# Questions about Design loads in DNV Standard for Certification of Craft 2.21

Discussion in 'Class Societies' started by Aryo Baskoro, Nov 29, 2017.

1. Joined: Nov 2017
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Hello, my name is Aryo

I would like to ask you some questions about calculating the sea pressure based on DNV Standard for Certification of Craft. To calculate sea pressure there is longitudinal distribution of sea pressure (klb) there is x Lh to be known (Ch. 4 Sec. 2) . Does anybody know what x and Lh definitions?

Thank you

Last edited: Nov 29, 2017
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### daiquiriEngineering and Design

Are you sure that you are using the updated version of DNV-GL rules?

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### RAraujoSenior Member - Naval Architect

Hi Aryo,
Without having checked the standard I would say that Lh is the hull length (as defined in the standard) and x Lh (I think it shall be x/Lh) is the non-dimensional longitudinal location (0 for the extreme aft and 1 for the extreme forward ends of Lh)

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Welcome Aryo.
If you don't know the answer to this, then perhaps you should let someone else do your design for you. It should be self explanatory.

x = part - length of hull
Lh = hull length.

So for example, if your hull is 30m in length, and you wish to check the value of K at a speed-length ratio of 4, at amidships, then the value is simply 15/30 = 0.5. Thus 0.5 gives you a value of K of roughly 0.75

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### AlikSenior Member

1. This standard has been replaced in 2016 by DNV-GL ST 0342.
2. For design loads, both 0342 and 2.21 use older version of ISO12215-5.

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