Block Coefficient (Cb)
Compute a ship's block coefficient (Cb), Cb = ∇/(L·B·T), the ratio of the displaced (carene) volume to the enclosing box (length × beam × draft). It measures how 'full' the hull is: slow cargo ships have a high Cb (~0.8); fast, fine vessels a low Cb (~0.5). It is one of the central parameters of naval architecture. Enter the displaced volume, the length, the beam and the draft.
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Coeficiente de bloco (Cb)
O coeficiente de bloco responde: o quanto do paralelepípedo que envolve a parte submersa do casco está realmente preenchido por ele? Cb = ∇/(L·B·T), o volume de carena dividido por comprimento × boca × calado. Um casco em forma de caixa teria Cb = 1; cascos reais ficam entre ~0,4 e ~0,85. Navios cheios e lentos (petroleiros, graneleiros) têm Cb alto (~0,80) para maximizar a carga; embarcações finas e rápidas (contêineros, navios de guerra) têm Cb baixo (~0,50–0,60) para reduzir a resistência. É um dos primeiros números definidos no projeto de um navio. Informe o volume deslocado, o comprimento, a boca e o calado.
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Prismatic Coefficient (Cp)
Compute a hull's prismatic coefficient (Cp), Cp = ∇/(Am·L), the ratio of the displaced volume to that of a prism with the midship section area (Am) along the whole length. It indicates how volume is distributed lengthwise: a low Cp concentrates volume amidships (good for low speeds), a high Cp pushes it to the ends (better at high speeds). It is decisive in resistance design. Enter the displaced volume, the midship section area and the length.
Power by Admiralty Coefficient
Estimate a ship's propulsive power by the Admiralty formula, P = (∆^(2/3)·V³)/C, from the displacement (∆, t), the speed (V, knots) and the Admiralty coefficient (C), characteristic of similar hulls. It is a classic, fast method to predict the required power in the preliminary design stage, based on similarity with existing ships. The V³ dependence shows the high cost of speed. Enter the displacement, the speed and the coefficient C.
Reserve Buoyancy
Compute a vessel's reserve buoyancy, R = (total_volume − submerged_volume)/submerged_volume·100%, the percentage of watertight volume above the waterline relative to the submerged volume. It is the safety margin against sinking: the larger it is, the more cargo or flooding the hull tolerates before submerging. It defines the freeboard and the damage survivability. Enter the total watertight volume and the submerged volume.
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