What Is the Ship Transverse Metacentric Height (GM) & Stability Calculator?
Metacentric height (GM) is a measurement of the initial static stability of a floating vessel.
How Does the Ship Transverse Metacentric Height (GM) & Stability Calculator Work?
Computes the height of the transverse metacenter KM = KB + BM, then subtracts the center of gravity KG.
Ship Transverse Metacentric Height (GM) & Stability Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
GM = KB + BM - KG, quad GZ = GM sin( heta)
Transverse metacentric height and righting arm for small heel angles.
How to Use the Ship Transverse Metacentric Height (GM) & Stability Calculator
- Input vertical positions of buoyancy KB, gravity KG, and metacentric radius BM.
Step-by-Step Example Calculation
Cargo Vessel Ballast Condition
Input Values:
keelToBuoyancyKbM:3.2
transverseMetacentricRadiusBmM:4.8
keelToCenterOfGravityKgM:6.5
heelAngleDeg:5
Worked Steps: Metacentric height GM = 1.50 m (Stable); restoring righting arm GZ = 0.131 m at 5° heel.
Understanding Your Result
Positive GM (> 0.5 m) indicates stable equilibrium; excessively high GM causes abrupt, uncomfortable rolling.
Factors That Affect the Result
- Cargo loading height raises KG; free liquid surface effect in slack tanks introduces a virtual reduction in GM.
When Should You Use This Calculator?
- IMO Intact Stability code compliance, cargo loading computer calculation, and drydock stability checks.
Assumptions & Limitations
- Valid for small heel angles (under 10–12°); large angles require full GZ cross-curves of stability.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard IMO intact stability initial hydrostatics formulation.