| Product(s): | MAXSURF Stability |
| Version(s): | all |
| Area: | Limiting KG |
When doing Limiting KG Analysis, result comes up with negative VCGs.
There is nothing wrong with -ve VCG to pass the criteria – basically means the vessel is quite unstable geometrically at low displacement – it’s the angle of max GZ criterion that causing the failure.
The best thing to do is make a loadcase with one of the lower displacements with the results you are questioning and run a large angle stability analysis with the same settings as you have for Limit KG. Then look at the GZ curve to see whats happening.
How to Calculate Maximum VCG with MAXSURF Stability (Youtube Video)
Troubleshoot Maximum VCG Calculations in MAXSURF Stability (Youtube Video)
The limit KG is found by assuming that lowering the VCG will make it more likely to pass the stability criteria. Whilst this is generally true of all criteria, there are some criteria and some geometries where this is not the case (for example angle of deck edge immersion does not change predictably with change of VGC for the general case; the same can be true of Angle of Max GZ)
You can also add additional sections in the hull. Setting up different heel angle steps can have a large influence over Angle of Max GZ based on your criterion.
Stability Criteria: how to use, create and modify