Outturn report and cargo shortage: measuring the gap

An outturn report records how much cargo actually came out of the ship, usually per receiving medium: shore tank, tank barge, road truck or coaster. It adds those figures up and sets the total against the bill of lading (B/L) weight. The difference is stated in tonnes and as a percentage of the B/L, and a shortage beyond the agreed threshold is the point to protest in writing.

What goes into an outturn report

Each receiving medium gets its own line, with the quantity and the method that produced it. For oils and fats, FOSFA's Code of Practice for Member Superintendents (revised November 2022) describes those methods. Shore tanks are dipped (the depth of liquid measured from the tank bottom) with a steel tape at the calibrated dip point, once the contents are stable, with free water and temperature measured. Ship's tanks are ullaged (the empty space measured from a fixed reference point down to the surface), noting draught, list and trim. Road and rail tanks are weighed gross and tare, or gauged on level ground. For barges, the code asks for the calibration details to be reported.

The code's discharge checklist adds two things that belong in the same file. On shore, tank figures are taken as provisional and final, and the receipt is calculated. On board, the ship's tanks are inspected empty and the residues estimated. For a discharge with damage or an abnormally high shortage, the code singles out the ullages and temperatures before discharge, the draught, list and trim, the weight on board, the seals, the discharge method and any sweepings recovered.

For dry bulk the outturn often comes from a joint draft survey or a shore weighbridge. Under the GAFTA Weighing Rules No.123, a draft survey is not a contractual weight unless both parties have accepted it in writing, and the method has to be stated on the weight certificate. Britannia P&I (2025) notes that receivers may reject a joint draft survey and argue for the terminal's own measurement. Which figure counts is a contract question; see the weight certificate and what a draft survey is.

How the outturn difference is calculated

The arithmetic is short:

• Total outturn = the sum of the figures per medium.
• Difference (MT) = total outturn − B/L weight. A negative figure is a shortage.
• Difference (%) = difference ÷ B/L weight × 100.

We keep three decimals for tonnes and for the percentage, rounding half up, and compare the unrounded figure with the threshold. That matters close to the line: a shortage of 60.480 MT on 12,000.000 MT is −0.504%, which shows as −0.50% at two decimals but is still more than 0.5%. Comparing in tonnes avoids the problem: 0.5% of 12,000.000 MT is 60.000 MT.

Worked example: just over and just under 0.5%

A fictitious parcel of crude sunflower oil, B/L weight 12,000.000 MT, is discharged in Rotterdam into a shore tank, two tank barges, a tanker and four road trucks. The shore tank gets a provisional figure at the end of discharge and a final figure later.

Receiving medium	Method	Provisional (MT)	Final (MT)
Shore tank 41	dip, temperature, density	6,482.316	6,484.116
Tank barge 1	sounding, barge calibration	2,148.905	2,148.905
Tank barge 2	sounding, barge calibration	1,817.442	1,817.442
Tanker	ullage	1,383.127	1,383.127
Road trucks (4)	weighbridge, gross and tare	107.510	107.510
Total outturn		11,939.300	11,941.100
Difference with B/L		−60.700	−58.900
Difference as % of B/L		−0.506%	−0.491%

The four truck tickets are 27.480, 26.915, 27.305 and 25.810 MT. On the provisional figures the shortage is 60.700 MT, 0.700 MT over the 60.000 MT that 0.5% represents: with a 0.5% threshold, that is a protest. The final dip adds 1.800 MT and the shortage drops to 58.900 MT, 1.100 MT under the line. The figures are fictitious.

A difference of 1.800 MT in one tank, 0.015% of the parcel, decides which side of 0.5% you are on. And the ship may well have sailed before the final dip. A protest issued on provisional figures should say so and reserve the right to amend; the American Club's guidance (2022) has the master reserve the right to extend a protest later, and a receiver's protest can do the same. How to write one is covered in the letter of protest and the note of protest.

Why outturn and B/L figures differ

The American Club (2022) lists the usual grounds for a difference between the B/L quantity and the quantity discharged. Grouped, with points from Britannia and FOSFA added:

• Measurement. Draft readings, ballast and bilge calculations, the ship's constant, tallies, and shore scales that are manipulated or not calibrated. Britannia puts weighbridge accuracy at typically 0.5% to 1.0%, depending on the port. FOSFA's code warns that a ship's tank calibration is generally based on the builders' drawings, so its accuracy may be limited.
• Temperature and density. In a liquid cargo, weight is calculated from volume, temperature and density; the American Club names incorrect temperature or density calculations as a separate cause.
• Water. Water loaded with the cargo and discharged or evaporated in transit. For oils, FOSFA notes that free water is often hard to measure accurately in a tank.
• Cargo remaining on board. Residues in the ship's tanks or holds are not outturn. Britannia recommends an empty hold certificate for dry bulk; for oils, the residue estimate after discharge is part of the file.
• Real loss. Spillage, mishandling, theft or pilferage during discharge. With several discharge ports, Britannia reports cases where a "loss" at one port was likely cargo over-discharged at the previous one.

The idea behind a threshold

Two measurements taken at different ports, often by different methods, will not agree exactly, and part of any gap is noise. A threshold separates that noise from a difference worth protesting. The American Club puts the trade allowance for bulk and liquid cargoes at generally 0.5% to 1% of the B/L quantity, unless the charter party provides otherwise. The Hague-Visby Rules, for their part, list "wastage in bulk or weight" among the causes of loss for which the carrier is not responsible (Art. IV r. 2(m)).

A threshold is a trigger, not a settlement. Under the sale contract the outturn can have consequences of its own: FOSFA contracts No. 54 and No. 80 are delivered-weight contracts with an Adjustment of Outturn Clause, and FOSFA publishes settlement prices where that clause applies (fosfa.org, September 2026). Against the carrier, the American Club describes shortage claims as arising from discrepancies outside the accepted range, and those need evidence. See cargo claims in bulk shipping.

Based on the working practice of our sector specialist: 25 years in the port, 20 of them as a cargo surveyor. A protest is usually raised from 0.5% for vegetable oils; 0.3% is the standard in chemicals, and some clients work with 0.3%.

Outturn per medium, flagged automatically

FOSS is software for inspection companies and the port, with a sector specialist at the table. Measurements are entered once, offline on board if need be, and the outturn per medium is set against the B/L weight with an automatic protest flag at more than 0.5% short. The flag is a prompt; the surveyor decides whether and when to protest. To see it on your own discharge figures, get in touch.