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Question 2269Deck Safety70% to pass

A bulk freighter 680 ft. in length, 60 ft. beam, with a waterplane coefficient of .84, is floating in salt water at a draft of 21'. How many long tons would it take to increase the mean draft by 1"?

AI Explanation
The correct answer is B) 81.6 tons. To calculate the increase in draft, we can use the formula: Increase in draft = Change in displacement / (Waterplane area x Density of water). Given the vessel's length (680 ft), beam (60 ft), and waterplane coefficient (0.84), we can calculate the waterplane area as 0.84 x 680 x 60 = 34,560 sq ft. The density of saltwater is approximately 64 lb/cu ft. An increase in draft of 1 inch (1/12 ft) would result in an increase in displacement of 34,560 x 1/12 = 2,880 cu ft. Converting this to long tons (1 long ton = 2,240 lb), we get 2,880 x 64 / 2,240 = 81.6 long tons. Therefore, the correct answer is B) 81.6 tons.

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