tanks are emptied. Starting at the forward-most trim tank, each
tank is the emptied. This creates the other half of the polygon. The last step in the process is to determine the
weights and moments for each condition. The feasibility of the conditions is determined by plotting the loading
conditions onto the equilibrium polygon.
4.3 Initial Balance and Trim
4.3.1 Displacing Volumes
All volumes external to the pressure hull were considered to be a displacing volume. Figure 43 shows all
displacing volumes for SSG(X).
Figure 43 - Displacing Volumes