# Digital Twin in the Maritime Domain: A Review and Emerging Trends
## 3 Adoption of Digital Twin Technology for the Marine Sector
### Smart Shipping  
With the availability of satellite communication, the onboard modules are easily linked with onshore supporting facilities, rather than opening the standalone data infrastructures onboard holistically to shore operators (Figure 4). As per the Guidance Notes of the American Bureau of Shipping on Smart Function Implementation, they have highlighted the importance of having a DT to support the data infrastructure in onshore processing during Big Data Transfer [34]. It will allow operators to continuously collect, transmit, manage, and analyze the data for real-time monitoring, increase awareness and decision making for both human-initiated decisions and autonomous command and control. It further enhances the ships' situational awareness, navigational safety, and reduction of crew fatigue and human error-related accidents.  
The main requirement of a smart ship can be defined as the ability to perform the intended functions autonomously. The transformation from a traditional human-based system to full autonomy is achieved with the digitalized platforms in the electrified vessels. Smart ships highly depend upon the digitalized marine eco-system, which is focused on autonomous operation.  
Furthermore, Wartsila and Rolls-Royce have announced the successful testing and demonstration of dock-to-dock navigating fully autonomous ferri  
Figure 4: Realtime Satellite Data Link of Smart Ships.  
of the master on-board. Wartsila, with their hybrid-powered ferry _Folgefonn_, made a three-stop route in Norway, while the Rolls-Royce ferry _Falco_ made an unmanned voyage in Finland with autonomous collision avoidance and docking [35].  
This evolution has opened the doorway for DT technology to enter the shipping industry by bringing all experts into a centralized topology, providing powerful analysis, understanding, and diagnostics that are crucial for decision-makers in every stage of the ship's life. This iteration has made the pathway for Ship DT (SDT), which incorporates the basic topology of the DT concept to develop and implement for various applications within the maritime domain. The limits are endless in this effort, but this DT can be primarily based on three main virtues, namely Asset Representation, Operational Behavior Model, and Parameter Measurement/Monitoring. The application of the technology can further be divided into the design phase, manufacturing phase, service phase and retire phase [36]. This encompasses every action that the ship must undergo during her life cycle. It will support the actions from preliminary conceptual design and optimization to the final validation of the model. The developed DT model will then assist the supply and production measures during her building at the shipyard till the final performance trials and commissioning. During the entire service period, DT will be the key tool to performing intended functions during her operational phase. Routine upkeeping of the vessel to Planned Preventive Maintenance (PPM) to Condition-Based Predictive Maintenance (CBPM) will be functioning through the DT model with all historical data accumulated in condition monitoring, prognostics, and diagnostics and even the simulated testing of the systems/components. However, the support it could render during the decommissioning phase has yet to be studied.