How do you calculate floodable length?

The floodable length at any point in the length of the ship is the maximum portion of the length, having its centre at the point in question, which can be symmetrically flooded at the prescribed permeability, without immersing the margin line.

What is floodable length curve?

Floodable length curve represents the maximum floodable length of the ship along the ship’s length. This curve is obtained by vertically plotting the floodable length along the ship’s length.

What is permissible length of a ship?

The length between bulkheads on a ship in order to ensure that it will remain afloat if one, or more, compartments are flooded. The permissible length is some fraction of the floodable length. The fraction is called the factor of subdivision.

What is subdivision length?

Subdivision length (Ls) of the ship is the greatest projected moulded length of that part of the ship at or below deck or decks limiting the vertical extent of flooding with the ship at the deepest subdivision draught.

Why margin line is 76mm?

A line drawn at least 76mm below the upper surface of the bulkhead deck at side, (SOLAS). The margin line is a line defining the highest permissible location on the side of the vessel of any damage waterplane in the final condition of sinkage, trim and heel.

What step to be taken to determine whether or not flooding is progressing?

Determination of whether flooding is progressing The first step to be taken is to determine whether or not flooding is progressing. This can be done by a careful survey, including observations to determine the rate of increase of list, trim, and bodily sinkage.

What is subdivision load line?

Subdivision load line is a waterline used in determining the subdivision of the ship. Deepest subdivision load line is the waterline which corresponds to the greatest draught permitted by the subdivision requirements which are applicable.

Is margin a Line?

What we should do before flood?

To prepare for a flood it is important to:

1. Remember, if you decide to build your home in a flood plain, you should elevate and reinforce the home.
2. Keep your furnace, water heater, and electrical panel elevated if you are in an area susceptible to flooding.
3. Construct barriers to keep flood waters from entering your home.

How we can manage the flood?

Some of the common techniques used for flood control are the installation of rock beams, rock rip-raps, sand bags, maintenance of normal slopes with vegetation or application of soil cements on steeper slopes and construction or expansion of drainage. Other methods include dykes, dams, retention basins or detention.

Why is it called the Plimsoll line?

Samuel Plimsoll (10 February 1824 – 3 June 1898) was an English politician and social reformer, now best remembered for having devised the Plimsoll line (a line on a ship’s hull indicating the maximum safe draught, and therefore the minimum freeboard for the vessel in various operating conditions).

What is the purpose of load line?

The purpose of the load line is to ensure that a ship has sufficient freeboard (the height from the waterline to the main deck) and thus sufficient reserve buoyancy (volume of ship above the waterline). It should also ensure adequate stability and avoid excessive stress on the ship’s hull as a result of overloading.

How to calculate the floodable length of a line?

The calculations can be repeated for a series of waterlines tangent to the margin line at different positions along the length. This will lead to a curve of floodable length as in Figure 3.35. The ordinate at any point represents the length which can be flooded with the centre at the point concerned.

What is the product of floodable length and factor of subdivision?

The permissible length is the product of the floodable length and the factor of subdivision. The factor of subdivision depends upon the length of the ship and a criterion of service numeral or more simply criterion numeral.

Why does the floodable length of a ship decrease?

This numeral represents the criterion of service of the ship and takes account of the number of passengers, the volumes of the machinery and accommodation spaces and the total ship volume. It decreases in a regular and continuous manner with the ship length and factors related to whether the ship carries predominantly cargo or passengers.

Which is the best way to calculate damage stability?

1. Floodable length and factor of subdivision This is an old approach but it is still important to discuss this because this approach lays the foundation to understand damage stability. In this approach, the number of subdivisions required is calculated by knowing the floodable length along the ship.