Question 2271 Deck Safety

The correct answer is B) 69.6 long tons. To calculate the increase in mean draft, we can use the formula for the change in draft due to added weight: Change in draft (in inches) = Added weight (in long tons) / (Waterplane area (in sq. ft.) x Waterplane coefficient x Salt water density (64 lb/cu ft)) Given: - Length: 580 ft - Beam: 60 ft - Waterplane coefficient: 0.84 - Draft: 21 ft Waterplane area = Length x Beam = 580 ft x 60 ft = 34,800 sq. ft. Plugging in the values, we get: Change in draft (in inches) = Added weight (in long tons) / (34,800 sq. ft. x 0.84 x 64 lb/cu ft) 1 inch = Added weight (in long tons) / (2,231.04 long tons) Added weight = 1 inch x 2,231.04 long tons = 69.6 long tons Therefore, the correct answer is B) 69.6 long tons. The other options are incorrect because they do not correctly apply the formula and calculation to determine the added weight required to increase the mean draft by 1 inch.