Anti-Rolling Tank helps avoid danger of parametric roll

The phenomenon known as parametric roll means that large container vessels may experience severe roll motions when sailing at low speed in head-on or following seas. MARIN has been involved in testing a system which addresses this problem. MARIN's Seakeeping and Manoeuvring Basin was the scene in September for a series of model tests with a 5500 TEU containership for German company INTERING. The programme was set out to show the effect of their specially designed Anti-Rolling Tank on parametric roll motions.The tests showed a spectacular increase of the wave height level above which the roll motions occur, as can be seen in the adjacent figure.