Operium Solutions
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    Fresh water allowance and dock water allowance

    Calculate the fresh water allowance (FWA) and the dock water allowance (DWA) in millimetres from the displacement, the TPC and the dock water density.

    Fresh water allowance (FWA)225.2mm
    Dock water allowance (DWA)135.1mm

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    How we calculate this

    Would you like to know how we calculate this and how it is handled in FOSS? We would be glad to talk it through.

    Frequently asked questions

    What is the difference between FWA and DWA?

    FWA is the allowance for fresh water, DWA the allowance for the water the ship actually lies in. DWA is smaller than FWA as soon as the dock water is saltier than fresh water.

    Where do I find the displacement and the TPC?

    In the ship's hydrostatic tables or trim and stability book, at the summer draft.

    Which unit do I use for the density?

    kg/m³, so for example 1010 for brackish dock water. Valid values are between 1 and 1,025.

    Further reading

    Surveying and cargo controlFresh water allowance and dock water allowance explainedSurveying and cargo controlWhat is a draft survey? Method, formulas and worked exampleSurveying and cargo controlDraft survey report: what goes in it, with a worked example

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