A ship-to-ship (STS) transfer operation is the transfer of cargo between seagoing ships positioned alongside each other, either while stationary or underway. Cargoes typically transferred via STS methods include crude oil, liquefied gas (LPG or LNG), bulk cargo, and petroleum products.
Ship-to-ship transfer operations take place at open sea or at OPL. The involved parties are the 2 participating vessels and the Service Provider who provides the STS equipment and the qualified Mooring Master (Person in Overall Advisory Control, POAC). There is no direct contractual relationship among those parties and both Masters are responsible for ensuring safety. Thus prudent exercise of due diligence prior commencement of the STS Operation is the only way that will allow the Masters in ensuring safety. Due diligence should take place in the following phases of the Ship-to-Ship operation:
- Ship nomination and clearance requests
- Appointment of Service Provider and POAC
- Technical advice to the Master by his technical Operator
- Risk Assessment procedure
STS Operations are part of vessel's operation. Until 2009 there were no international regulations that explicitly prescribe how these operations should take place. These operations are carried out in accordance with guidelines set out by the latest Oil Companies Internacional Marine Forum and the International Chambers of Shipping (ICS), with the strictest adherence to safety regulations. These are the industry guidelines which are part of the contractual commitment between the ship owner and the STS Organizer (Charterer, Cargo owner, Oil Major etc.)
According to International Maritime Organization regulations vessels transferring OIL CARGO must have an approved STS operational manual that describes the procedure. These manuals should be available on board not later than first annual, intermediate or special survey after 1 January 2011. These manuals can be prepared either by the shipping company or external consultants.
According to IMO MEPC 186(59) records of STS Operations should be retained for 3 years. Although the records consist on STS checklists and Risk Assessment procedure those should be assessed after the completion of the STS Operation and the outcome of the assessment should be utilized in the Due diligence process. When Masters plan an STS Operation they should have easy access to the past STS records and assessments in order to prepare the ship and crew towards ensuring safety according to industry guidelines and IMO regulation. Technical Operators are subject to assessment by oil major companies that proper implementation of the record assessment take place.