The present investigation examines the geometric optimisation of a submerged wave energy converter situated near a partially reflecting sloped seawall for the Indian sea-state. This is achieved by utilising the Response Surface Methodology (RSM) in conjunction with Design of Experiments (DOE). The study aims to model various shape configurations, specifically circular, elliptical, rectangular, and square cross-sections of submerged wave energy converters (S-WECs), and conduct a parametric analysis. Frequency domain analysis using the Boundary Element Method (BEM) reveals that the submerged rectangular wave energy converter (SR-WEC) outperforms all considered geometries in total capture width ratio ( \(C_\textrm{P}\) ), surpassing the circular, square, and elliptical configurations by approximately \(33\%\) , \(15.8\%\) , and \(4.5\%\) , respectively. Moreover, the study aims to elucidate the influence of the reflection wall coefficient of the sloped seawall, submergence depth, oblique wave attack, and relative distance from the sloped seawall on the energy capture efficiency of the SR-WEC. The findings show that the performance of an SR-WEC placed in the vicinity of a fully reflecting sloped seawall is approximately \(73\%\) higher than in open sea conditions. The quadratic polynomial derived from the RSM predicted model of maximum WEC power \((P_\textrm{WEC})_\textrm{max}\) , along with the total \(C_\textrm{P}\) , constitutes a two-objective problem. The optimised buoy configuration is used to estimate the annual power extraction potential of the WEC at Chavara, Kerala, India (latitude \(9.00^\circ\) N, longitude \(76.420^\circ\) E), yielding an estimated annual energy production (AEP) of \(26.9~\text {MWh m}^{-1}\text { year}^{-1}\) . The study underscores the effectiveness of combining BEM with RSM to customise WEC for specific regional wave conditions, thereby enhancing cost-effective wave energy extraction.
