You have 6 containers of rig supplies each measuring 8'L by 4'B by 3'H and weighing 1.6 tons each. Each container is stowed on deck. What is the maximum VCG permitted of the remaining cargo if you are carrying rig water and load to maximum capacity? See illustration D037DG below.
• Use the stability letter restriction #3 about the maximum height of the center of gravity of all deck cargo above the main deck. • Use restriction #4 for maximum deck cargo weight when carrying rig water. • Apply the combined VCG formula: total VCG = (sum of weight × height moments) ÷ (total weight).
• How much of the 35 long tons of allowable deck cargo is already taken up by the 6 containers, and how much weight is left for the remaining cargo? • What is the vertical center of gravity (VCG) of each of the 6 containers, measured above the deck, based on its height? • If the total deck-cargo VCG must not exceed 2.0 ft above the deck, how can you use the total-moment equation to solve for the unknown VCG of the remaining cargo?
• Be sure to convert all weights to the same units (long tons) before calculating moments. • Confirm that you are using the total deck cargo limit of 35 LT (because rig water is carried) and not the 50 LT case. • After solving for the unknown VCG of the remaining cargo, compare your result to the choices and check that the combined VCG is ≤ 2.0 ft.
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