Engineering Physics Annotation << Back Physical Processes of Behavior on Waves of a Moored Vessel in the Prigorodnoye Port, Sakhalin Island Kovalev D.P., Kovalev P.D., Borisov A.S., Zarochintsev V.S The paper considers the results of studies of the features of physical processes during the pitching of moored vessels, as a dynamic system, for the Prigorodnoye port of the Sakhalin region, which is the main port for the transport of liquefi ed gas and oil from fi elds on Sakhalin Island. The calculated spectra of sea level fl uctuations using the time series recorded at the Prigorodnoye port made it possible to determine the periods of wave processes for a range of periods from 2 seconds to 30 minutes, at which manifestation of the harbor oscillations phenomenon is possible. The calculation of the pitching periods for a gas carrier and oil tanker – typical vessels mooring in the port of Prigorodnoye to the Jetty - a special berth for receiving gas carriers, and an outrigger oil loading berth. The obtained results of observations of the waves made it possible to simulate the movement of ships for non-impact mode and impact mode at the dampers of the berth. The behavior of a dynamic system is considered – the movement of ships under the infl uence of an external force – incoming waves, with using a second-order differential equation with an external exciting force. The infl uence of the coeffi cient of viscous damping and the rigidity of the mooring lines on the reaction of the dynamic system without impact on the berth and for the impact oscillator mode is shown. The dynamic system is modeled using the Duffi ng equation for situations where ships are affected by infragravity waves with periods of 64.6 s and 94.1 s for determine of possibility the of the transition of the movements of the dynamic system to chaotic oscillations. Keywords: ship pitching, sea waves, dynamic system, phase portrait, impact oscillator DOI: 10.25791/infi zik.11.2023.1363 Pp. 03-17.