Internal turret system is one of the most popular single point mooring systems that is uniquely integrated with the FPSO hull and connects with both mooring lines and risers/umbilicals. Hydrodynamic aspects of various single point mooring systems have been intensively researched and studied. However, industry standards of deriving the various load components and their correct combination for the purpose of turret structure design are not well documented. This paper presents the procedures of deriving the turret design loads for the structure design of an internal turret using a roller upper bearing system. Based on a sample case of a deepwater FPSO operating in a harsh environment, detailed descriptions of the various load components and their impacts on structural design and mechanical system selection are examined. A summary of the design cases and loads combinations are presented. In addition, various design parameters and their criticalities are studied. The paper concludes that the correct prediction of turret design loads is an important step towards the safe design of Deepwater FPSOs.

This content is only available via PDF.
You can access this article if you purchase or spend a download.