## 3 A Short Overview of Selected Examples of Measuring and Monitoring Systems on Sea Ships
### Ship Performance Monitoring System  
Ship performance monitoring systems [10; 11; 12] are implemented on modern vessels in order to support efficient and environmentally sound operation. Such systems integrate vast amounts of signals and process them with respect to ship energy efficiency. An example of such a system is SeaPerformer developed by Research and Development Company Enamor Ltd. Gdynia, Poland, which cooperates closely with Gdynia Maritime University. SeaPerformer has been developed within the framework of research project co-financed by Polish National Centre for Research and Development (research project POIR.01.01.01-00-0933/15). The system has been successfully implemented on dozens of deep sea ships. SeaPerformer is a modular solution which consists of:  
* Data processing and storage server based on marine industrial computer which serves the purpose of data acquisition, storage and automated processing. Server allows user interaction with the help of dedicated user interface and support ship-to-shore data exchange realized with the help of the existing satellite communication system;
* One or more data collecting units (typically there are two units, one located on the ship bridge for the purpose of navigation signals and one installed in the engine control room for collecting machinery signals);
* Power supply unit featuring system safe shut down in the case of blackout and automatic system start when power is restored;
* One or more high resolution and large size (24\" or more) marine industrial monitors with keyboard and trackball serving user interaction. System interconnection is realized with the help of a dedicated or general ship Ethernet network. This solution simplifies system installation in the case of retrofit projects and allows data access with the use of other computers within the same LAN (Local Area Network). Usually, such a system is capable of the simultaneous recording of a large amount of data. Depending on the type of ship, main engines and subsystems, SeaPerformer collects from a few hundred up to a couple thousand signals. Data collection is performed with the use of two general hardware interfaces: NMEA 0183 for the communication with navigation equipment such as ship GPS, log, echo-sounder, gyro-compass, weather station etc. and Modbus (RTU or TCP) for data collection from machinery e.g., main and auxiliary engines, boilers, fuel system, alarm and monitoring system, loading computer etc. Information collected with the use of the mentioned interfaces are stored in two databases. The high frequency database collects signals with frequency ranging from 1 Hz up to 100 Hz as appropriate, with respect to the nature of the signal. Due to the large amount of information, this database is kept onboard and can be transferred onshore only on request, usually when detailed signal examination is needed for the purpose of troubleshooting. Standard ship-to-shore data exchange is facilitated with used low frequency database created by 1-min averaging of high frequency database. This process, illustrated in Figure 2, allows for significant reduction of data amount and allows for data exchange with the use of a contemporary ship satellite communication system. Data measured directly onboard are supplemented additionally by weather data with the use of ship weather service. Weather data are interpolated along ship track and integrated with data measured onboard. In order to secure communication against unauthorized access, data package is encrypted with use of Rivesta-Shamira-Adlemana (RSA) and Advanced Encryption Standard (AES) algorithms. Data sent from the vessel are stored in cloud server and can be accessed by the owner of the technical office (usually superintendent or fleet manager) for analyses and comparison against the fleet.