'Plane of flotation' definitions:

Definition of 'Plane of flotation'

From: GCIDE

Flotation \Flo*ta"tion\, n. [Cf. F. flottation a floating, flottaison water line, fr. flotter to float. See Flotilla.]
1. The act, process, or state of floating. [1913 Webster]
2. The science of floating bodies. [1913 Webster]
3. (Com. & Finance) Act of financing, or floating, a commercial venture or an issue of bonds, stock, or the like. [Webster 1913 Suppl.]
Center of flotation. (Shipbuilding) (a) The center of any given plane of flotation. (b) More commonly, the middle of the length of the load water line. --Rankine.
Plane of flotation, or Line of flotation, the plane or line in which the horizontal surface of a fluid cuts a body floating in it. See Bearing, n., 9 (c) .
Surface of flotation (Shipbuilding), the imaginary surface which all the planes of flotation touch when a vessel rolls or pitches; the envelope of all such planes. [1913 Webster]