Waterplane area coefficient (CWP)

The waterplane area coefficient $C_{WP} = A_W / (L \cdot B)$ is the ratio of the design waterplane area to its enclosing rectangle, typically 0.65 to 0.90. It governs the second moment of waterplane area $I_T$ and therefore the transverse metacentric radius $BM = I_T / \nabla$, so a fuller waterplane raises initial stability. $C_{WP}$ also sets the tonnes-per-centimeter immersion (TPC) and the position of the center of flotation.