Reducing roll motion by passive free surface tanks

• Published in: Volume 7: Ocean Space Utilization; Professor Emeritus J. Randolph Paulling Honoring Symposium on Ocean Technology
• Main Authors: Nielsen, Ulrik Dam, Nielsen, Christian S.
• Format: Other Non-Article Part of Journal/Newspaper
• Language: English
• Published: American Society of Mechanical Engineers 2014
• Subjects: Arctic
• Online Access: https://orbit.dtu.dk/en/publications/fae6e773-4572-4f1f-9e3c-364155fe2b81; https://doi.org/10.1115/omae2014-23299

Roll stabilisation of motorised vessels plays an important part in reducing passenger discomfort and increasing safety and cargo capacity. Passive free surface tanks are considered a low-cost stabilising method, which is efficient at all speeds without increasing hull resistance. In this study, a mathematical model for evaluating the performance of a passive free surface tank is established. This is done by coupling a roll model to a fluid flow model. As a numerical example, the seakeeping abilities of a container vessel are evaluated. The necessary methods for performing the simulation are presented and the design of a free surface tank is explained. The effects of the passive free surface tank are evaluated and a significant damping effect is observed, particularly in cases with resonant roll.