Displacement Speed

Again, we will use data from our example vessel.

Formula for Speed : Length ratio   True S/L ratio = Knots / square root ( LWL ) (B)     Calculated S/L ratio = 10.665 / cube root ( max DISP / SHP ) (A)     45 motor HP 1 # motors   7.79 Max "hull speed" (knots) 6.00 % transmission losses   7 Reqd speed 42 SHP at prop                     1.35 Speed Length Ratio (B) 1.72 Speed Length Ratio (A)         1.54 Average of (A) & (B)       30  Alternative estimate of SHP reqd based on average of (A) & (B)   20 SHP reqd 42 SHP available 22 SHP for ancilliaries           No Warnings. Sufficient SHP Available Reqd speed within limits for economy