🔍 Key Concepts

• Use Archimedes’ principle: the weight of water displaced equals the vessel’s total weight at that draft. • Compute the underwater volume using the barge’s length, width, and draft shown in the illustration (assume box-shaped underwater body). • Convert displaced volume of salt water to long tons using the proper weight of 1 cubic foot of salt water.

💭 Think About

• What is the underwater volume of the barge at an 8‑foot draft, based on the dimensions in the figure? • Given the weight of 1 cubic foot of salt water, how many long tons does that underwater volume represent? • Once you know the total displacement at 8 feet, how do you use the barge’s light weight (empty weight) to find just the cargo weight?

✅ Before You Answer

• Be sure you are using the correct density for salt water (in pounds per cubic foot), not fresh water. • Convert from pounds to long tons (2240 lb per long ton) before comparing with the choices. • After finding total displacement, subtract the light ship weight (22.9 LT) to isolate the cargo weight only.