A PREDICTION OF STRUCTURAL LOAD AND RESPONSE OF A SWATH SHIP IN WAVES

ABSTRACT The small‐waterplane‐area‐twin‐hull (SWATH) ship has long been recognized as a promising high performance ship because of its superior seakeeping characteristics as compared to the conventional monohull or the catamaran ship. Over the years, many advancements in prediction methods for motions and wave loads of the SWATH ship have been published. Using this knowledge, a computational procedure for predicting structural load and response of the SWATH ship was developed and is presented here. The analytical method for wave load determination is based on a linear seakeeping theory where hydrodynamic interaction between the twin hulls has been included. The structural response of a SWATH ship can be calculated by using finite element models and hydrodynamic pressure distributions along the ship hulls. A correlation study has shown good agreement between calculated results and model test data of a 3,000‐ton SWATH ship in motions and loads, indicating that the analytical approaches could be used in assessing the seaworthiness and structural adequacy of SWATH designs. To demonstrate the computational procedure, a case study of a T‐AGOS 19 SWATH ship in sea state 7 was carried out. The calculated results of motions, loads, deflections, and stresses are presented and discussed. However, the fatigue life of the vessel has not been investigated in this paper.