Split Hopper barge stability

I have some doubts regarding the stability analysis of split hopper barge.I have auto hydro software with me.

I am planning to analysis below loading conditions

1.Lightship condition (Hopper closed and open)

2.Fully loaded condition

If anyone is expertise in split hopper barge stability,Please revert to below queries,

What all conditions need to consider during stability analysis?
Do we need to calculate hydro statics particulars for Hopper-open and closed conditions?

 

If you need it, I can prepare some notes on how to proceed with these calculations.
Meanwhile you can find information here (maybe there is an updated version of this paper):

Title: Stability, Subdivision and Load Line Standards
Number: TP 7301 E
Date: 1975
Details: Marine Safety Directorate
Transport Canada
Ottawa
​

You can also find information in the Bureau Veritas regulations (and probably in other CSs).

Answering your questions :
"What all conditions need to consider during stability analysis?" : It must study the lightship condition, open and closed and the condition of maximum load, with different densities of load. The ship must comply, surely, with some regulations, CS or administration of the flag country. It will specify if there is any special load condition to study.
"Do we need to calculate hydro statics particulars for Hopper-open and closed conditions?": Yes, of course

 

Hope this paper could help you.
If you detect errors (apart from the orthography and / or grammar, which I hope you forgive me) it would be very interesting to discuss them.

 

Thanks TANSL

 

Hi,

We are checking the stability vessel at loading conditions with different cargo densities in hopper closed condition and lightship stability during open and closed condition.

This is my understanding.

Why we are not checking the stability during the outflow of cargo to sea and inflow of seawater to hopper?Is there any method to check?

Any other important factors do we need to consider during calculation except the location of spilling point?

Please advise.

 

The outflow of charge to sea is considered instantaneous and for that reason, in my opinion, it is not necessary to study stability at that moment. What has to be taken into account is always the existence of free surfaces when there is water (besides the products of dredging) in the pitcher. You should check various loading situations until you are sure that you have studied the most unfavorable ones.
In the most normal load conditions there is a certain load, whose center of gravity changes with the heel of the boat and, in addition, a certain amount of water which increases the height of the CoG and produces the effect of free surfaces. Both effects add up to reduce stability.
You also have to study the stability when the bottom doors are open, the hoppers are in contact with the sea and, therefore, there is a decrease in buoyancy. The various combinations of open / closed doors must be studied.

 

Thanks TANSL

 

Can i any one advise which all points to be considered as floooding points of split hopper barge.Do i need to consider hoppe coaming edges?

 

Yes.

 

Hi TANSL, Thanks for your prompt reply.Do u have any reference document for stability calculation of split hopper barge apart from the document one which you sent earlier.

I got one reference document. As per that, need to model 3 hulls as below.

1. Hull-Hopper closed condition
2.Hull- Hopper open to sea
3.Split conditon

But i didnt understand what is meant by hopper open to sea. It is same as spli condition right?or the hopper open to weather?

Please advise if anyone has good knwoldge about this.

Regards
Adarsh

 

When a bottom door is open, partial flooding of the pitcher occurs, as seen in the picture, the hull loses buoyancy; stability in that condition must be studied.
For this, it is best to make a 3D model of the hull and, if the model is a solid model, better.