In the previous chapters, all the problems have been studied under the assumption of small amplitude water wave theory and small amplitude structural response. However, in the present chapter, gravity wave interactions with large flexible floating structures are analysed under the assumption of small amplitude shallow water approximation and structural response. The basic equations of wave structure interaction problems under shallow water approximation are briefly derived. Then, the solution procedures associated with the interaction of oblique wave scattering by floating elastic plates are discussed in several cases by matching the velocity and pressure at the interfaces. The utility of wide spacing approximation to deal with wave scattering by multiple floating structures is demonstrated in several cases. Although, the main emphasis in this chapter is on problems of single frequency, timedependent problems associated with the hydroelastic analysis of large floating structures under shallow water approximations are briefly reviewed. Further, various methods associated with the reduction of the structural response of large floating structures is briefly reviewed.