Development of an Integrated Monitoring System and Monitoring of Global Hull Loadings on High Speed Mono-Hull

The development of new high speed ships still lacks information on full-scale wave loads and hull beam response in actual operation conditions. Sophisticated measurement technology and monitoring systems are needed in order to measure and monitor hull beam global loadings, encountered sea conditions and ship operation parameters. Integration of all the data during the monitoring and analysis is of extreme importance. VTT developed an innovative monitoring system and applied it to monitor global hull beam loadings of fast mono-hull SuperSeaCat4. The developed integrated monitoring system is described. The monitoring system consists of strain sensors in the SSC4 hull structures to measure hull beam bending and shear response. Hull beam bending moment is detected in several locations by using normal strain gauges, and bending moment distribution along the ship beam is analyzed. Shear strain sensors are installed to measure hull beam shear force and torsion moment. Accelerations are measured at bow, after-body and at the centre of gravity to study inertia effects and accelerations from passenger comfort point of view. In addition, ship motions are measured in 3-dof. Wave radar is used to register the encountered waves. Ship’s operation parameters are monitored by using an autonomous unit with DGPS capability. A modern distributed digital network technology is applied for data collection and integration. The analogue signals are gathered by sub-units which convert a group of analogue signals into digital form. The sub-units are controlled by a master data collection unit via CAN-bus. The master data collection unit processes the data on-line and sends the data to PC which records all necessary information from different sources into a HDD unit. The monitoring campaign was performed in the Gulf of Finland, Baltic Sea. The main characteristics of SuperSeaCat4 and encountered sea conditions are described. Example results of the monitoring campaign are presented. Ship hull beam behavior is illustrated as bending moment distribution, shear forces, accelerations and ship motions. Ship operation parameters are given for the studied cases.