🔍 Key Concepts

• Trim and draft change: How adding weight forward affects forward and aft drafts and the vessel’s drag (difference between aft and forward drafts). • LCG (Longitudinal Center of Gravity) and LCF (Longitudinal Center of Flotation): How distance between them creates a trimming moment when weight is added. • Use of moment-to-change-trim tables and TPC (tons per centimeter immersion) or similar data in the Stability Data Reference Book blue pages.

💭 Think About

• First, compute the vessel’s initial drag from the given drafts. Then determine what the drag must be when the trim by the stern is 18 inches and what change in trim this represents. • Think about how adding ballast to the forepeak (forward of amidships) will shift the center of gravity and change trim—will this reduce or increase stern trim, and by how much? • From the blue pages, identify the moment required to change trim by 1 inch or 1 centimeter at the given draft, then work out the total trimming moment needed and convert that into a weight in the forepeak using its LCG distance.

✅ Before You Answer

• Confirm you correctly convert feet and inches to decimal feet and, if needed, inches to centimeters before using the tables. • Verify you are using the correct waterline/draft condition from the Stability Data Reference Book when reading the trimming moment per unit trim (MCT 1" or MCT 1 cm). • Double-check that the distance for the forepeak LCG (200 ft) is measured from the same reference as the trim moment (usually the LCF or amidships, depending on how your data is presented).