## 4 Advanced Machinery Performance Monitoring  
In recent years, thousands of commercial ships have come to sail across the oceans every day. These commercial ships are operated by companies incorporated in different jurisdictions. Furthermore, these ships are built by hundreds of shipbuilding facilities and have to comply with several international, regional, and national regulations in order to fulfill the safety requirements across a worldwide network of commercial ports. One of the purposes of sailing ships is to carry passengers and goods across oceans. Moreover, the commercial shipping industry and its regulations make international trade possible, safe, and efficient. Figure 11: TENG tilt sensor experimental apparatus [84]. Recently, there has been increasing interest in developing and implementing ship hull structure monitoring systems. However, ship losses are still high. The total ship loss between 2016 and 2019 is presented in Figure 12. During this period, cargo ships faced the highest loss at a total of 120 ships [85]. Furthermore, ships are extremely complex systems. Several essential components on a ship, such as the navigation system, power system, i.e., main engine, and the cargo, make this ship reliable. However, all of the very complex systems of a ship need supervision by monitoring and control systems. As can be seen in Figure 12, a total of 21 ships were lost due to machinery failure between 2016 and 2019. In this section, a review of advanced machinery performance monitoring on ships is presented. Furthermore, these technologies are expected to facilitate the maintenance, safety, and effectiveness of ship operation. Several ship management technologies directed at enhancing the effectiveness and safety of ships have been developed and proposed by many researchers, e.g., [PERSON] et al. [86; 87], who performed research based on the employment of wireless sensor networks for full-scale in-ship application [86]. Their research examined a wireless sensor network (WSN) used to communicate in the ship environment. Two ZPAs (Zigbee Protocol Analyzers) were used as data transmission tests. The results of the wireless communication network are presented in Figure 13. As can be seen, the average delivery ratio was nearly 100% at all proposed distances. Based on the work, the wireless communication network can be used for the abnormal operation of equipment and fire prevention in dangerous regions. [PERSON] et al. [87] also conducted follow-up research in 2009 on the characteristics of wireless sensor networks for full-scale ship application. The ship Hannara, a 3000-ton class training ship, was chosen for this study. The result showed that the characteristics of the wireless sensor network on a test bed ashore also have a successful connection. Figure 12: Total ship loss in 2016–2019. **(a)** Total loss by type of vessel and **(b)** all causes of loss (redrawn based on data in Allianz [85]). Figure 13: Result of the wireless communication tests for the long corridor in the shelter deck. **(a)** Average delivery ratio and **(b)** average radio frequency strength (redrawn based on data in [PERSON] et al. [86]). To this day, as the number of passengers onboard commercial vessels has grown, the concern for ship safety has risen. The safety of passengers on a large ship is the priority. As such, ships have been extensively fitted with several safety systems, i.e., for fire, evacuation, stability, and flooding control. This flooding control, specifically by breach detection, has attracted researchers such as [PERSON] and [PERSON] [88], who presented in the 5 th International Conference on Collision and Grounding of Ships (ICCGS) in Espoo, Finland. This conference is very well known in the field of impact phenomena, i.e., in ship collision and grounding. This study is expected to provide milestone processes to improve the safety of ships. In the work, various combinations of sensor density, noise, and filter length combined with an inverse method were introduced for detecting a breach.