Zig-Zag-Test-Manoeuvre for Yaw Stability, IMO Manoeuvring Standards and Crash Stop

This video is now the last of the Yaw Stability series. It shows an introduction on the Zig-Zag-Test-Manoeuvre and describes the procedure how to steer through this periodic rudder manoeuvre, switching the rudder depending on the heading change. Some characteristic parameters are explained, specifically the overshoot angles following counter rudder are suitable to decide on stable and unstable conditions as part of the IMO Standards for ships manoeuvrability.
Samples of stable and unstable ship behaviour demonstrations will be shown by Fast Time Simulation using the SAMMON Planning and the SIMOPT tool. The results are discussed with respect to the IMO limit values. Finally, the effect of yaw stability on the tracks of Crash Stop Manoeuvres are discussed, demonstrating the impact of small turning rates when starting to reverse the engines.