Introduction
Throughout its life a
ship changes its weight, draught, trim and freeboard. The density of water in
which the ship floats varies. Its stability also changes. If its condition at
any stated set of circumstances to be estimated, its condition in a precise
state must be known so that the effect of changes from that state can be
calculated. This precise condition is known as the design condition. For this,
changes from the design and properties of underwater form are calculated for a
complete range of waterlines. This information is known as hydrostatic data and
it plotted against draughts. Draughts are spaced 1 m apart. These curves are
drawn on displacement sheet.
The following
properties are plotted against draught to form hydrostatic curves.
- Volume of displacement
- Displacement
- Longitudinal centre of buoyancy from midship
- Vertical centre of buoyancy above base line
- Water plane area
- Longitudinal centre of floatation from midship
- Tonnes per centimeter immersion
- Longitudinal moment of inertia about midship
- Transverse moment of inertia about central line
- Longitudinal moment of inertia about axis passing through LCF
- Transverse meta-centric radius
- Longitudinal meta-centric radius
- Transverse meta-centre above base line
- Longitudinal meta-centre above base line
- Moment to change trim by 1 cm
- Block coefficient
- Midship section area coefficient
- Water plane area coefficient
- Longitudinal prismatic coefficient
- Vertical prismatic coefficient
- Wetted surface area of hull
nicely written. explanation of each item would help more.
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