Definition
The point within a submerged or floating body through which the total upward buoyant force of the surrounding fluid is considered to act. For a lighter-than-air aircraft, it is the point in the gas envelope through which the lifting force of the displaced air effectively acts.
Plain English
The single point where you can imagine all the lift from the surrounding air or water being concentrated. Picture the entire upward push squeezed into one spot — that spot is the center of buoyancy.
Context Anchor
Seen in seaplane and floatplane discussions, especially when talking about how a hull or float sits in the water and stays stable.
Derivation
From Latin 'boia' through French 'bouée' (a floating marker or buoy). The word 'buoyancy' refers to the upward push a fluid exerts on something inside it. So 'center of buoyancy' simply means the central point of that upward push.
Why Pilots Care
On seaplanes and floatplanes the relative positions of the center of buoyancy and center of gravity determine whether the aircraft remains stable or tends to tip while on the water.
Grounding Statement
When a float rests in the water, the water’s upward support can be treated as acting through one effective point: the Center Of Buoyancy.
Intuition Check
Center does not mean the exact physical middle of the airplane or float. It means the balance point of the water’s upward support, and it can shift as the float or hull sits deeper or changes angle.
Example Sentence 1
The airship's center of gravity hung below its center of buoyancy, giving the craft natural stability in level flight.
Example Sentence 2
During water handling training the instructor emphasized keeping the center of buoyancy aligned to prevent the floatplane from weather-vaning or tipping.