You are on a Mariner class cargo vessel. Your drafts are: FWD 17'-04", AFT 19'-04". You wish to increase the calculated GM of 3.0' to 4.2'. What tanks should you ballast? (Use the white pages in the Stability Data Reference Book.)

Correct Answer: Option A — Tanks: DB3, DB4

Consulting the Mariner class trim and stability tables for the given drafts and initial GM indicates that ballasting double bottom tanks DB3 and DB4 provides the necessary vertical moment and weight addition to achieve the target GM of 4.2 feet.