Is there a formula for determing wetted surface area? - SailNet Community
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Is there a formula for determining wetted surface area?

Is there a formula for determining wetted surface area?
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Old 03-10-2012
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Re: Is there a formula for determing wetted surface area?

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Old 03-11-2012
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Re: Is there a formula for determing wetted surface area?

From my copy of Principles of YACHT DESIGN 3rd edition by Lars Larsson & Rolf E. Eliasson:

Quote:
A very fast, but somewhat more approximate method to find the wetted surface is to make use of an empirical formula based on the length, beam, draft, displacement and prismatic coefficient of the canoe body (as shown in Fig 4r.2). For smooth hulls this formula is surprisingly accurate, but if a drawing of the hull is available the method above is recommended...

Sw = Sqrroot (deltac * Lwl) * cuberoot (0.65 / Cm )
Cm = deltac / (Lwl * Bwl * Tc * Cp )

Sw = Wetted Surface
Sqrroot = Square Root
Deltac = Volume displacement
Lwl = Length along the waterline
Cm = Midship section coefficient
Bwl = Beam along the waterline
Tc = ?
Cp = Prismatic coefficient

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Old 03-11-2012
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Re: Is there a formula for determing wetted surface area?

Simplified 'approximations':

For a 'fat assed' boat: (1/2 X length of Waterline X 1/2 of beam squared X 3.14) + (2 X average length X depth of keel) = 1/2 surface area of approx. cone + keel surface area

For a canoe body: (.4 X length of waterline X 1/2 of beam squared X 3.14) + ( 2 X average length X depth of keel)
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