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Vessel Experience Factor (VEF) Calculator

Marine Loss Control · API MPMS Ch. 17.9 / IP HM 49

Vessel Experience Factor (API MPMS Ch. 17.9)
Enter the vessel-measured and shore-measured Total Calculated Volume (TCV) for each voyage (most recent first, up to 20). The calculator rejects major errors, qualifies voyages within ±0.30% of the mean, and returns the VEF from a minimum of five qualifying voyages. Defaults are the standard's Appendix C example.

Voyage History

#Vessel TCVShore TCV

Use consistent units for all entries (bbl, m³, or tonnes). Exclude post-drydock and onboard-only voyages per §8.3.

Formula

VEF = Σ Vessel TCV / Σ Shore TCV
ratio = Vessel TCV / Shore TCV (5 dp)
Major error: ratio < 0.98 or > 1.02 (rejected)
Qualify: ratio within mean × (1 ± 0.0030)
Valid if ≥ 5 qualifying voyages

Standards & References

  • API MPMS Ch. 17.9 / IP HM 49
    Vessel Experience Factor (VEF) — §8 data qualification, §9 calculation
  • API MPMS Ch. 17
    Marine Measurement

Engineering Notes

  • Most recent first: list voyages newest to oldest, up to 20.
  • Major errors (>2%) are rejected before the mean.
  • Minimum 5 qualifying voyages for a valid VEF.
  • Application: VEFL for loading, VEFD for discharge; applied to vessel TCV.

Frequently Asked Questions

What is a Vessel Experience Factor?

A vessel-specific factor = total vessel TCV / total shore TCV over qualifying voyages, applied to the ship's measured volume for loss control and custody reconciliation (API MPMS 17.9).

VEFL vs VEFD?

VEFL is computed from loading voyages, VEFD from discharge voyages. Same algorithm; only the ratio source differs.

How many voyages are needed?

A minimum of five qualifying voyages (up to the most recent 20). Major errors (ratio outside 0.98–1.02) are rejected and voyages outside ±0.30% of the mean do not qualify.