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Reserve Buoyancy & Its Importance?

Reserve buoyancy is the potential buoyancy of the ship and depends upon the intact and watertight volume above the waterline. When the mass is added to the ship or buoyancy is lost due to bilging, the reserve buoyancy is converted to buoyancy by increasing the draught.

 If the buoyancy exceeds the reverse buoyancy the vessel will sink.

Importance of Reserve Buoyancy:

Reserve buoyancy is important for the vessel's safe operation at sea. Think about the following example. You have set off for a day's fishing in a small fishing boat. You set off yourself with a small amount of gear from the moorings. 

The boat is lower in water now and doesn't get up on the plane quite so easily. Nevertheless you head out and have a good fishing day, so good that the boat is filled with fish. On the way back you have to travel very slowly because the boat is very low in water now and you are worried about seas being shipped over the side.

What has happened is that you have reduced the reverse buoyancy of the boat, The more you load the boat the greater is its displacement, the more it will sink in the water, the less reserve buoyancy it will have.

Every boat must have sufficient reserve buoyancy to operate safely, do not overload your vessel. Commercial vessel have a load line assigned to them and it is offence to proceed to sea with load-line submerged.

This line sometimes know as the Plimsoll line, after Samuel Plimsoll who campaigned heavily for the safe loading of ships in 1870s.

Reserve buoyancy, is linked pretty closely to the free-board of the vessel, the height above the waterline of the uppermost continuous deck, or in a small boat to the gunwale.


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