🔍 Key Concepts

• virtual rise in G when a ship takes the ground (ground reaction acting at or near the keel) • treating the weight aground as if a weight were shifted vertically from the keel (K) up to the original center of gravity (G) • using the ratio of weight aground to total displacement to find how far G appears to move

💭 Think About

• How does putting part of the ship’s weight on the ground change the portion of weight still supported by buoyancy, and where does that new upward force act? • If the ship’s G is 21.5 ft above the keel, what is the maximum possible upward shift of G if all the weight were transferred to the keel—and then what fraction of that corresponds to only 2500 tons out of 12,000 tons? • Should the virtual rise in G be larger or smaller than the original KG of 21.5 ft? Use this to eliminate unreasonable answer choices.

✅ Before You Answer

• Be sure you are using the ratio of weight aground to the ship’s total displacement (not the remaining buoyant weight) in your calculation, unless your specific formula says otherwise. • Confirm that the lever arm you are using is from the keel (0 ft) up to the original G at 21.5 ft. • After computing, check that the virtual rise is less than 21.5 ft and that the numerical result is close to one of the options without extra rounding errors.