# What is the meaning of trim equilibrium for a ship?

Discussion in 'Boat Design' started by xichyu, Apr 12, 2016.

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### xichyuJunior Member

What is the meaning of trim equilibrium for a ship?

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### DCockeySenior Member

Is this a question from an assignment or test?

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### xichyuJunior Member

I am a student， I am learning ship theory now

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### gonzoSenior Member

Do you mean how to calculated the trim of the vessel as you change the load? That is, where is the waterline?

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### xichyuJunior Member

I think so
Thanks

6. Joined: Apr 2015
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### HeimfriedSenior Member

I don't know if it would be helpful, but may be. Try it, if you want.

You can play with the centers of gravity and bouyancy, shift load and look at the change of trim and heel.

http://www.bootsphysik.de/rechner/bootx.php

First click button "English" at the first line right.
Then "show legend",
input at "mass to relocate" 300, TAB
input at "longitudinal" 300, TAB
click "apply relocation"
the red dot (CG) has moved a bit

click "find equilibrium" (bottom)
shown trim angle is 0.5 deg.

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### xichyuJunior Member

Thanks！
Can I input a model made by myself？

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### HeimfriedSenior Member

Sorry, you can't.

(But if you are able to provide a csv-file with appropriate data of a boat hull, I could install it.)

There is an other site with a few different frames to choose.
But it deals only with heel, not with trim.

http://www.bootsphysik.de/rechner/bootxp3.php

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### xichyuJunior Member

If it can not conveniently input a model. I do not think it can be used extensively

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### HeimfriedSenior Member

You are right,
but the site is not to calculate the behaviour of user's boat.

It is to show exemplary the things about stability, heel and trim.
It is to learn about and to develop a sense to boat hydrostatics.

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### xichyuJunior Member

I got it, Thanks all the same!

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