Question 2476 Deck Safety

70% to pass

Your 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?

A 6.04 feet
B 6.23 feet
C 6.51 feet
D 6.76 feet
AI Explanation

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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