The Draft Survey Said 54,800 MT. The BL Said 55,000 MT.
Quote from chief_editor on April 17, 2026, 11:08 amWeight discrepancies between draft surveys and bills of lading in bulk commodity trade create disputes over shortage claims and financial exposure.
The bill of lading stated 55,000 MT of iron ore fines loaded at Saldanha Bay. The draft survey at loading — conducted by measuring the vessel's displacement before and after loading — indicated 54,800 MT. The shore scale — the conveyor belt weighing system at the terminal — recorded 55,050 MT. The BL was issued based on the shore scale figure, rounded to 55,000 MT. At the discharge port in Qingdao, the draft survey indicated 54,650 MT. The difference between the BL figure and the discharge draft survey was 350 MT. At $110 per MT, the apparent shortage was worth $38,500.
The buyer filed a shortage claim. The seller argued that the loading draft survey already showed a discrepancy with the shore scale, suggesting the shore scale was the more accurate measurement. The buyer argued that the BL figure was the contractual quantity and the discharge draft survey confirmed a shortage. The dispute centered on which measurement was authoritative — and in physical commodity trade, that question is less straightforward than it appears.
Draft Surveys Are Estimates, Not Measurements
A draft survey determines the weight of cargo by calculating the difference in the vessel's displacement (weight of water displaced) before and after loading or discharge. The calculation uses the vessel's hydrostatic tables, adjusted for ballast, fuel, freshwater, and other variables. The accuracy of a draft survey depends on the vessel's trim and list, the density of the water (which varies with salinity and temperature), the accuracy of the tank soundings, the condition of the vessel's hydrostatic data, and the sea conditions at the time of the survey.
Industry consensus is that a draft survey conducted under favorable conditions — calm water, minimal trim, accurate tank soundings — has an accuracy of approximately ±0.5% of the cargo weight. On a 55,000 MT cargo, that is ±275 MT. The 200 MT discrepancy between the loading draft survey (54,800 MT) and the BL figure (55,000 MT based on shore scale) falls within the expected accuracy tolerance of the draft survey. It does not necessarily indicate that 200 MT less cargo was loaded. It may indicate that the draft survey measurement was 200 MT lower than the shore scale measurement — which is within the normal range of variation between these two methods.
At the discharge port, the draft survey indicated 54,650 MT — 150 MT less than the loading draft survey. This could represent actual cargo loss during transit (spillage, dust emission during loading, moisture evaporation), or it could represent measurement variation between two draft surveys at two different ports with different water conditions. A 0.27% difference between two draft surveys on a 55,000 MT cargo is well within the expected measurement tolerance.
The problem is that contracts and LCs reference the BL weight as the basis for payment and claims. The BL states 55,000 MT. The discharge survey states 54,650 MT. The 350 MT difference is the shortage claim. The fact that this difference may be entirely attributable to measurement methodology rather than actual cargo loss does not eliminate the commercial claim — it makes the claim harder to assess, not easier.
The Contract Should Specify Which Weight Governs and What Tolerance Applies
The operational solution to weight discrepancy disputes is contractual precision. The contract should specify: which weighing method is used at loading (shore scale, draft survey, or weigh-bridge), which weighing method is used at discharge, which measurement is final for commercial settlement, and what tolerance is allowed before a shortage claim can be filed.
If the contract specifies that the loading shore scale weight is final, the seller is protected against discharge draft survey variations. If the contract specifies that the discharge draft survey is final, the buyer is protected but the seller is exposed to measurement uncertainty. A common middle ground is to specify that the average of loading and discharge weights applies, or that shortage claims are valid only if the discrepancy exceeds 0.5% of the BL weight.
A 0.5% threshold on a 55,000 MT cargo means that shortages below 275 MT are within the contractual tolerance and do not trigger a claim. The 350 MT shortage in the iron ore example exceeds this threshold and would therefore be a valid claim — but only by 75 MT above the tolerance, reducing the claim value from $38,500 to approximately $8,250.
Traders who handle large volumes of bulk cargo on a regular basis — 20 or more Panamax or Capesize shipments per year — report that weight discrepancies between load and discharge fall within 0.5% on approximately 70 to 80% of shipments. Discrepancies between 0.5% and 1.0% occur on roughly 15 to 20% of shipments. Discrepancies above 1.0% — which represent potential actual shortage rather than measurement variation — occur on fewer than 5% of shipments.
The $38,500 claim on the Saldanha Bay iron ore shipment was eventually settled by splitting the difference — the seller paid approximately $19,000. The arbitration was avoided. Both parties absorbed legal costs of approximately $5,000 each. The total transaction cost of the weight dispute was roughly $29,000 — on a trade margin of approximately $160,000. The dispute consumed 18% of the margin and was resolved on the basis of compromise rather than precision, because the underlying measurements did not support precision. Two draft surveys and a shore scale produced three different numbers. None of them was wrong. None of them was definitive. The contract did not specify which one governed, so the parties split a difference that neither could accurately define. The traders who write weight determination clauses with the same care they write price clauses do not have this problem. The traders who use template contracts without customizing the weight and measurement provisions have it repeatedly.
Keywords: draft survey BL weight discrepancy bulk commodity shortage | draft survey accuracy commodity trade, bulk cargo weight shortage dispute, bill of lading weight discrepancy, cargo shortage claim physical trade
Words: 956 | Source: Industry pattern — documented across multiple sources | Created: 2026-04-08
Weight discrepancies between draft surveys and bills of lading in bulk commodity trade create disputes over shortage claims and financial exposure.
