Transverse metacenter (MT)

The transverse metacenter M is the point where the vertical line through the center of buoyancy of a slightly heeled ship crosses the centerline, the apparent pivot for small transverse heel. Its height above the keel is KM = KB + BM, with the metacentric radius BM = I_T / V, the transverse waterplane second moment of area over the displaced volume. The metacentric height GM = KM - KG then measures initial transverse stability, and the IMO 2008 IS Code requires a corrected GM of at least 0.15 m for most ships. The concept holds only for small angles, since at larger heel M moves along the metacentric evolute.