Prismatic coefficient

[simon whitehouse]

Hello,

Can anyone clarify how delftship calculates the Cp of a model?

Using the hydrostatics feature on delftship, It indicates my hull to have a prismatic coefficient of 0.42- but if I go about it the old fashioned way, and divide the displaced volume by the sum of (max. cross sectional area multiplied by the waterline length) it gives 0.49.

Just trying to understand why there is a difference- It’s highly possible that I’ve simply got the wrong end of the stick…

Simon.

[Marven]

Delftship doesn’t use the max. cross section area. Instead it uses the cross section are of the midship section. For merchant ships this generally also is the max. cross section area. For yachts and boats this is not necessarily the case. Go to the project settings and modify the mid ship location so it matches the loacation of the max. cross section area.

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