The DEEP DRILLER is loaded as shown in the Sample Load Form #2 (Ballasting to Survival). What is the shift in LCG if 100.76 long tons of ballast are added to Ballast Tank #8S to replace the discharge of all bulk materials?
• Longitudinal Center of Gravity (LCG) – how adding/removing weight at a known longitudinal location shifts the vessel’s overall LCG • The basic trimming/LCG shift formula using weight added and its distance from the original LCG • Reading tank data from the Sample Load Form #2 (Ballasting to Survival) – especially the longitudinal location (LCG) of Ballast Tank #8S
• Where is Ballast Tank #8S located relative to the vessel’s original LCG – forward or aft? That tells you the direction of the LCG shift. • How do you combine the original moment, plus the moment of the added ballast, to find the new LCG? Think in terms of total weight and total longitudinal moment. • After finding the new LCG, how do you compare it to the original LCG to determine both the magnitude and direction of the shift?
• Confirm the LCG position of Ballast Tank #8S from the Sample Load Form (don’t assume it’s at midships). • Use consistent units for weight (long tons) and distance (feet), and make sure you divide total moment by total weight to get LCG. • Carefully compute the difference between new LCG and original LCG, and note whether it is forward (−) or aft (+) before matching to a choice.
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