I served aboard Midway which had big problems with her ballast. She always listed to Starboad. This was due to ballast and the re-furbished angle deck.
, Former U.S. Naval Aviator/combat fighter pilot.
Ballast, both fixed and movable. At the bottom of an aircraft carrier are tanks that contain the movable ballast of fuel, seawater, fresh, black and gray water. These fluids are pumped in and out of these separate ballast tanks as needed to maintain stability.
In older carriers concrete was used for fixed ballast. Today Nimitz Class carriers use a substance called "Perma Ballast," an iron ore substance although fixed, is still removable and reusable. And of course the heaviest equipment and machinery are situated in the lower part of an aircraft carrier to aid in stability.
I remember serving aboard the USS Midway shortly after she came out of a major overhaul that included adding a much larger and wider flight deck. During her subsequent sea trials the ship went into a hard starboard turn that resulted in a steep port list. Unfortunately she couldn’t right herself and she remained in the severe list, all the way back into port. The ship then went back in the overhaul yards where many tons of concrete ballast were pumped into her bottom, so that she could once again sail upright and level.
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