Question 4728 Deck General
70% to passA semisubmersible at a draft of 19 feet 9 inches arrives on location planning to deploy eight mooring lines. Each anchor weighs 15 long tons and each mooring line consists of 3,000 feet of 3-inch chain (89.6 lbs/ft). If no ballast corrections are made, what is the expected draft if the average TPI is 60?
The correct answer is B) 18 feet 3 inches. To arrive at this answer, we need to calculate the change in draft due to the weight of the anchors and mooring lines. The total weight of the anchors is 8 x 15 long tons = 120 long tons. The total weight of the mooring lines is 8 x 3,000 feet x 89.6 lbs/ft = 2,148,800 lbs, which is approximately 958 long tons. The total additional weight is 120 + 958 = 1,078 long tons. Using the average TPI of 60, the expected change in draft is 1,078 / 60 = 17.97 feet, or approximately 18 feet 3 inches. The other options are incorrect because they do not accurately reflect the change in draft based on the given information. Option A) 17 feet 9 inches is too low, while options C) 18 feet 9 inches and D) 21 feet 3 inches are too high.
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