🔍 Key Concepts

• Free surface effect and how it reduces metacentric height (GM) • Second moment of area (moment of inertia) of a rectangular tank surface: I = (breadth^3 × length) / 12 for transverse free surface • Density (or specific gravity) ratio between the liquid in the tank and the surrounding water in the displacement

💭 Think About

• First, work out the free surface moment of inertia for ONE tank using its breadth and length; then account for the fact there are TWO identical tanks. • Think about how to convert the ship’s displacement in long tons into the correct units to match your free surface formula so that the GM correction comes out in feet. • Consider how the specific gravity of palm oil compared to sea water will change the size of the free surface correction—should it be the same as water, larger, or smaller?

✅ Before You Answer

• Be sure you are using breadth (transverse dimension) raised to the third power in the I = (b^3 × l) / 12 formula, not the length. • Check that you have applied the density ratio (SG of liquid / SG of seawater) correctly when calculating the free surface correction. • Confirm that you have multiplied the free surface effect for one tank by two before comparing your final GM reduction (in feet) to the answer choices.