# Ballast calculation

Discussion in 'Stability' started by muthubd14, Mar 21, 2014.

1. Joined: Mar 2014
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### muthubd14Junior Member

HI. In the design stage of a 215m vessel, how do i ensure that the ballast volume provided is sufficient enough for all operations of vessel.
For eg: whether provided ballast is sufficient for amphibious operation like lcm launching, docking and during lightest sea going condition.. Is there any emphirical formula for ballast capacity determination ?? ..Any non-software methods to evaluate this ???

2. Joined: Oct 2008
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It is a simple matter of arriving at a loaded condition for each scenario, such as full load, arrival, docking etc etc. That is a series of displacements and LCG values. From this you look at the hydrostatics. Is the draft in the set condition where you need for your operation?...you can then work out what draft you do need and thus how much ballast (as displacement) you need to sink/trim the vessel to get the required draft and trim from the hydrostatics.

You just need a set of hydrostatics, the loading conditions with the deadweight locations of LCG and weight for each item in each set condition (such as fuel or cargo or passengers)and the initial Lightship data of the vessel..and off you go

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### gonzoSenior Member

One important thing to also consider, are the dynamic loads. If you are launching LCMs, there will be a considerable component cause by moving the heavy load.

4. Joined: Mar 2014
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### muthubd14Junior Member

Thank you......can yu pls elaborate on wat designer does to cater for component caused by moving LCM..??

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