# Calculate the Lightship weight

Discussion in 'Hydrodynamics and Aerodynamics' started by Ghost Boy, Feb 20, 2020.

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1. Joined: Oct 2019
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### Ghost BoyJunior Member

Hello,
I have lines plan. I wanna calculate lightship wight. Can anyone refer me any books or article or method? Thanks in advanced.

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### TANSLSenior Member

Allow me please a previous question, do you know what lightship weight is?

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### Ghost BoyJunior Member

The lightweight is the displacement without cargo, fuel, lubricating oil, ballast water, fresh water and feed water, consumable stores and passengers and crew and their effects, but including liquids in piping.

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### jehardimanSenior Member

Does the lines plan state or show lightship draft and trim?

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### TANSLSenior Member

Well, since you already know the most difficult, the rest is easy, add, multiply and divide. It is about putting a list with all the weights and their CoG and adding and multiplying.
One of the important items is the weight of the hull and the superstructure. To calculate it, you should calculate the scantlings.
Another important weight is that of the main and auxiliary engines. Calculate the necessary power and consult, in manufacturers' catalogs, the weights of the engines.
You define all the equipment that the ship will carry and, likewise, check the suppliers' catalogs.
You estimate the amount of pipes and wires and calculate weights and cog. And the same for all items.
To the total you get, you add a 25% margin and you're done.

#### Attached Files:

• ###### Weights Estimation.xlsx
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6. Joined: Oct 2019
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### Ghost BoyJunior Member

Thank you sir for your file. Can you please suggest me any books or any article?

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### gonzoSenior Member

You don't really need a book. Add the weight of everything, hull plating, framing, decks, piping, machinery, etc.

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