3454. Submarine Trim Dive Weight Growth

Paper

Abstract

This paper examines recent data from SSN 688 Class submarine trim dives that were accomplished prior to and after ma jor overhauls. The trim dives are used to determine unaccounted-for weight change prior to and during the overhaul and to verify that the submarines are properly ballasted coming out of the overhaul. The data show that there is a trend toward negative UWC in both incoming and outgoing trim dives (though this may be due to outliers) and that in both cases the range of UWC is greater than the variable ballast system can absorb. There doesn’t appear to be a pattern of weight growth by shipyard. The magnitude of excess outfit values used has increased in the past few years. The outgoing UWC appears to be influenced more by the experimental error of the trim dive than by the excess outfit value used in the reballasting calculations. However, there is a correlation between the outgoing UWC and the excess outfit values used; using a value of -10 to -20 tons appears to reduce the risk of large UWC from the outgoing trim dive.