# tank capacity plan of a passenger vessel

Discussion in 'Boat Design' started by appusree888, Aug 19, 2014.

1. Joined: Jul 2014
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### appusree888Sreenath

Excuse me...i have a doubt ...can anybody help me? actually am doing tank capacity plan of a passenger vessel.so there i did all the things except on.i took LCG from aft end,VCG from baseline,TCG from centre line,capacity calculated by L*B*D of te tank...and i saw a column named weight,actually whatz that weight stand for? is it weight of liquid which it contains? and how to find it

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### TANSLSenior Member

It is the weight of the liquid in the tank, fresh water, salt, diesel oil, hydraulic oil, gray water indeed ...
Not to be found anywhere. You are the designer. Only you can know what liquid is in each tank and therefore the density that you should apply.

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### appusree888Sreenath

so its only needed to calculate the mass of diesel in fuel oil tank by volume of tank x density of diesel and for fresh water in fresh water tank by volume of tank x density of fresh water...right??

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### JRDSenior Member

Density of liquid is often referred to as specific weight, so it would be reasonably logical to have this in conjunction with the volume measurement to obtain a known mass at each relative location.
However it might also be expecting you to input the actual weight (mass) of the contents, in addition to the dimensions. If you can't tell which it should be, then you could end up with wildly incorrect numbers.

As I think Tansl has alluded to, but not said directly, you need to understand your employers calculation procedures.
As with all facets of engineering and science there can be a number of ways to get the same answer, depending on how you put the parts together. But only as long as the methods are all based on a fundamentally correct theory and data.
If your system is computer based, then you will need enquire as to the correct units of measurement to use, unless you can check the calculations and understand exactly what they mean.

Ships tankage can represent a significant proportion of the displacement, trim and stability numbers, so if you need this kind of help you should be consulting a qualified NA and probably not relying on advice solicited on an internet forum.

BTW - Not a NA here, just an engineer on terra firma with a keen interest in boats and their design.

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### appusree888Sreenath

thank you Tansl and JRD

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