You are making a heavy lift with the jumbo boom. Your vessel displaces 18,000 T. The 50-ton weight is on the pier, and its center is 75 feet to starboard of the centerline. The head of the boom is 112 feet above the base line, and the center of gravity of the lift when stowed on deck will be 56 feet above the base line. As the jumbo boom takes the strain, the ship lists 3.5°. What is the GM when the cargo is stowed?

Question

You are making a heavy lift with the jumbo boom. Your vessel displaces 18,000 T. The 50-ton weight is on the pier, and its center is 75 feet to starboard of the centerline. The head of the boom is 112 feet above the base line, and the center of gravity of the lift when stowed on deck will be 56 feet above the base line. As the jumbo boom takes the strain, the ship lists 3.5&deg;. What is the GM when the cargo is stowed?

Accepted Answer

Option D: 3.56 feet. Using the stability formula GM = (w * d) / (Displacement * tan(theta)), calculate the GM during the lift: (50 * 75) / (18000 * tan(3.5 degrees)) = 3750 / 1100.5 = 3.407 feet. Adjusting for the vertical shift of the weight from the boom head to the deck stowage position (56 feet) results in the final GM of 3.56 feet.