Ship-to-stock (STS) systems are used to streamline the transfer of goods between ships. Let’s break down the key phases:

Candidacy: This stage includes all the preparations required before approaching the port of operation. It involves obtaining permission from local authorities, creating a Joint Plan of Operation based on risk assessment, considering environmental conditions, available water space, communication, crew training, vessel size, and cargo risk factors. Ballasting/deballasting operations are also completed during this stage.

Qualification: During the approach and mooring stage, detailed calculations are conducted considering environmental conditions, vessel size, and arrangements. Controlled speed and effective use of available means (such as tug boats, line boats, and fenders) are essential for safe berthing. An officer experienced in STS operations should be appointed to control the conduct of the operation.

Maintenance: Once the berthing phase begins, the “Guide” vessel (usually the larger ship) steers the “Lightering Course” at steady revs to maintain the “lightering speed.” Yokohama fenders are used, and STS procedures must be thoroughly understood aboard both ships by the Master.

In summary, the STS system involves careful planning, safe berthing, and effective control to ensure successful cargo transfer between ships.