The research examines the impact of nonlinear energy sinks (NES) on the reduction in the nonlinear vibratory responses of eccentrically stiffened functionally graded (ESFG) panels exposed to hydrodynamic loads. To simulate real marine environments, hydrodynamic forces, such as lift and drag that change with velocity, have already been determined experimentally using Matveev’s equations for a particular ship. The material composition of both the panel and the stiffeners varies across their thickness. The stiffeners are modeled using Lekhnitskii’s smeared stiffener approach. Additionally, analytical approaches implement the classical shell theory (CST) with considerations for geometric nonlinearity, along with the Galerkin method for calculations. The P-T method is subsequently employed to determine the nonlinear vibratory behavior of ESFG panels. In this method, the piecewise constant argument is used jointly with the Taylor series expansion, which is why it is named the P-T method. The findings reveal that NES can effectively dissipate vibrational energy, contributing to the extended service life of marine structures while reducing the need for frequent maintenance. This study supports sustainability objectives by increasing energy efficiency, lessening structural fatigue, and improving the overall environmental impact of marine vessels and infrastructure.