Telfer Method — Semi-Displacement Resistance

Empirical resistance estimation for semi-displacement hulls (0.4 ≤ Fₙ ≤ 1.2).

Froude Number Fₙ: —

Reynolds Number Re: —

Friction Coefficient C_f: —

Residuary Coefficient C_R: —

Total Resistance R_T: — kN

Delivered Power P_D: — kW

The Telfer method combines ITTC friction with an empirical residuary term tuned for semi-displacement hulls.

Report: Telfer Method — Semi-Displacement Resistance

—

Background

Telfer (1967) developed correlations from semi-displacement hull experiments (0.4 ≤ Fₙ ≤ 1.2).

Residuary coefficient: \( C_R = 0.006 + 0.004F_n^2 + 0.002((L/B)-5)/5 - 0.003(C_P-0.65) \)

Total resistance: \( R_T = 0.5ρV^2S(C_f + C_R) \), with friction \(C_f\) per ITTC’57 and estimated wetted area \(S ≈ 1.7LB\).