Comparison Study on Bottom Plate Effect on Single Hydrocarbon Storage Tank Through Decay Test

Abstract

A novel Floating Hydrocarbon Storage and Bunker Facility (FHSBF) is designed for use of nearshore area around Singapore. The system will be composed of floating hydrocarbon storage tanks (FHST) and supporting barges. The FHST will be freely floating vertically while restrained horizontally by fenders installed on the barges. Two concepts for the FHST are designed different bottom shapes, namely with and without bottom skirt. The function of bottom skirt is to serve as a heave plate and it is expected to influence the hydrodynamic properties including hydrodynamic damping and natural periods of a single tank. To investigate the bottom shape effect on hydrodynamic responses of single FHST, model tests were carried out in the wave basin at National University of Singapore for various wave conditions. Two tank models together with the model test setup are introduced and the decay test results of surge, pitch, heave and yaw motions for two different tanks are compared. Results show that with bottom skirt, heave natural period is significantly increased, and the skirt will introduce additional viscous damping that helps reduce both heave, pitch and surge motions.