Topic - 11 Damage stability (Stability in the damaged condition)

Damage stability calculations are much more complicated than intact stability. Software utilizing numerical methods is typically employed because the areas and volumes can quickly become tedious and long to compute using other methods.

The loss of stability from flooding may be due in part to the free surface effect. Water accumulating in the hull usually drains to the bilges, lowering the centre of gravity and actually decreasing (It should read as increasing, since water will add as a bottom weight thereby increasing GM) the Meta centric height. This assumes the ship remains stationary and upright. However, once the ship is inclined to any degree (a wave strikes it for example), the fluid in the bilge moves to the low side. This results in a list.

Ø  Floodable Length: The floodable length at any point within the length of the ship is the maximum portion of the length, having its center at the point which can be symmetrically flooded at the prescribed permeability, without immersing the margin line.

Floodable length (in short) is the length of (part of) the ship that could be flooded without loss of the ship.

Ø  Determination of Floodable length is essential to determine

1. How many watertight compartments (bulkheads) are needed
2. Factor of subdivision (How many water compartments flooded without loss of ship)