HomeCalculatorsRequired Section Modulus

Required Section Modulus

Minimum hull-girder section modulus from total bending moment and steel grade allowable stress.

StructuralIACS S11
Allowable stress
175.0N/mm²
Required section modulus
19.429
Formula, assumptions, and limits

IACS UR S11 allowable bending stress σ_perm = 175 / N (N/mm²), where N is the material factor. Higher-tensile steel lowers Z_req but requires more careful fatigue design (UR S11A on container ships).

Symbol legend

SymbolMeaningUnitSource
Absolute still-water + wave bending momentskN·mloading computer / UR S11
Allowable bending stressN/mm²IACS UR S11
Minimum required section modulusresult