# Will the stability significantly decrease？

Discussion in 'Stability' started by sun, Oct 16, 2018.

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### sunJunior Member

A ship grounded on beach，the ground point in bulb bow， so will the stability significantly decrease？
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I searched some textbook，but i do not find the mathematical formula about it

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### Mr EfficiencySenior Member

Impossible question without a lot more info, I would think.

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### TANSLSenior Member

Make a composition of the forces acting on the ship (taking into account that the reaction of the ground is exerted at the point of support and that the ship turns around that point) and you will understand what is happening. It is about applying elementary physics and the composition of forces. There are endless books (and perhaps videos) that explain it.
You should spend more time with your teachers and with the books that chatting in this forum,

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### sunJunior Member

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### sunJunior Member

website is uploaded

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### sunJunior Member

Thanks!

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### sunJunior Member

Who can help me download a paper（The effects to a container ship due to soft grounding），i have no way

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### TANSLSenior Member

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### messaboutSenior Member

An empirical lesson was learned one day when I was a beginning kayaker. After a pleasant paddle with my paddling buddy in another kayak, I ran the bow of my boat up on the landing ramp....only a foot or two of the 16 foot kayak. I promptly overturned, fell into the water and was thoroughly embarased. My paddling friend thought it to be hilariously funny.

I probably have the ability to calculate the difference in height of the center of buoyancy and the center of gravity of a boat, kayak or other floating object. That was not at the front of my attention that day. You can be sure that I never made that mistake again.

Bottom line is that if a bow bulb is launched onto a beach the metacentric height of the system will almost surely change unfavorably. But that depends somewhat on the cargo of the vessel. If the cargo was liquid in which the change of pitch sent the weight and resulting CG of the cargo aft, sufficient to lower the aft section into the water,then it is possible that the lifted bulb would not promote a capsize. Plenty of variables here, but not a usefully analyzed variable in a kayak or in a tanker or other ship that does not have a tendency to transfer its cargo in concert with the pitch angle.

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