Admiralty Coefficient & Speed-Power Tool Ship Power, Speed & Performance Curve
Estimate propulsion power, speed and comparative ship performance using the traditional Admiralty coefficient, then move beyond the cubic-law shortcut with a fitted multi-point speed-power curve. Simple mode calculates AC, target power and predicted speed at available power. Advanced normalizes operating or trial points for displacement, fits the speed-power exponent, compares cubic and fitted models, applies operational margins, screens MCR/reserve, converts the selected power basis through the propulsion-efficiency chain and builds a full performance curve.
Reference Vessel / Condition
Target Condition
Performance Model & Power Basis
Target Operating Condition
Speed-Power Observation Register
Enter corrected or otherwise comparable points on one consistent power basis. Each included point is normalized to the reference displacement using traditional Δ²⁄³ scaling before fitting ln(P) versus ln(V).
| Use | Speed kn | Power kW | Displacement t |
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