Key points
- State whether loading weight or discharge weight governs.
- Weighing method and tolerance belong in the contract.
- Moisture change in transit legitimately alters delivered weight.
Methods
Weighbridge weighing, calibrated flow scales, and draft survey for bulk vessels. Each has a different accuracy range, and the contract should name the accepted method rather than leaving it to whatever the terminal provides.
Loading versus discharge weight
Weight normally changes in transit through moisture loss or gain and handling losses. Which weight governs payment is a commercial allocation of that variation and must be explicit in the contract.
Tolerances and franchise
Contracts commonly allow a tolerance before a weight difference becomes claimable. Without it, minor and unavoidable measurement variation becomes a dispute on every shipment.
What to verify
- Governing weight point stated in the contract
- Weighing method and calibration evidence documented
- Tolerance and claim procedure defined
Risks to manage
- Paying loading weight on cargo that lost weight in transit
- Uncalibrated equipment producing unreliable certificates
- Weight shortfall disputed with no agreed tolerance
Common mistakes
- Leaving the governing weight point unstated
- Ignoring moisture change when comparing weights
- Accepting a certificate with no method or calibration reference
Frequently asked questions
Why do loading and discharge weights differ?
Moisture exchange with the atmosphere, handling losses, dust and measurement tolerance. Differences within a normal range are expected rather than evidence of shortage.
Is draft survey accurate enough?
It is standard for bulk vessels and accepted commercially, but its accuracy range is wider than weighbridge weighing, which is why tolerances exist.
Related reading
Technical references
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