MARINE
Boat Speed Calculator
Hull speed · Displacement · Planing · Propeller slip · Speed-length ratio
displacement
planing
Vessel & propulsion parameters
ft
Length at waterline
lbs
Total weight of vessel
HP
in
RPM
%
Typical: 10-20% for planing hulls
Marine speed formulas
- V_hull = 1.34 × √LWL hull speed (kt)
- V_prop = (RPM × Pitch) / (1215 × (1 - Slip/100)) prop speed (kt)
- SL ratio = V / √LWL speed-length ratio
Predicted speed
32.5
kt
Hull speed
7.3
kt
Speed-length ratio
5.93
ratio
Speed envelope
Predicted
Hull speed
Regime: PLANING
Performance factors
Propeller speed
36.9
kt
Propeller slip
15
%
Hull type
Planing
Power-to-weight
16.7
HP/ton
Speed characteristics
displacement/planing
Hull speed
7.3 kt
Propeller speed
36.9 kt
Effective speed
32.5 kt