Question

You are asked to relocate a sunken boat to be used as an artificial reef. The boat's mass is 4,000Kg and the volume of its solid parts is 3m3. Assume the ocean water density is 1.02g/ml. Approximately, what is the minimal volume of an air bag (in liters) that should be attached to it so it can be lifted under water to be moved to its new location (the air bag weighs 10Kg)?

Answer 1

To lift the boat of 4,000Kg under water, the minimal volume of an air bag required is approximately 38,235.29 liters. This is calculated by using the Archimedes' principle, which states that an object submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. Thus, the force required to lift the boat is equal to 4,000Kg, while the weight of the air bag is 10Kg. Therefore, the buoyant force required to lift the boat is equal to 3,990Kg. The volume of fluid displaced is equal to the volume of the solid part of the boat plus the volume of the air bag. Thus, the volume of the air bag required is equal to 3,990Kg/1.02g/ml, which is approximately 38,235.29 liters.