AN INCORRECT input of container weights led to the loss of 23 containers on board a US-flagged containership, a National Transportation Safety Board report has found.

The 2005-built, then US-flagged (now Malta), 7,421 teu President Eisenhower (now CMA CGM Shanghai (IMO: 9295220)) was operated by CMA CGM subsidiary American President Lines.

It lost 23 containers overboard while waiting for a berth at Oakland on February 6, 2024, after leaving Los Angeles on February 3.

An NTSB report has found that the weights of 39 containers were incorrectly entered by a booking agent, and as a result the verified gross mass of those containers was also incorrect.

A booking of 40 containers was automatically flagged because one container was overweight. To overcome the issue, the agent split the reservation into two separate bookings of 39 boxes and one, but an error with the system meant the weights for each of the 39 boxes had to be entered manually.

These weights were recorded as 2,500 kg, which when added to the tare weight of the containers gave VGMs between 6.2 tonnes and 6.4 tonnes. According to the bill of lading, the actual VGMs were between 24.5 tonnes and 28.6 tonnes.

But it was the incorrect VGMs which informed the cargo loading plan drawn up by the ship planner team.

As a result, heavier containers were inadvertently loaded higher up some stacks than lighter containers at Los Angeles, meaning the centre of gravity for those stacks was much nearer the top. This arrangement is known as reverse stratification.

The operator said the vessel would not have departed with that configuration, had it been known.

Lashing equipment is subjected to much higher forces in reverse stratification, and as the vessel awaited a berth off Oakland on February 6, wind and sea conditions increased and the vessel began to roll.

At 2135 hrs, an able seaman noticed what looked like smoke on the port side of the vessel. That smoke turned out to be powder in the air from collapsed containers.

In total, some 23 containers fell overboard and an additional 10 boxes were damaged. The total value of the lost cargo was estimated to exceed $630,000.

The report found that because the cargo loading plan was created using inaccurate data, it showed that the stack weights of bay 42 (where the containers were lost from) were within the maximum stack weight prescribed by the vessel’s cargo securing manual.

The VGMs were not verified at the terminal, the report found, and the terminal cranes did not have the capability to weight the containers.

This is the latest chapter in an ongoing saga involving container weights. Amendments to the Safety of Life at Sea Convention came into force in 2016 which required all containers to have a VGM before being stowed on a vessel.

But like any International Maritime Organization regulation, enforcement is up to member states, and what followed was a lengthy saga on whether the US Coast Guard would in fact enforce the new rules or not.

The President Eisenhower incident is another reminder of how a few incorrect weights can add up quickly into a much bigger problem on board a multi-thousand teu vessel.