Your vessel's drafts are: FWD 21'-08", AFT 24'-02". The LCG of the forepeak is 200 feet forward of amidships. How many tons of ballast must be pumped into the forepeak in order to have a drag of 18 inches? (Use the reference material in Section 1, the blue pages, of the Stability Data Reference Book)
⢠Use current drag vs desired drag to find the required change in trim (in inches) ⢠From the blue pages, find the shipâs MCT 1" and LCF position at the correct mean draft/displacement ⢠Apply the trim by loading a weight formula using the distance between the forepeak LCG and the LCF
⢠What is the vesselâs present drag (aft draft minus forward draft) and what drag do you want? How many inches of trim must change, and in which direction (by the head or by the stern)? ⢠At the correct mean draft, what are the values of MCT 1" and LCF in the Stability Data Reference Book, and where is the LCF located relative to amidships? ⢠How far (in feet) is the forepeak LCG from the LCF, and how does that distance enter the trim-moment formula to solve for the unknown weight of ballast?
⢠Be sure you use the mean draft that matches the condition after loading, not just one of the end drafts ⢠Confirm you are using the distance between LCG of the added weight and LCF, not the distance from amidships alone ⢠Check that the sign of trim (trimming by the head vs by the stern) matches the effect of adding weight in the forepeak
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