A bulk freighter 580 ft. in length, 60 ft. beam, with a waterplane coefficient of .84 is floating in salt water at a draft of 21 ft. How many long tons would it take to increase the mean draft 1"?

Correct Answer: Option B — 69.6

Applying the salt water TPI formula (L * B * Cw / 42) for a 580-foot vessel with a 60-foot beam and 0.84 waterplane coefficient yields: (580 * 60 * 0.84) / 42 = 69.6 long tons per inch immersion.