Peric, RobinsonRobinsonPericBerndt, JannesJannesBerndtAbdel-Maksoud, MoustafaMoustafaAbdel-Maksoud2026-04-232026-04-232026-03-26Journal of Hydrodynamics (in Press): (2026)https://hdl.handle.net/11420/62835Three different approaches to generate long-crested extreme waves near the onset of breaking are investigated: Stokes 5th-order wave theory, linear focusing based on the NewWave theory and nonlinear focusing via Peregrine-breather-type rogue waves. The aims of this work are to compare the extreme-wave dynamics and to investigate the influence of structure placement on the maximum horizontal forces. An efficient simulation approach based on the finite-volume method was proposed for these investigations. Fixed vertical cylinders with diameters of 5% to 20% of the wavelength were subjected to the waves. The present results show that extreme-wave dynamics varied considerably. Wave breaking started at ca. 60% (linear focusing) and ca. 72% (rogue wave) of theoretical maximum steepness for a regular wave. For same wave height and steepness, linear focusing or rogue wave had up to ca. 14% larger maximum crest height H<inf>c,max</inf> compared with the Stokes waves. For similar wave steepness, the Stokes wave gave the smallest horizontal forces, whereas whether linear focusing or rogue wave would give the largest forces depended on the severity of wave breaking. The main finding of this work is that the maximum horizontal force did not occur when the structure was positioned at the location of maximum wave elevation, but instead for placements up to 0.6 wavelengths before and up to nearly 0.18 wavelengths after the location of maximum wave elevation. Changing the structure’s position relative to the extreme-wave event changes the maximum horizontal forces by up to ca. 50% (linear focusing) and 22.7% (rogue wave). The variation reduced with increasing structure dimensions, to still ca. 13.8% (linear focusing) and 11.4% (rogue wave) for the fixed vertical cylinder with diameter of 0.2 wavelengths. The results of this study show that, to correctly determine maximum wave-induced loads, investigations must be repeated for different structure placements relative to the extreme-wave event. The work provides recommendations for performing such investigations and outlines related topics for future research.en1878-03422026SpringerExtreme wavemaximum horizontal forcesrogue wavestructure positionwave breakingwave dynamicswave impactwave propagationTechnology::623: Military Engineering and Marine Engineering::623.8: Naval Architecture; ShipbuildingTechnology::620: EngineeringJournal Article10.1007/s42241-026-0017-x