A floating jack-up with displacement of 16,200 kips has its LCG 110.37 feet aft of frame zero (AF0). If 200 short tons are discharged from 120 feet AF0 and 400 short tons are discharged from 150 feet AF0, what is the new LCG?
• Longitudinal center of gravity (LCG) and how it shifts when weight is added or removed • Using a parallel-axis moment calculation: total moment = sum of (weight × distance) about the same reference frame • How removing weight (discharging cargo) affects the vessel’s total displacement and combined LCG location
• First, compute the vessel’s original total moment about frame zero using the given displacement and LCG. What units must the displacement be in to match the cargo weights? • Next, calculate the moments of the discharged weights about frame zero and determine the new total weight and total moment after discharge. • After finding the new total moment and new total weight, how do you compute the new LCG, and which choice is closest to that value?
• Make sure all weights are in the same units (convert kips and short tons consistently). • Confirm that you subtract both the discharged weights and their moments from the original totals, since cargo is being removed. • After calculating the new LCG, check if it makes physical sense: should the LCG move forward or aft relative to the original 110.37 ft, given where the removed weights were located?
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