“Liquefication” and “Dynamic Separation” Different Aspects of the Same Problem

Abstract

In 2015 the Bulk Jupiter sank during bad weather loaded with bauxite. Nearly automatically everybody considered “liquefaction” to be the prime cause of this accident. Liquefaction is a phenomenon where solid bulk cargo, triggered by the ship movements, starts to behave has a high density viscous liquid in the holds. The stability is negatively influenced by the free surface effect and further research, especially by the Global Bauxite Working Group or GBWG showed that bauxite ore simply will not liquefy even under the worst case shipping conditions. Evidence from real world shipments of bauxites shows that instabilities due to moisture cannot be explained by liquefaction phenomena, but can be under a “dynamic separation” mechanism of instability. Both liquefaction and dynamic separation are caused by an excessive moisture of the bauxite cargo. However, the influence on the stability of the ship is fundamentally different.