Question about damage stability

[yuyewuyuconan]

HAlf years ago i began to use Compass(a chinese class societies' software ).I think many friends dot konw it ,but the way of the damage calculation is the same .IN compass you should putin :
Ls,ds.dp.......Lgp(center of gravity distance from ap when d=dp).Lgs.Vgp(center of gravity distance from BL when d=dp),Vgs...
dp=d0+0.6(ds-d0),
when d=dp
how can i konw Lgp&Vgp
wheather i can thing the ship is no trim Lgp=Lbp(i can get Lbp in hyd)
but the Vgp is not know ...any friends can help me ? thanks!

[Martijn_vE]

Originally Posted by yuyewuyuconan

how can i konw Lgp&Vgp
wheather i can thing the ship is no trim Lgp=Lbp(i can get Lbp in hyd)
but the Vgp is not know ...any friends can help me ? thanks!

I assume you have a design you're working on. But it's pretty much useless to asses the damage stability in a stage of your design where you don't know the VCG.
Are you working on probabilistic damage stability?
In that case VCG is initially calculated from a loadcase at design draught.
After the first run the GM is reduced to a minimum in a number of calculations so you carry as much cargo as possible throughout the ships life.

If your calculating deterministic damage stability the VCG is already known.

[yuyewuyuconan]

HI Martijn_vE
i am working on probabilistic stablilty.
why you think that loadcase is calculated?FOR example :a oil tanker(only carry one kind of liquide) so i only should calculate 6 loadcases(In CCS rule )
1.FLD 2.FLA 3.PLD(one team of tanks _max free surface ) 4 .PLA 5.BD 6.BA.IN these loadcases on one is d=dp ,dp is not design draft.

[Martijn_vE]

It make sense to first calculate the loading conditions prior to check the probabilistic damage stability. It will give you a good indication for the initial VCG's needed for the damage stability calculations. After this initial guess you can lower or raise your VCG's depending on the attained index.

[yuyewuyuconan]

Thank you！