When composite materials are exposed to seawater it undergoes various processes of degradation such as matrix cracking, fiber breakage, delamination and interfacial debonding, resulting in the reduction in load carrying capacity. To improve the strength characteristics, Kevlar fibers are used in Marine applications. But Kevlar is prone to lot of moisture absorption and its adhesiveness towards the resin is also very much less. When exposed to seawater, the most noticeable effect is the plasticization of the matrix. This research attempts to investigate the reduction in flexural strength of ASTM D790 Kevlar/polyester specimens by 3 point bending test with AE monitoring using an INSTRON 3367 UTM, which are conditioned in seawater at non-laboratory conditions following ASTM-D5229 standard over different time intervals. The change in magnitude of AE parameters are correlated with the mechanical strength of Kevlar/polyester samples. Since Kevlar offers little resistance to Delamination, the focus of the study is being restricted to the failure modes such as debonding and Delamination.The range of Peak frequencies for various hydrolytically aged states for Kevlar samples are investigated using FFT analysis. Hits chosen randomly from each range of peak frequencies pertaining to each failure mode for various hydrolytically aged specimens are investigated using STFFT analysis.