This paper presents an analysis on attenuation of floating structures response to underwater shock. An explicit finite element approach interfaced with the boundary element method is used for the shockfluid-structure interaction. The bulk cavitation induced by underwater shock near the free surface is considered in this study. Two types of floating structural configurations are modeled: one is the two-layered panel and the other is the sandwich panel, both of which are extracted from the typical floating hulls-the former corresponds the single hull with coating material and the latter corresponds to the double hull with different material fillings. Their effective structural damping and stiffness are formulated and incorporated in the fluid-structure-coupled equations, which relate the structure response to fluid impulsive loading and are solved using the coupled explicit finite-element and boundary element codes. The cavitation phenomenon near free surface is captured via the present computational procedure. The attenuation effects of the floating structure response to underwater explosion are examined. From the results obtained, some insights on the improvement of floating structures to enhance their resistance to underwater shock are deduced.