Prismatic Coefficient
Abbreviation: Cp
Ratio of underwater volume to volume of a prism with cross-section equal to the maximum hull section, length = LBP.
In practice
Naval-architect parameter visible to the seafarer only via vessel particulars. Ships with a high Cp (~0.7) like tankers and bulkers handle differently in heavy weather than fine-form Cp ~0.55 container ships.
Regulatory detail & full definition
The prismatic coefficient (Cp) is the ratio of a ship's underwater volume to the volume of a prism whose cross-section equals the maximum immersed hull section and whose length is the length between perpendiculars: Cp = V / (Am · L), where Am is the maximum section area. It describes how the displacement is distributed along the length: a high Cp (about 0.65-0.75 on bulk carriers) means a fuller-ended hull with greater carrying capacity, while finer, faster hulls such as container ships and warships have a lower Cp (about 0.55-0.65) for a finer entry and run.
Related
Source: Standard naval architecture (Lewis, Principles of Naval Architecture)
High confidence
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