In 2005 the Joint Industry Project 'Offloading Operability') will be completed. Within this project, a tool is developed for the simulation of complex tandem offloading operations, including the approach manoeuvres. Besides development of this tool, research was executed into the interaction effects when two vessels are in close proximity. A method was developed to compute wind and current interaction. Wind tunnel tests were executed to gather data regarding wind and current loads on vessels, both shielded and unshielded. Finally and extensive set of model tests was executed to gather a representative data set for various tandem offloading solutions and for the validation of the SHUTTLE tool.