REFERENCES.
(a) NAVSEA S9086-C6-STM-000 - NSTM Chapter 096 (Weights and Stability)
(b) NAVSEAINST C9096.2 - Weight and Stability Requirements for Active Submarines
2.1 PURPOSE. This chapter provides basic information and guidance concerning submarine ballast changes, including mandatory authorization and reporting requirements.
2.1.1 Discussion.
a. The use of ballast is important in maintaining a submarine's stability. Ballast, in most cases lead, is installed in submarines for the following purposes:
(1) To improve transverse stability.
(2) To adjust trim.
(3) To provide adequate immersion.
(4) To eliminate an inherent list.
(5) To permit submarines to submerge with neutral buoyancy and zero trim.
b. An inclining experiment is performed in accordance with the requirements of reference (a). This experiment provides the basic data concerning weight and center of gravity for use in all considerations of stability, reserve buoyancy, immersion, trim, and in determining compliance with the requirements of the weight control program. An inclining experiment is the only satisfactory method of accurately determining the location of the center of gravity of the submarine. Inclining experiments are conducted on each submarine in new construction, after conversion or overhaul and when authorized by Naval Sea Systems Command (NAVSEA) for some Selected Restricted Availabilities (SRA).
c. Initial ship design provides for adequate stability from a light load through full load condition. The design allows a margin for growth, but experience has shown that the margin is quickly used up for several reasons:
(1) The on-going process of modernization over the life of the ship.
(2) The accumulation of an assortment of personal gear and equipment.
(3) Weight removal for compensation being accorded a low priority.
2.2 BALLAST CHANGES. NAVSEA maintains a record of the solid ballast installed in each submarine. These records are valuable in evaluating the ship's stability and seaworthiness, in determining the deadweight and space available for cargo, and in locating valuable material such as lead or iron in the ballast installation when a ship is scheduled for disposal. NAVSEA maintains a system of checks and balances on weight and moment changes when approving alterations. Accomplishment of an alteration involving a weight reduction does not make this saving available to the ship for use when requesting new alterations. NAVSEA expects to utilize this weight savings as compensation for future alterations. New and unexplored sources must be found when recommending weight and moment compensation.
2.2.1 Naval Sea Systems Command Notification. Occasionally, the permanent ballast on a ship may be increased, decreased, relocated, or replaced. Changes in ballast may result from alterations issued by NAVSEA or may become necessary in connection with other repairs or alterations. In order to maintain the accuracy of NAVSEA records, each activity installing or rearranging ballast shall furnish NAVSEA a report, with copies to the Type Commander (TYCOM), Immediate Superior In Command (ISIC) and the Commanding Officer of the ship involved, containing the following data pertaining to the ballast installed, removed or relocated.
a. Material and approximate density.
b. Weight installed at each location.
c. Vertical, longitudinal, and transverse position of center of gravity of ballast at each location.
d. Principal dimensions of each ballast location.
2.2.2 Changes in Ballast. Submarines of the active fleet shall be maintained within stability and buoyancy limits for a state of war readiness. Deviations from this principle are not authorized.
a. Changes in permanent or cargo (temporary) ballast, which includes adding, removing or relocating, shall not be accomplished by Ship's Force, Fleet Maintenance Activities (FMA) or any industrial activity without prior TYCOM approval and NAVSEA written guidance.
b. Additional guidance and procedures concerning the installation or removal of cargo ballast is available in reference (b).
2.3 UNUSUAL CONDITIONS. NAVSEA requires reports to be submitted of any unusual conditions which are considered dangerous or seriously affect the operation of the ship. Report the following situations to NAVSEA, via the ISIC and TYCOM, in accordance with the requirements of reference (a).
a. Excessive rolling.
b. Heeling due to rudder action.
c. Excessive pounding.
d. Inadequate propeller immersion.