Abstract One of the concerns about using a heave plate on a SPAR floater is that the pitch response will be inadequately minimized. This weakness will result in excessive misalignment conditions in the floater wind. The vortex ring state phenomenon is a more complex effect and the most common potential issue. This issue may result in over-performance of wind turbine system components. A time domain based experimental test was developed in this study to investigate the extent to which the number and configuration of vertical plates influence pitch response, which is useful for improving wind energy extraction performance. Because the vertical plate configuration is an important key parameter, the following arrangements are proposed to be investigated: solid plates, three-perforated plates, and six-perforated plates. 3VP-S, 3VP-3H, 3VP-6H, 4VP-S, 4VP-3H, 4VP-6H, 5VP-S, 5VP-3H, and 5VP-6H are the modified SPARs. The ballasting area is where the modified vertical plate of the base SPAR is located. In 120 regular wave cycles, the effects of the proposed model's pitch response, pitch reduction percentage, wave steepness, natural period, and viscous damping were evaluated. The wave tank was used to test ten different scenarios. The 4VP-6H, 5VP-3H, and 4VP-S models were identified to provide better estimates than other modified models. The perforated plate is confirmed to be more effective at reducing pitch motion than the solid plate and base SPAR. The increase in pitch response is consistent with the increase in applied wave parameters. The model was also initiated to be in dominant stand-by mode for all wave parameters. Because of the reduced volume caused by the SPAR body modification, the percentage reduction in pitch motion increases with decreasing wave loads. When compared to the base SPAR, the proposed model's pitch reduction percentage ranges from 19 to 56%. In all scenarios, the wave steepness relationship is inversely proportional to the pitch reduction percentage. Furthermore, none of the proposed models are closer to the natural frequency than the base SPAR, resulting in the lowest resonance. The perforated plate also dampens more effectively than the base SPAR. This is primarily due to the geometry of the vertical plate and its configuration layout. Finally, as the most recent conceptual design in wind floater SPAR, the 4VP-6H model is deeply recommended.KeywordsPitch responsesSPAR floater windVertical platesWave parameters