Admiralty coefficient

The admiralty coefficient C is a dimensionless powering constant defined by C = (D^(2/3) V^3) / P, where D is displacement in tonnes, V is speed in knots, and P is shaft power in kW. It captures the cube-law relationship between speed and power for a hull form and is used to scale power between a known ship and a similar new design, or between operating speeds for the same ship. Typical values run from about 350 for slow full-form bulk carriers to over 600 for fine fast hulls. It assumes geometric and Froude-number similarity and breaks down across large speed changes.