This video shows an introduction on the Spiral-Test-Manoeuvre and describes the procedure how to steer through this manoeuvre and measure the data needed. The results will be displayed in a characteristic diagram allowing to identify stable and unstable conditions and related, detailed information, e.g. spiral loop width and height, rudder angle of neutral effect. Samples of stable and unstable ship behaviour demonstrations will be shown by Fast Time Simulation using the SAMMON Planning tool.
Port Revel is used for shiphandling training of maritime pilots, masters and officers on a 5 ha lake with 11 manned model ships representing 20 vessels, and 4 tugs at scale 1:25 and DGPS tracking system. Instructors are former maritime pilots.
Training on the scale models provides experience that could never be gained on real ships for the simple reason that neither ship-owners nor local authorities would allow such risks to be taken. Scale models allow the shiphandler to make mistakes....
Research on hydrodynamic interaction indicates that if the speed of the ship near a bank is too high, the rudder may be less able to cope with the forces induced and control will be lost. The Nautical Institute highlights this in its latest Mars Report, in which an LPG carrier hit a barge being towed by a tugboat as a result of hydrodynamic forces.