You are on a Mariner class cargo vessel. Your drafts are: FWD 21'-04", AFT 23'-04". You wish to increase the calculated GM of 4.8' to 5.8'. What tanks should you ballast? (Use the white pages in the Stability Data Reference Book.)

Correct Answer: Option D — Tanks: DB4, DB7

Applying stability reference tables for the given draft conditions determines that ballasting double bottom tank DB4 and deep tank DT7 provides the precise vertical center of gravity reduction needed to elevate the metacentric height from 4.8 to 5.8 feet.