# How can we solve the ground reaction?

Discussion in 'All Things Boats & Boating' started by xichyu, May 1, 2016.

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### xichyuJunior Member

A ship stranded on a shoal，and part of hull under sea mud. The weight of ship
is G. If we only know the shiplines，other details can not be obtained. How can
we solve the ground reaction?

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### TANSLSenior Member

G = Ground reaction + thrust due to the volume of displaced water.
Sum of moments of the three forces = 0. It will be more difficult to determine.

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### BarrySenior Member

I think that it will be a little more complicated than the above due to the fact that the mud would provide some buoyancy.

ie if the boat was grounded on rock, it would be quite simple if you knew the amount of water displaced.
But in this case if the mud is soft then there will be pressure/buoyancy on the hull acting below the mud to water interface.

So if it is quite soft then you would have to determine the amount of mud that is also displaced and determine buoyant forces using the density of the mud

Alternatively if you had scoured out the profile of the hull into the mud to some level and let the boat strand into the scoured out profile, you would still get a buoyant effect from the volume of the water displaced by the hull below the mud level if the boat hull surface was wet.

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### gonzoSenior Member

It would largely depend on the qualities of the mud. You should treat it like a semi-solid.

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### TANSLSenior Member

You will agree with me that in the "Ground reaction" is included buoyancy due to mud.
On the other hand, with the data that the OP gives us, it seems quite impossible to draw any meaningful conclusion.

What is very important is to know that: "It would largely depend on the qualities of the mud". With that and a fishing rod, we can solve the problem.

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### xichyuJunior Member

Yes，I am considering to learn Soil Mechanics

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### xichyuJunior Member

TERZAGHI EQUATION may solve the problem

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### xichyuJunior Member

In the initial stage， we can assume the same qualitiy of the mud

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### gonzoSenior Member

The Bowles correction could be used giving Dw=0. That is an interesting approach

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