b) These shall be the most recent voyages available and listed in chronological order; do not use the current voyage.
5. If at least five qualifying voyages remain, calculate the VEF from the qualifying voyages as follows:
14.2.3.1 Primary Method - Rejected Voyages
The following voyages shall not be used in the calculation: a) Gross error voyages. i.e. voyages where the Vessel Load Ratio (VLR) or Vessel Discharge Ratio (VDR) is less than 0.98000 or greater than 1.02000. b) Voyages where only vessel tank measurements were available (i.e. vessel-to-vessel transfers, active shore tanks) except where quantities are determined onboard FPSOs using meters in accordance with globally recognized standards. c) All voyages prior to any changes to measurement equipment, tables, vessel’s structure, or other changes requiring the issuance of new capacity tables. No voyages shall be excluded beyond the reasons given above, unless specifically agreed by all interested parties. 14.2.3.2 Primary Method - Calculation of a VEF 1. List the data for as many recent voyages as are available, up to a maximum of 20 voyages. For VEF Load (VEFL), use only load data and for VEF Discharge (VEFD) use only discharge data.
c) Quantities should be combined for multiple grades on the same voyage.
a) Sum the vessel quantities and shore quantities.
d) Units shall be consistent on the entire form, i.e. Bbls, m3, metric tons, long tons, etc., and rounded to the nearest whole number. If units are mixed, then the alternate method shall be used. 2. Calculate individual vessel/shore ratios for each voyage, rounding to five decimal places. NOTE: When the figure to the right of last place to be retained is five or greater, the figure in the last place to be retained should be increased by one. If the figure to the right of the last place to be retained is less than five, the figure in the last place retained should be unchanged. 3. Next exclude all rejected voyages from the calculation (see section 14.2.3.1). Calculate the mean vessel/shore ratio from the total remaining quantities rounding to five decimal places.
b) Divide total vessel quantity by total shore quantity.
c) Calculate and round to four decimal places to produce the VEF.
14.2.4 Alternate Method
The alternate calculation method employs a statistical method for establishing the reliability of individual load (or discharge) ratios and for estimating the confidence limits (probability = 90 %) for the range of acceptable values. Data from a minimum of five qualified voyages is needed to calculate a VEF. In this method, only vessel load ratios or vessel discharge ratios, which are statistically significant at the 90 % probability level, are included in the calculation of the VEF. a) The Inspector is responsible for calculating the VEF. List the data for as many voyages as are available, up to a maximum of 20 voyages.
4. Then exclude all disqualified voyages. Disqualified voyages are:
A voyage that is eliminated because the Vessel Load Ratio (VLR) or Vessel Discharge Ratio (VDR) differs by more than ± 0.30 % of the mean vessel/shore ratio.
a) The Inspector is responsible for calculating the VEF.
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