Form Factor (Prohaska)

Three-dimensional extrapolation form factor (1+k) derived from low-Fn resistance data - the ITTC-78 correction that separates frictional from residual resistance.

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

1 + k = 0.93 + 0.4871 \cdot (B/L)^{1.07} \cdot (T/L)^{0.46} \cdot (1 + C_B)^{0.36}

Symbol	Meaning	Unit
$C_B$	Block coefficient
$B/L$	Beam-to-length ratio
$T/L$	Draft-to-length ratio
$1 + k$	Form factor

Source: Prohaska (1966) - Form factor for ship extrapolation; ITTC 7.5-02-02-01 Resistance Test

In short

Three-dimensional extrapolation form factor (1+k) derived from low-Fn resistance data - the ITTC-78 correction that separates frictional from residual resistance.

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