Prismatic coefficient (CP)

The prismatic coefficient $C_P = \nabla / (A_M \cdot L)$ relates displaced volume to a prism of the midship section area $A_M$ run over the length, so $C_P = C_B / C_M$. It describes longitudinal distribution of buoyancy rather than overall fullness. Low $C_P$ (about 0.55 to 0.60) concentrates volume amidships and suits high Froude-number forms; high $C_P$ (0.75 and up) spreads volume toward the ends. Series-60 and Taylor-Gertler powering data are organized by $C_P$.