how to calculate stability of semi-submersible vessel?

[ycl229]

your discuses are useful to me!

[sirhamid]

Originally Posted by manon

hello everybody,

i now have a problem about calculating the stability of a semi-submersible plat form supply vessel ( twin hull ). it is priniciple dimension Lbp = 70 m, beam per hull = 10 m, gap between two hulll = 18 m, platform height = 21 m, hull depth = 5m. light condition depth is 2.7m and submersed condition depth is 12.5 m.

please help me to calculate the stability of this vessel manually. i cant calculate with my software (hydromax), because, there has no criteria that could fully support this vessel while calculating.

thank you very much

hi dear
you can model your vessel on Rhino and loft surfases on this,so then save as "igs" format for maxsurf usage.

i can do this for u.send me your cad model,for this.

[manon]

thanks for your interest sir, but i already have the maxsurf model. but the problem occured while calculating the stability, becasue i cant understand which stability criteria in hydromax will be appropreate for such type of vessels.

[sirhamid]

Originally Posted by manon

thanks for your interest sir, but i already have the maxsurf model. but the problem occured while calculating the stability, becasue i cant understand which stability criteria in hydromax will be appropreate for such type of vessels.

oh ,ok
i can send you the modify MODU code on hydromax criteria,but you may be wait about some day.
at the last night,i had a same project on iranian MODU "shahid rajaee" about the modifing the stability booklet on new inclining experiment.i think you have problems same as i had.

[sirhamid]

first read this file:
OFFSHORE STANDARD
DET NORSKE VERITAS
DNV-OS-C301

[manon]

sir, the problem is, this vessel is not a drilling unit, this is actually multi purpose semi-submersible unit...........can i use the modu code? if so, i already have the GL class codes.

i a have tried to calculate stability with
1.The Health and Safety Executive, Offshore Installations: Guidance on Design, Construction and Certification, Fourth Edition with amendments, 1993.
2.CODE FOR THE CONSTRUCTION AND EQUIPMENT OF MOBILE OFFSHORE DRILLING UNITS, 1989
.......again, if you could please can send me the MODU criteria for hydromax, it will also be very helpful.

thank you very much

[sirhamid]

yes manon,you could use that code.for the semi-sub vessels ,the rules same used for this types.
but on your calculatio,U must be provide the rigging forces on vessel for meassure the righting arm effect,like you calc the wined force and so on.

[sirhamid]

this can be help U:
Review of issues associated with the
stability of semi-submersibles