Froude Estimator — Resistance Prediction

Quick empirical estimation of total resistance using ITTC friction & Froude-based residuary correlation.

Froude Number Fₙ: —

Reynolds Number Re: —

Friction Coefficient C_f: —

Residuary Coefficient C_R: —

Total Resistance R_T: — kN

Delivered Power P_D: — kW

Enter length, beam, speed, and (optionally) surface area. If not given, S = 1.7×L×B is used.

Report: Froude Estimator — Resistance Prediction

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Formula Notes

Residuary term correlation: \( C_R = 0.004 + 0.0025 F_n^{2.5} \)

Friction (ITTC ’57): \( C_f = 0.075 / (\log_{10} Re - 2)^2 \)

Total resistance: \( R_T = 0.5ρV^2S(C_f + C_R) \), power \( P_D = R_TV / η_D \).