Dynamic stability of ships in waves
Our mission is to bridge the gap between academic research and ship operations.
Seaware has been working with different aspects of dynamic stability since the early 90's, with our main focus on operational decision support. Through our collaboration with our
Seaware EnRoute Live customers, we have access to huge amount of ship motion measurements that we continuously learn from. Using this motion measurements database we have been able to investigate several events of real-life large rolling caused by parametric rolling or loss of stability in waves. For example, in 2004 we submitted a report to IMO SLF presenting recordings of parametric roll on a car carrier. Based on the knowledge gained we have developed the new
enhanced dynamic stability module in Seaware EnRoute Live.
What makes a ship sensitive to parametric rolling and loss of stability in waves?
The most important factor driving both these phenomena is the variation of stability in waves. The magnitude of the stability variation is highly dependant on the hull lines. In general, ships with slender lines below the waterline, and more full lines above it, such as large bow flare and wide transom sterns, will exhibit larger variation of stability in waves. Typical ship types that may be sensitive are container ships, car carriers and RoRo's.
Seaware participates actively in a ship dynamics research program together with Wallenius Marine and The Royal Institute of Technology, Stockholm. The primary focus of this program is within the field of dynamic stability research.
Parametric rolling: Simulation of parametric rolling in following irregular sea. Very sudden and violent rolling is typical for this non-linear phenomenon.