Question 2476 Deck Safety
70% to passYour vessel displaces 747 tons and measures 136'L by 34'B. You ship a large wave on the after deck. What is the reduction to GM due to free surface before the water drains overboard, if the after deck measures 56'L x 34'B and the weight of the water is 58.6 tons?
The correct answer is C) 6.51 feet. To calculate the reduction in GM (metacentric height) due to free surface, we can use the formula: Reduction in GM = (I/V) * W, where I is the moment of inertia of the free surface, V is the displacement volume, and W is the weight of the free surface. Given: - Vessel displacement = 747 tons - Vessel dimensions = 136'L x 34'B - Water on the after deck = 56'L x 34'B, weight = 58.6 tons Calculating the moment of inertia (I) of the free surface: I = (56 * 34^3) / 12 = 54,912 ft^4 Calculating the displacement volume (V): V = 747 tons / 64 (density of seawater) = 11,672.5 ft^3 Plugging these values into the formula: Reduction in GM = (54,912 / 11,672.5) * 58.6 = 6.51 feet Therefore, the correct answer is C) 6.51 feet.
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