We present the virtual demonstration of a novel ship Anti-Grounding Service in a digital twinned use case scenario in the Port of Hamburg. The scenario is generated from real bathymetry survey data collected in the Port. The virtual model of a Maritime Autonomous Surface Ship travels the route ahead of merchant ships on approach to the Port and is integrated with a real-time high-resolution Multibeam SONAR Simulator that synthesizes underkeel survey data. The automated data processing workflow detects potential grounding hazards in the synthetic survey data and provides a real-time update of the Port nautical chart, which is presented in the Electronic Chart Display and Information System of a Ship Handling Simulator. Our method is the first to consider Multibeam SONAR equipped Maritime Autonomous Surface Ship platforms for provision of ship Anti-Grounding Services. The results validate the full-scale simulation and automated hazard detection workflow and incorporate tests conducted with certified mariners (N=10) to address human factors of introducing new technologies into safety critical situations. The key contributions of this work are summarized as: 1) Validation of Maritime Autonomous Surface Ships as an Anti-Grounding Service delivery platform; 2) Demonstration of a Digital Twin for hydrography survey and bottom hazard detection; and 3) Experimental validation with certified mariners of the antigrounding service Human-Computer Interface on the ship bridge.