The DEEP DRILLER, at a draft of 60 feet, has 35,000 ft-tons of longitudinal moments. How much ballast should be transferred between tanks 1P and 10P to level the unit longitudinally?
• Understanding what a longitudinal moment represents in terms of trimming a vessel or unit • How shifting a certain weight through a known fore‑and‑aft distance creates a trimming moment • Using the relationship: trimming moment = weight shifted × distance shifted and comparing it to the existing longitudinal moment
• If 35,000 ft‑tons is the trimming moment that must be corrected, what combination of weight and shift distance between tanks 1P and 10P would generate an equal and opposite moment? • Look at the plan or typical tank layout: what is the approximate distance between 1P and 10P in feet, and how does that affect the size of the weight needed? • For each answer choice, if you multiply that weight by the distance between the tanks, does it come close to 35,000 ft‑tons or is it clearly too small or too large?
• Confirm the distance between tanks 1P and 10P in feet from the stability booklet or exam data sheet • Use consistent units: long tons for weight and feet for distance, so the moment is in ft‑tons • Check that the resulting trimming moment from the chosen weight is of the same order of magnitude as 35,000 ft‑tons (not 10 times too big or too small)
No comments yet
Be the first to share your thoughts!