The bill of lading stated 55,000 MT of iron ore fines loaded at Saldanha Bay. The draft survey at loading — conducted by measuring the vessel's displacement before and after loading — indicated 54,800 MT. The shore scale — the conveyor belt weighing system at the terminal — recorded 55,050 MT. The BL was issued based on the shore scale figure, rounded to 55,000 MT. At the discharge port in Qingdao, the draft survey indicated 54,650 MT. The difference between the BL figure and the discharge draft survey was 350 MT. At $110 per MT, the apparent shortage was worth $38,500.
The buyer filed a shortage claim. The seller argued that the loading draft survey already showed a discrepancy with the shore scale, suggesting the shore scale was the more accurate measurement. The buyer argued that the BL figure was the contractual quantity and the discharge draft survey confirmed a shortage. The dispute centered on which measurement was authoritative — and in physical commodity trade, that question is less straightforward than it appears.
Draft Surveys Are Estimates, Not Measurements
A draft survey determines the weight of cargo by calculating the difference in the vessel's displacement (weight of water displaced) before and after loading or discharge. The calculation uses the vessel's hydrostatic tables, adjusted for ballast, fuel, freshwater, and other variables. The accuracy of a draft survey depends on the vessel's trim and list, the density of the water (which varies with salinity and temperature), the accuracy of the tank soundings, the condition of the vessel's hydrostatic data, and the sea conditions at the time of the survey.
Industry consensus is that a draft survey conducted under favorable conditions — calm water, minimal trim, accurate tank soundings — has an accuracy of approximately ±0.5% of the cargo weight. On a 55,000 MT cargo, that is ±275 MT. The 200 MT discrepancy between the loading draft survey (54,800 MT) and the BL figure (55,000 MT based on shore scale) falls within the expected accuracy tolerance of the draft survey. It does not necessarily indicate that 200 MT less cargo was loaded. It may indicate that the draft survey measurement was 200 MT lower than the shore scale measurement — which is within the normal range of variation between these two methods.
At the discharge port, the draft survey indicated 54,650 MT — 150 MT less than the loading draft survey. This could represent actual cargo loss during transit (spillage, dust emission during loading, moisture evaporation), or it could represent measurement variation between two draft surveys at two different ports with different water conditions. A 0.27% difference between two draft surveys on a 55,000 MT cargo is well within the expected measurement tolerance.
The problem is that contracts and LCs reference the BL weight as the basis for payment and claims. The BL states 55,000 MT. The discharge survey states 54,650 MT. The 350 MT difference is the shortage claim. The fact that this difference may be entirely attributable to measurement methodology rather than actual cargo loss does not eliminate the commercial claim — it makes the claim harder to assess, not easier.
The Contract Should Specify Which Weight Governs and What Tolerance Applies
The operational solution to weight discrepancy disputes is contractual precision. The contract should specify: which weighing method is used at loading (shore scale, draft survey, or weigh-bridge), which weighing method is used at discharge, which measurement is final for commercial settlement, and what tolerance is allowed before a shortage claim can be filed.
If the contract specifies that the loading shore scale weight is final, the seller is protected against discharge draft survey variations. If the contract specifies that the discharge draft survey is final, the buyer is protected but the seller is exposed to measurement uncertainty. A common middle ground is to specify that the average of loading and discharge weights applies, or that shortage claims are valid only if the discrepancy exceeds 0.5% of the BL weight.
A 0.5% threshold on a 55,000 MT cargo means that shortages below 275 MT are within the contractual tolerance and do not trigger a claim. The 350 MT shortage in the iron ore example exceeds this threshold and would therefore be a valid claim — but only by 75 MT above the tolerance, reducing the claim value from $38,500 to approximately $8,250.
Traders who handle large volumes of bulk cargo on a regular basis — 20 or more Panamax or Capesize shipments per year — report that weight discrepancies between load and discharge fall within 0.5% on approximately 70 to 80% of shipments. Discrepancies between 0.5% and 1.0% occur on roughly 15 to 20% of shipments. Discrepancies above 1.0% — which represent potential actual shortage rather than measurement variation — occur on fewer than 5% of shipments.
The $38,500 claim on the Saldanha Bay iron ore shipment was eventually settled by splitting the difference — the seller paid approximately $19,000. The arbitration was avoided. Both parties absorbed legal costs of approximately $5,000 each. The total transaction cost of the weight dispute was roughly $29,000 — on a trade margin of approximately $160,000. The dispute consumed 18% of the margin and was resolved on the basis of compromise rather than precision, because the underlying measurements did not support precision. Two draft surveys and a shore scale produced three different numbers. None of them was wrong. None of them was definitive. The contract did not specify which one governed, so the parties split a difference that neither could accurately define. The traders who write weight determination clauses with the same care they write price clauses do not have this problem. The traders who use template contracts without customizing the weight and measurement provisions have it repeatedly.
Keywords: draft survey BL weight discrepancy bulk commodity shortage | draft survey accuracy commodity trade, bulk cargo weight shortage dispute, bill of lading weight discrepancy, cargo shortage claim physical trade
Words: 956 | Source: Industry pattern — documented across multiple sources | Created: 2026-04-08