The Max-Planck-Institute global ocean/sea ice model, known as the Hamburg Ocean Primitive Equation (HOPE) model, has undergone significant development, particularly in the treatment of horizontal discretization and subgrid-scale processes. The model now uses an orthogonal curvilinear C-grid instead of a staggered E-grid, which improves computational efficiency and reduces numerical diffusion. The model setup features poles over Greenland and the Weddell Sea, providing high resolution in regions associated with the thermohaline circulation. The model includes new formulations for bottom boundary layer (BBL) slope convection, isopycnal diffusion, eddy-induced mixing, and convective adjustment. These improvements enhance the representation of key oceanic processes, such as heat transport and the meridional overturning streamfunction. However, the model still faces challenges, including incorrect Gulf Stream pathways, an overly strong Antarctic Circumpolar Current, and insufficient renewal of Antarctic Intermediate Water. Despite these issues, the model has been successfully coupled to the atmospheric GCM ECHAM5 and run for over 250 years without surface flux corrections. The paper also discusses the implementation of the orthogonal curvilinear grid, the forcing data used, and the results from a 450-year climatologically forced integration.The Max-Planck-Institute global ocean/sea ice model, known as the Hamburg Ocean Primitive Equation (HOPE) model, has undergone significant development, particularly in the treatment of horizontal discretization and subgrid-scale processes. The model now uses an orthogonal curvilinear C-grid instead of a staggered E-grid, which improves computational efficiency and reduces numerical diffusion. The model setup features poles over Greenland and the Weddell Sea, providing high resolution in regions associated with the thermohaline circulation. The model includes new formulations for bottom boundary layer (BBL) slope convection, isopycnal diffusion, eddy-induced mixing, and convective adjustment. These improvements enhance the representation of key oceanic processes, such as heat transport and the meridional overturning streamfunction. However, the model still faces challenges, including incorrect Gulf Stream pathways, an overly strong Antarctic Circumpolar Current, and insufficient renewal of Antarctic Intermediate Water. Despite these issues, the model has been successfully coupled to the atmospheric GCM ECHAM5 and run for over 250 years without surface flux corrections. The paper also discusses the implementation of the orthogonal curvilinear grid, the forcing data used, and the results from a 450-year climatologically forced integration.