What Is VGM (Verified Gross Mass)? The SOLAS Rule Explained

For many years container weights were simply declared, and declared figures could differ substantially from actual weights. Misdeclared weights directly affect the vessel's stability calculation, the stowage plan and the loads imposed on container stacks.

Overweight boxes crushing those below, stack collapses, containers lost overboard and overloaded port equipment all pointed to the need for an international verification rule. It should be understood as a safety measure rather than a paperwork formality.

Under SOLAS, the party responsible for obtaining and declaring the VGM is the shipper named on the bill of lading or equivalent transport document. The shipper may weigh the container itself or use a weighing service, but responsibility for the declaration stays with the shipper.

The VGM must reach the master or his representative and the terminal representative early enough to be used in preparing the ship's stowage plan. In practice this is tied to the VGM cut-off set by the line and the terminal.

The regulation provides two methods. Which one is used depends on the shipper's facilities and the cargo, and in both cases weighing equipment must be calibrated and meet national requirements.

Method 1 is usually practical for shippers who pack at their own premises and have access to a weighbridge. Method 2 may suit shipments of many identical packages whose individual weights are already known. Whichever method is used, keeping the weighing or calculation records makes it easier to show the basis of the declaration if questions arise later.

The declaration can be on paper or electronic, and lines and terminals usually accept submissions through their own systems. Formats differ but the core content is similar.

The most frequent error is leaving out the container tare under Method 2, or using the tare marked on the door without checking it. Forgetting dunnage, timber and chocks also opens a gap between declared and actual weight.

Other common problems include passing off estimates as verified figures, using scales whose calibration has lapsed and not updating the declaration after a last-minute change to the cargo. Even with a correct total, weight concentrated at one end of the box is a separate risk, which the CTU Code addresses under load distribution.

A packed container without a timely VGM should not be loaded. In practice it is held at the terminal and may roll to the next vessel, bringing storage charges, delays and missed delivery dates.

Some terminals offer to weigh containers on their own scales when a declaration is missing. How differences between declared and terminal weights are handled, and what tolerances apply, depend on the national administration's rules and terminal practice.

VGM is the shipper's responsibility and is not part of the normal scope of container loading supervision. Even so, checking container numbers against the loading list during supervision can help identify early any boxes that are on the list but held back on the quay for lack of a VGM.

Karan Gözetim provides container loading and discharge supervision from Gemlik; the scope is agreed at the quotation stage.