Member states in the Paris and Tokyo memoranda of understanding (MOUs) on port state control are launching a new campaign on ship stability.

Inspectors will carry out 10,000 checks on vessels from 1 September, the organisations said.

They will question crew members to find out if they are familiar with assessing stability on completion of cargo operations before the ship leaves port, and during all stages of the voyage.

The port-state-control bodies also want to create awareness among seafarers and shipowners of the importance of calculating the stability condition.

Inspectors will be checking that vessels comply with intact stability requirements under International Maritime Organization regulations.

The campaign will last for three months, but vessels will only be inspected once during that time.

Check-list ready

A questionnaire will be used to check that equipment is properly maintained and functioning.

If deficiencies are found, the organisations said masters will be asked to rectify them within a certain period of time.

Vessels risk detention until faults are fixed, owners were warned.

The results of the campaign will be analysed and findings will be presented to the governing bodies of both MoUs for submission to the IMO.

The first question will be whether the ship has been provided with approved stability information, which can be understood and easily used by the master and loading officer.

Further checks relate to the use of this data before departure, evidence that the crew can assess stability and whether the calculated displacement and trim corresponds with observed draughts.

Containerships in particular have been the focus of safety efforts in recent years.

The average number of boxes lost overboard rose to a seven-year high of more than 3,000 in 2020, and this year may outpace that.

In June, Weathernews marine group operations general manager Amy Buhl wrote in TradeWinds that "stiff and tender" ships are more susceptible to vessel motions, particularly resonant motions such as synchronous or parametric rolling, successive wave attack or loss of intact stability.

She added that larger roll angles increase stresses on twist locks on the highest tiers of containers.

Buhl warned that as ships grow larger, their handling in heavy weather is not as well understood, and masters may have less experience with the countermeasures needed to avoid or minimise problematic vessel motions.