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 Boat Design Forums Max VCG

#1
04-24-2012, 06:56 AM
 JKKING Join Date: Apr 2012 Rep: 10 Posts: 2 Location: Singapore
Max VCG

Is max VCG Permissible for Intact condition is always smaller than Max VCG permissible for Damaged condition?
Anybody have idea?
#2
06-05-2012, 08:54 AM
 Pascal Warin Junior Member Join Date: Feb 2012 Rep: 38 Posts: 62 Location: Paris
These values have no relationship because they apply to different conditions (intact vs. damage) and criterions are different.
It is not usual to calculate damaged max VCG except when loading condition cannot vary much. Depends on vessel type.
#3
06-25-2012, 12:44 PM
 TANSL Senior Member Join Date: Sep 2011 Rep: 119 Posts: 475 Location: Spain
Quote:
 Originally Posted by Pascal Warin These values have no relationship because they apply to different conditions (intact vs. damage) and criterions are different. It is not usual to calculate damaged max VCG except when loading condition cannot vary much. Depends on vessel type.
When calculating the stability after damage, in passenger vessels, you need to calculate the heeling that occurs when all the passengers are crowded into a ship's side. This angle of heel depends directly on the value of VCG. So ALWAYS, ALWAYS, is necessary to calculate the VCG.
The maximum value of VCG that allows the ship to meet all the criteria of stability is indeed different for the intact ship condition or damaged vessel.
#4
06-25-2012, 12:51 PM
 Pascal Warin Junior Member Join Date: Feb 2012 Rep: 38 Posts: 62 Location: Paris
That is not true because the effect of passenger crowding is calculated AFTER damage thus there is no need to calculate allowable VCG.
#5
06-25-2012, 01:10 PM
 TANSL Senior Member Join Date: Sep 2011 Rep: 119 Posts: 475 Location: Spain
Quote:
 Originally Posted by Pascal Warin That is not true because the effect of passenger crowding is calculated AFTER damage thus there is no need to calculate allowable VCG.
Do not say it's not true, but you're wrong. Thank you.
Of course the calculation must be done after damage but starting from the posción of the weights with the intact vessel. Calculate the maximum value of VCG may or may not be necessary. You have to study the worst positions in which you can place the passage. (Which, in a sense, is equivalent to calculate the maximum possible value of the VCG). In any case the c. of g. height for the ship, passengers, and any other weight ALWAYS has to be calculated.
With all due respect,
Ignacio López
#6
06-26-2012, 11:47 AM
 Pascal Warin Junior Member Join Date: Feb 2012 Rep: 38 Posts: 62 Location: Paris
The sole case you may perform damage stability allowable KG is for "old" SOLAS where there is no run-off calculation thus every compartment is deemed empty regardless of its actual content.
And, of course, effect of passenger crowding and/or survival craft launching is only one amongst other criterions.