Container weight requirements
Shippers must provide the verified gross mass (VGM) of each container on the shipping documents. The ship’s master cannot allow a container to be loaded without this information.
Weighing methods
You can determine VGM by either of these methods:
- Method one – weigh the packed container using calibrated and certified weighing equipment.
- Method two – weigh all the individual contents of the container, including any packing material and dunnage, and add this to the tare weight of the empty container.
Why verified weights are needed
The VGM requirement is intended to protect the safety of ships and seafarers.
SOLAS has always required shippers to declare the weight of their cargo. However, serious shipping incidents have shown that declared container weights are often inaccurate or significantly understated.
Incorrectly declared container weights make it difficult to plan cargo stowage safely. This can result in:
- container stacks collapsing
- excessive stress on the ship’s structure
- instability of the ship.
Shippers’ obligations
The obligation to provide VGM is on the shipper, that is, the person who offers the goods for carriage by sea.
Who the shipper is in a particular case depends on the commercial contract for shipping the goods that the exporter enters into.
For method two, where an organisation consolidates and packs items from several shippers into one container, the consolidator may require declared weight information for individual consignments from each shipper.
VGM information may be provided in electronic format.
The shipping document that states the VGM must be signed by a person authorised by the shipper. Where another party, such as a freight forwarder or road‑transport operator, submits pre‑advice notices (including VGM) to ports and shipping lines on the shipper’s behalf, the shipper must have a process for authorising those parties.
Weighing equipment
For method one, calibrated and certified equipment means trade‑approved weighing instruments. These are instruments approved in accordance with the Weights and Measures Act and Regulations.
Trade‑approved equipment used to determine VGM must:
- comply with legal tolerances
- have a current certificate of accuracy.
Weighing instruments approved as Class III or IIII must have a scale interval of no more than 50kg. Scale intervals for other instrument classes will be considered on a case‑by‑case basis.
The Ministry of Business, Innovation and Employment (MBIE) Trading Standards Group:
- approves and certifies weighing equipment in New Zealand, including weighbridges
- maintains a database of approved weighing equipment.
Method two gives shippers some flexibility in how they calculate VGM. For example, they may use:
- predetermined weights of standard items
- established volume‑to‑weight conversions.
These procedures should:
- be based on methods of known accuracy
- be supported by appropriate quality‑control systems, such as an enterprise resource planning (ERP) system or similar
- ensure a consistent process and verifiable weights
- provide an accurate and reliable VGM comparable to method one.
Maritime NZ will not provide formal approval of shippers’ procedures for method two. Maritime NZ may provide guidance on types of processes that would be considered acceptable.
Not all cargoes are suitable for method two. In some cases, weighing the packed container will be the only practicable option.
Contact your freight company and shipping line
Ports and shipping lines have their own rules for receiving VGM information for export containers, including:
- accepted formats for electronic transmission
- cut‑off times for supplying VGM information.
These are commercial matters between shippers and other parties in the transport chain.
In the first instance, shippers should contact:
- their freight companies
- carriers
- packers and consolidators
- freight forwarders
- shipping lines
to find out what each requires.