What is VEF (Vessel Experience Factor) ?

The VEF is a factor to account for residual inherent measurement imprecision associated with ships’s calibration and residual random measurement variations (both ship and shore).

The VEF is a computation of the history of the Total Calculated Volume (TCV) loaded by the vessel adjusted for OBQ or ROB, compared with the TCV of shore measurements, typically a Bill of Lading in order to compute a load port VEF for the vessel.

The VEF should always be used by the vessel to assess if the Bill of Lading quantity is reliable. It may also provide an indication of potential shortages on outturn at discharge port(s). It is essential that the ship’s loaded quantity is correctly determined from measurements made prior to and on completion of loading. It is also essential that the ship’s figure and the Bill of Lading quantity are determined by consistent calculation procedures, with particular reference to the applied VCF. VEF can facilitate more accurate determination of vessel quantity for custody transfers also when necessary and where warranted.

Following factors must be taken into account when calculating VEF:

• VEF is not applicable to individual tank volumes
• Quantities shall be expressed in either barrels or cubic meters at standard temperatures, but shall not be combined. DO NOT USE QUANTITIES IN MT OR LONG TONS.
• VEF used to calculate Ship’s quantity at load port MUST be the VEF which is used to calculate the vessel’s quantity at Discharge port. A different VEF must not be calculated for the same voyage.
• A minimum of five qualifying voyages are needed to calculate VEF, however, a larger number is always desirable. DSM Form for VEF uses last 20 qualifying voyages which is usually the accepted industry standard.
• A ‘Qualifying Voyage’ is a voyage that is within + or – 0.0030 of the average ratio of all voyages (Pls refer to Charter Party Terms) listed. (as an example, if the average of all voyages listed is 1.00105, all voyages within the range from 0.99805 through 1.00405 would qualify ).

Following voyages are excluded:

1. All voyages prior to any structural modification which affected the vessel’s cargo carrying capacity.
2. Load or discharge data where shore measurements were not available or Bill of Lading figures were based on Ship’s measurements.
3. All voyages involving ship-to-ship lightering operations.
4. The first voyage after dry docking.
5. Voyages where the vessel has loaded several parcels or Voyages where vessel only part loaded to less than 75% capacity.

Get free VEF excel sheet below in downloads section for training purposes.

An erroneously calculated VEF results in inflating or deflating cargo quantity loaded on board the vessel and giving cargo interests an inaccurate representation of “vessel loaded” quantity.