# MODU table

Discussion in 'Class Societies' started by ejim, May 23, 2010.

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### ejimNot Really Junior Member

As per subject matter, what is MODU table? and where can i get it?

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### RAraujoSenior Member - Naval Architect

Can you expand? Are you talking about Mobile Offshore Drilling Units?

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### conceptiaNaval Architect

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### ejimNot Really Junior Member

i need to solve a question that need to use this formula:
Wind force, Fv = 0.5 x Cs x Ch x air density x V^2 x Aw
where, Cs & Ch are factors (MODU table)
Aw is projected area above MSL

so then, where should i refer this so called MODU table in order to get the value for Cs and Ch?
this is the only way i can explain

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### conceptiaNaval Architect

Cs is the shape coefficient, and Ch is the height coefficient. Normally the shape factor value could be determined by the shape of the structure.(it will be different for tubular members, cylinders, rectangle sections etc) This is given in the MODU rules.
The same way velocity of the wind increases along with the height ASL. The normal wind speed we consider is for 10 m ASL, thus we need to give in a correction factor for this difference. As generalizing we use the seventh power law.
In actual calculation, wind load for individual members are calculated and added. At this time the Cs and Ch will differ for each member. This correction will be provided to you in the MODU table.
Hope it is clear..

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### ejimNot Really Junior Member

conceptia, thanks for the kind reply, but I have some more questions.

what is difference between shape coefficient and block coefficient?

what is the seventh power law then?

and unsolved question yet so far : where should i refer/find this so-called MODU table?what is "MODU" stand for?why i can't get it by googling?if it is already there,what the exact word should i type to search?

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### daiquiriEngineering and Design

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### RAraujoSenior Member - Naval Architect

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### ejimNot Really Junior Member

Dear daiquiri & RAraujo,

Wow! a big THANK YOU for u guys! finally solved my problem!

PAGE 21 is what im searching for

again,thank you very much!

regards,
ejim

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### conceptiaNaval Architect

haha.. ejim what do you mean "not really junior member". Anyways you got your doubts cleared, right?

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