@article{Efremov_Vasileva_Milanov_2026, author = {Efremov, Dobrin and Vasileva, Aleksandrina and Milanov, Evgeni}, title = {Investigation of Darpa Suboff on the “Suction” Influence to the Maneuvering Forces at High Drift Angles and Shallowly Immersion Conditions}, journal = {TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation}, volume = {20}, number = {3}, pages = {585-591}, year = {2026}, url = {./Article_Investigation_of_Darpa_Suboff_on_Efremov,79,1686.html}, abstract = {The increasing trend of using underwater manned and unmanned vehicles to perform risky missions is visible. The risks are relate to limited spaces or fairways, ensuring sufficient movement speed and safe handling. The conditions that unite these risk factors are maneuverability of underwater apparatus near the free surface. The pressure field around the body affects the nearby free surface and generates waves that subsequently change the pressure distribution over the body. In these modes, the free surface significantly influences the hull hydrodynamic forces and moments. The known suction force in shallow immersion can changes its character radically at angles of attack. It is possible, at high drift angles to become into a force of repulsion from the free surface. The scope of work consists of captive model experiments to analyses the suction phenomenon (Z) influence to the axial resistance (X) and lateral force (Y) for a submarine operating close to the free surface at high-drift-angle. Could be summarize that the forces considered regarding maneuverability in the horizontal plane near the free water surface should not be considered in isolation from those acting in the vertical plane. They are permanently interacting.}, doi = {10.12716/1001.20.03.06}, issn = {2083-6473}, publisher = {Gdynia Maritime University, Faculty of Navigation}, keywords = {Hydrodynamics, Computational Fluid Dynamics (CFD), Manoeuvring, Methods and Algorithms, Underwater Vehicles, Model Tests, Shallow Water Effects, Ship Dynamics} }