Dock Water Allowance Calculator

Formula

The formula to calculate the dock water allowance is:

\[ DWA = \frac{D_d - D_s}{ρ_s - ρ_d} \]

Where:

\( DWA \) is the dock water allowance
\( D_d \) is the displacement in dock water
\( D_s \) is the displacement in sea water
\( ρ_s \) is the density of sea water
\( ρ_d \) is the density of dock water

What is Dock Water Allowance?

Dock water allowance (DWA) is a term used in marine engineering to describe the difference in displacement between a vessel floating in dock water and the same vessel floating in sea water. Dock water typically has a lower density than sea water, which means a vessel will displace more water and sit lower in the water when in dock water compared to sea water. The dock water allowance is an important factor to consider for accurate loading and stability calculations, ensuring that the vessel operates safely and efficiently in different water conditions.

Example Calculation

Let's assume the following values:

Displacement in Dock Water (D_d) = 5000 tons
Displacement in Sea Water (D_s) = 4800 tons
Density of Sea Water (ρ_s) = 1.025 tons/m³
Density of Dock Water (ρ_d) = 1.000 tons/m³

Using the formula to calculate the dock water allowance:

\[ DWA = \frac{5000 - 4800}{1.025 - 1.000} = \frac{200}{0.025} = 8000 \]

The dock water allowance is 8000 tons.