# Coefficient of Scantling

Discussion in 'Boat Design' started by Annode, Apr 3, 2020.

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### Boat Design Net ModeratorModerator

Note: unless this thread starts to go in a more positive and productive direction, it will be closed. Will give it a few more posts to see if it becomes productive; if it continues like it has on the last page, the thread will be closed.

rxcomposite, Ad Hoc, BlueBell and 2 others like this.
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Thank you moderator. This thread has exhausted its usefulness

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### mc_rashJunior Member

I read this thread now - nearly one year later - and I wondered about estimating the weight by using class rules. You could calculate loads based on the rules and with the known loads you could determine the dimensions incl. spacing and weight of the necessary framing in a midship section. Then it is possible to calculate (not real exact but estimated) the total weight of the framing by using the midship frame and maybe prismatic or block coefficient. Or you may want to draw each frame in the hull with the right spacing so you'll get the dimensions of the section where you put in the frame.
For myself I just would follow the design spiral (the framing weight is at this early stadium not important in my opinion).
The methode from above is way to much at this moment.

At the end I wanna say, there's no right way to go. But if experienced people let you know their experience you should follow them.. Weight depends to much on size, kind of ship/boat/..,... so that you can't define THE COS.

Bye

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### TANSLSenior Member

The normal thing is to calculate the scantlings for at least 3 cross sections of the ship as well as a typical bulkhead. With this, you already have enough information to obtain an approximate weight of the structure, in most cases.
When you have a 3D model of surfaces, which gives you the m2 of each one, this data can be used to determine the weight of the lining and cover plates. This adds more precision to the above calculation.

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### gonzoSenior Member

It would be the square of the length of rope tied three times around the longest part of the boat and touching the bottom of the bay.

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### TANSLSenior Member

I have no idea what that number could mean. I suppose that the formula is a "recipe" to obtain something easily and, if it is so (if it is not, you excuse me), the truth, in our time, with the amount of design tools available to the designer, access To information from other ships, to turn to recipes from 60 years ago or more, it seems unprofessional. It could be good for beginners, but it is not advisable. But of course, each one uses the tools that his knowledge allows him.

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### Alexander Peter BromleyJunior Member

mc_rash and TANSL like this.

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### TANSLSenior Member

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